Table of Content

20 April 2020, Volume 31 Issue 4

Previous Issue    Next Issue

Seedling regeneration and spatial correlation between seedlings and seed trees in Castanopsis hystrix plantation by large diameter wood cultivation in south subtropical China

XU Hao-cheng, ZHENG Lu, WANG Hong-xiang, NONG You, CHEN Yong-kang, LI Meng, CAI Dao-xiong, YOU Ye-ming

2020, 31(4):  1055-1062.  doi:10.13287/j.1001-9332.202004.009

Asbtract ( 294 )   PDF (1933KB) ( 81 )  

Using the paired correlation equation g(r) in the spatial point patterns, we investigated the regeneration characteristics and spatial patterns of Castanopsis hystrix seedlings and the spatial correlation with the seed trees in the plantation by large diameter wood cultivation in south subtropical China. The results showed that natural seedling regeneration in C. hystrix plantation was good, which were widely distributed in the whole plantation. The seedling regeneration were mainly contributed by root sprouts, accounting for 73.6% of the total. The number distribution of C. hystrix seedlings in different age classes showed a pyramidal shape, with the contribution of diameter classⅠ, Ⅱ and Ⅲ being 64.3%, 29.3% and 6.4% of the total, respectively. The C. hystrix seedlings mainly presented aggregated distribution in small scale (<15 m). With the increases of size classes and spatial scales, the aggregation strength gradually weakened and finally presented random distribution. The spatial correlation between seedlings and seed trees was not significant with the increases of size classes or spatial scale.

Age- and organ-related variances in fire resistance traits of typical tree species in subtropical China

ZENG Su-ping, LIU Fa-lin, ZHAO Mei-fang, AI Yao, CHEN Xiao-wei

2020, 31(4):  1063-1072.  doi:10.13287/j.1001-9332.202004.008

Asbtract ( 274 )   PDF (1224KB) ( 47 )  

We investigated the fire resistance conferred by different forest age groups (young, middle-age and mature forest) and organs (leaf, branch, and bark) of six typical tree species (Myrica rubra, Schima superba, Symplocos sumuntia, Machilus pingii, Castanopsis eyrei, and Quercus glauca) in Qingshigang national forest farm, Yanling County, Hunan Province, subtropical China. We measured morphological, physical, and chemical properties that could be used as proxies for fire resistance and examined the variances of fire resistance among different organs and age groups in the same tree species. Further, we comprehensively ranked all the tree species by their capacity in fire resistance. We found considerable variation in fire resistance among organs and age groups. Compared with branches and barks, leaves had relatively higher water content (53.7%), higher crude ash content (4.5%), and lower crude fiber content (23.9%). Fire resistance of trees decreased first and then increased with increasing stand age. Trees in middle-aged stage showed the lowest contents of water, crude ash, and crude fiber. The comprehensive scores of fire resistance for diffe-rent organs were significantly different among species. Fire resistance of leaves generally decreased in the order of M. pingii > C. eyrei > S. sumuntia > M. rubra > S. superba > Q. glauca. For branches, M. pingii and C. eyrei showed the strongest fire resistance, followed by M. rubra and S. superba. For barks, S. superba and C. eyrei were relatively stronger in fire resistance than other species, while M. pingii and Q. glauca were the weakest. The comprehensive scores of fire resistance performance of species were different. S. superba (1.033) and M. rubra (0.526) were the most fire-resistant species, while M. pingii (-0.405) and Q. glauca (-1.151) were the least fire-resistant. Therefore, S. superba and M. rubra were the preferred tree species for fire prevention forest belt in forests of subtropical southern China.

Effects of different regeneration patterns on soil dissolved organic matter degradation in Castanopsis carlesii forests of subtropical China

SUN Ying, GAO Ying, CHEN Hui, SI You-tao, BAO Yong, JIAO Hong-zhe

2020, 31(4):  1073-1082.  doi:10.13287/j.1001-9332.202004.033

Asbtract ( 282 )   PDF (1166KB) ( 74 )  

Biodegradability of dissolved organic matter (DOM) affects stabilization and mineralization of soil organic matter, which is of great significance to soil nutrient cycling. In order to explore the effects of forest regeneration on soil DOM degradation, soil DOM solution was sampled in a natural Castanopsis carlesii forest (NF), a secondary forest of C. carlesii (SF), and an artificial-assisted regeneration forest of C. carlesii (AR) in a sub-tropical area and conducted 42-day laboratory incubation. The results showed that: 1) both the degradation rate of soil dissolved organic carbon (DOC) and the ratio of labile DOC were as follows: SF>AR>NF; dissolved organic nitrogen (DON) and microbial biomass carbon (MBC) are the factors significantly affecting the ratio of labile DOC; 2) stable DOC accounted for the majority of soil DOC in all the three forest types (72.3%-94.6%), which had long turnover time and contributed to the formation of stable soil organic matter (SOC); 3) the initial humification index in emission mode (HIX_em) of soil DOM would affect the turnover time of labile DOC. The spectral structure of DOM changed dynamically during the degradation process, indicating that microorganism would turn to degrade aromatic and hydrophobic fractions for carbon source after the depletion of labile DOM. Overall, the transformation from NF of C. carlesii into SF and AR could increase the proportion of the easily degradable DOC, and enhance the biodegradability of soil DOM, which were not conducive to the accumulation of SOC.

Response of foliar δ¹³C in Populus euphratica and Tamarix sp. to different groundwater depths in the oasis of desert hinterland

MARHABA·Nijat, DAI Yue, SHI Qing-dong, LI Tao, XIAO HELAITI·Bayi, ANWAIER·Abudureyimu

2020, 31(4):  1083-1087.  doi:10.13287/j.1001-9332.202004.004

Asbtract ( 255 )   PDF (711KB) ( 42 )  

Water use efficiency of plants in arid regions plays a key role in affecting the distribution and water use of plants. We analyzed the responses of water use efficiency of Populus euphratica and Tamarix sp. to different groundwater depths by measuring foliar δ¹³C of the two dominant species in a desert hinterland. The results showed that as the groundwater depth increased from 2.1 m to 4.3 m, foliar δ¹³C of Tamarix sp. increased slightly and remained relatively stable. Tamarix sp. had a more stable water use efficiency to adapt to the arid environment. Foliar δ¹³C of P. euphratica first slightly decreased and then increased. P. euphratica improved its water use efficiency to adapt to drought stress. At the same groundwater depth, foliar δ¹³C of Tamarix sp. was higher than that of P. euphratica, indicating that water use efficiency of Tamarix sp. was higher than that of P. euphratica.

Effects of broadleaved tree plantation on soil phosphorus fractions and availability in diffe-rent soil layers in a logged Cunninghamia lanceolata woodland

WANG Tao, WAN Xiao-hua, WANG Lei, ZOU Bing-zhang, WANG Si-rong, HUANG Zhi-qun

2020, 31(4):  1088-1096.  doi:10.13287/j.1001-9332.202004.006

Asbtract ( 322 )   PDF (1352KB) ( 326 )  

Phosphorus (P) limitation is one of the major issues for the management of subtropical plantations. Understanding the effects of tree species transition from conifer to broadleaved trees on soil P fraction and availability in different soil layers are of great significance for the sustainable development of subtropical forests. We compared changes in soil chemical properties, P fraction and availability across 0-100 cm soil profile between Mytilaria laosensis and Cunninghamia lanceolata plantations, which were initially reforested from C. lanceolata plantation in the spring of 1993. The results showed that soil organic P content in both plantations decreased significantly with soil depth. Compared with C. lanceolata, the M. laosensis plantation significantly increased soil available P content by 35.7% and 86.2% in the 0-10 and 10-20 cm, respectively. The contents of soil labile P and moderately labile P decreased significantly with soil depth in both plantations. The contents of labile P and moderately labile P were significantly higher in the surface soil (0-20 cm), while the non-labile P in the 80-100 cm was increased by 13.6%, and the free iron content in the 20-80 cm significantly decreased. Results of redundancy analysis showed that dissolved organic carbon and free iron were the most important factors influencing P fraction in those plantations. Tree species transition from C. lanceolata to M. laosensis could change the pattern of soil P fraction in soil profile, and greatly enhance soil P availability.

Composition and fractal features of soil micro-aggregates in microsites of different types of treefall gaps

LAN Hang-yu, DUAN Wen-biao, CHEN Li-xin, QU Mei-xue, WANG Ya-fei, YANG Xi-feng, MENG Si-jing, CHEN Jia

2020, 31(4):  1097-1105.  doi:10.13287/j.1001-9332.202004.028

Asbtract ( 377 )   PDF (699KB) ( 215 )  

Through field survey and laboratory analysis, we examined the composition and fractal features of soil micro-aggregates in different types of treefall gaps and microsites (pit bottom and mound top) in broad-leaved Korean pine forest and spruce-fir-Korean pine forest. Results showed that the contents of soil microaggregates under the classes of 0.25-2 mm and 0.05-0.25 mm were higher in both forest types, ranging from 25.7% to 50.7% and from 27.0% to 42.8%, respectively, and that of <0.002 mm was the lowest, ranging from 4.4% to 8.9%. In the pit bottom and mound top of gaps, soil bulk density was higher in both forest types. Soil nutrient content in mound top was higher than that in pit bottom and was higher in broad-leaved Korean pine forest than spruce-fir-Korean pine forest. Soil microaggregates of <0.002 mm had no correlation with soil physical and chemical properties, whereas that of 0.25-2 mm and 0.002-0.02 mm had significantly positive and negative correlation with soil non-capillary porosity, total porosity, aeration porosity, organic matter, total phosphorus, total nitrogen and organic carbon, respectively. On the whole, soil fractal dimension (D) and the proportion of characteristic soil micro-aggregates (PCM) in broad-leaved Korean pine forest were larger than those in spruce-fir-Korean pine forest, and the ratio of soil microaggregates diameter (RMD) in mound top and pit bottom was increased in two forest types. Soil D and PCM had no significant correlation with soil physical and chemical properties, while RMD was negatively correlated with capillary porosity, total porosity, soil bulk density and aeration porosity. In two forest types, the formation of mound and pit microsites could decrease the larger size micro-aggregates and the stability of soil micro-aggregate, increase soil D and PCM, and signifi-cantly increase RMD. RMD could be used as a quantitative index of soil physical and chemical properties in pit and mound microsites of forest.

Breeding-system comparison between alien invasive Solanum rostratum and its non-invasive congener S. americanum

DING Pin-yi, MAO Kai-qi, LI Heng-yu, LU Yi-wei, WANG Li-xin, HAO Jian-hua

2020, 31(4):  1106-1112.  doi:10.13287/j.1001-9332.202004.003

Asbtract ( 537 )   PDF (664KB) ( 70 )  

Solanum rostratum is a severely invasive alien plant species in China. Using four S. rostratum populations and non-invasive congener S. americanum, we conducted a common garden experiment to compare their breeding systems. No significant difference in average seed set between the two species under open pollination and supplementary pollination conditions. However, under the bagged self-pollination condition, S. rostratum had significantly lower average seed set (29.5%) than S. americanum (47.0%). No fertile seeds were detected in the emasculation treatments for both species, suggesting no autonomous apomixis in them. S. rostratum had a lower average autofertility index (0.38) than S. americanum (0.64). S. rostratum had higher average pollen limitation index (0.29) and average pollinator’s contribution index (0.49) than S. americanum (0.08 and 0.31, respectively). S. rostratum was found in 12 provinces of China and in 3835 locations globally, which were lower than S. americanum with 18 Chinese provinces and 10897 locations globally. The invasive alien S. rostratum had lower self-compatibility than the non-invasive alien S. americanum. Thus, the invasiveness of those two species was not significantly correlated with their self-compatibility, but positively correlated with their distribution range.

Prediction models of sapwood density, heartwood density, and bark density in Larix olgensis plantation

PENG Yu-xin, LI Feng-ri, LIU Fu, DONG Li-hu

2020, 31(4):  1113-1120.  doi:10.13287/j.1001-9332.202004.007

Asbtract ( 392 )   PDF (614KB) ( 263 )  

In this study, the Beta regression models of sapwood, heartwood, and bark density of Larix olgensis were constructed. A total of 35 trees were destructively sampled from plantations in three different sites, Linkou Forestry Bureau of Heilongjiang Province, Dongjingcheng Forestry Bureau, and Maoershan Experimental Forest Farm of Northeast Forestry University. AIC, R², BIAS, RMSE and LRT were used as the goodness-of-fit statistics to compare and select the most optimal models for sapwood, heartwood, and bark density. The jackknife resampling technique was used to verify and evaluate the developed models. The results showed that the independent variables of the optimal sapwood, heartwood, and bark density model were not identical. Sapwood density had a good relationship with tree age, tree height, relative height, and the square of relative height. The independent variables of the optimal heartwood density model were annual growth, relative height, and the square of relative height. The independent variables of the optimal bark density model were tree age, annual growth, relative height, and the square of relative height. The analysis of the optimal model showed that from the base to the tip of the trunk, sapwood density decreased gradually, heartwood density initially decreased and then increased regularly, bark density initially increased and then decreased gradually. The established Beta regression models could predict sapwood, heartwood, and bark density of L. olgensis at any position in the research area and be an essential basis for the study of trunk average density and biomass.

Effects of hydrogen sulfide on mitochondrial function in sweet cherry stigma and ovary under low temperature stress

WEI Guo-qin, TAO Ji-han, FU Quan-juan, HOU Sen, YANG Xing-hua, SUI Shu-guang, YU Xian-mei, SUN Yu-gang

2020, 31(4):  1121-1129.  doi:10.13287/j.1001-9332.202004.030

Asbtract ( 323 )   PDF (1891KB) ( 203 )  

To investigate the effects of H₂S on mitochondrial functions under low temperature stress, we analyzed the effects of 0.05 mmol·L^-1 NaHS and 15 μmmol·L^-1 HT (hypotaurine and H₂S scavenger) on mitochondria antioxidant enzyme activities and mitochondrial permeability transition pore, mitochondrial membrane fluidity, mitochondrial membrane potential, Cyt c/a ratio and H⁺-ATPase activity in sweet cherry stigma and ovary with sweet cherry variety Zaodaguo under -2 ℃ low temperature stress. The results showed that low temperature stress increased the concentrations of mitochondrial H₂O₂ and MDA, enhanced the mitochondrial membrane permeability, but decreased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H⁺-ATPase acti-vity. Application of NaHS at 0.05 mmol·L^-1 could effectively reduce the concentrations of H₂O₂ and MDA, and keep higher activities of SOD, POD and CAT of mitochondrial for longer time. Furthermore, application of 0.05 mmol·L^-1 NaHS could decrease mitochondrial membrane permeability while increase mitochondrial membrane fluidity, membrane potential, Cyt c/a and H⁺-ATPase activity in stigma and ovary under low temperature stress. The effects of NaHS were completely offset by HT addition. The results suggested that exogenous H₂S could alleviate the oxidative damage on stigma and ovary stress through decreasing H₂O₂ accumulation, regulating mitochondria antioxidant system, increasing H⁺-ATPase activity, and mitigating mitochondria function under low temperature.

Effects of three intercropping species on growth, nutrition absorption, and fruit quality of oriental melon

MA Ying-jie, DENG Hai-feng, XU Chuan-qiang

2020, 31(4):  1130-1138.  doi:10.13287/j.1001-9332.202004.021

Asbtract ( 323 )   PDF (660KB) ( 158 )  

To explore the effects of different intercropping species on growth, nutrition absorption, and fruit quality of oriental melon, we examined plant height, stem diameter, root activity, contents of mineral elements (N, P, K, Ca and Mg), and fruit quality and yield of oriental melon under the oriental melon monoculture (MM), intercropping of fennel/oriental melon (FM), tillered-onion/oriental melon (TM), or wormwood/oriental melon (WM). Results showed that plant height of intercropping treatments was significantly higher than that of the monoculture over time. The stem diameter of the FM and TM treatments was significantly higher than that of the MM treatment, while there was no significant difference between the WM and MM treatments. At the stretch tendril stage, fruit setting stage, and fruit expanding stage, root activity of FM treatment was significantly higher than that of MM and TM treatments. The mine-ral elements contents of oriental melon plants in three intercropping treatments were higher than that in MM treatment in different degrees, with the mine-ral elements contents of FM treatment being higher than that of TM and WM treatments. The single fruit weights of FM and TM treatments did not differ from the MM treatment. The fruit quality indices of FM treatment were not lower than MM treatment, while some fruit quality indices (including the contents of glucose, fructose, and sucrose) of WM and TM treatments were lower than that under MM treatment. In summary, fennel was a suitable species for intercropping with the oriental melon.

Effects of nitrogen application rate on the growth traits in seedlings of different quinoa cultivars

ZHAI Feng-qiang, CAI Zhi-quan, LU Jian-mei

2020, 31(4):  1139-1145.  doi:10.13287/j.1001-9332.202004.010

Asbtract ( 480 )   PDF (2744KB) ( 320 )  

Effects of five different nitrogen application rates (i.e., N₀, 0 g·kg^-1; N₁, 0.05 g·kg^-1; N₂, 0.1 g·kg^-1; N₃, 0.15 g·kg^-1; N₄, 0.2 g·kg^-1) on the growth of seedlings of eight different quinoa cultivars were investigated in a pot experiment. The results showed that: 1) Across different nitrogen application rates, cultivar GB22 and OY had the highest biomass, but cultivar B2 had the lowest value. The highest flower mass ratio, stem mass ratio, root mass ratio, and leaf mass ratio were found in cultivar B2, GB22, R1, and W23, respectively. 2) The rate of nitrogen application significantly affected seedling growth. Compared with the control (N₀), the maximum net photosynthetic rate and biomass accumulation were significantly higher in the lower nitrogen applications (i.e., N₁ and N₂ treatments), but were lower in the higher nitrogen applications (i.e., N₃ and N₄ treatments). The significant interactions between cultivar and nitrogen application rate on plant biomass indicated that different quinoa cultivars responded differently to nitrogen rate. The optimum nitrogen application rate (Nopt) required for cultivar R1, MY11, GB22 and OY was 0.05 g·kg^-1; while that of cultivar GB11, DB, and B2 was 0.1 g·kg^-1; but for cultivar W23, Nopt was less than 0.05 g·kg^-1. 3) The interactions between cultivar and nitrogen application rate significantly affected biomass allocation. Below the highest nitrogen rate used (i.e., less than 0.2 g·kg^-1), the flower and leaf biomass allocation increased with the increasing nitrogen rates. 4) Across different cultivars and nitrogen application rates, plant biomass was positively correlated to the maximum net photosynthetic rate, plant height, ground diameter, and specific leaf area, respectively. These results provided valuable information for the nutrition management of different quinoa cultivars.

Effects of annual whole-film mulching on freezing-thawing characteristics, moisture, and temperature distribution of maize soil in semi-arid area

WANG Hong-li, ZHANG Xu-cheng, YU Xian-feng, HOU Hui-zhi, FANG Yan-jie, MA Yi-fan

2020, 31(4):  1146-1154.  doi:10.13287/j.1001-9332.202004.027

Asbtract ( 306 )   PDF (2278KB) ( 178 )  

Based on a 3-year field experiment (2015-2017) with two treatments, annual whole-film mulching (PM) and uncovered (CK), we analyzed the relationship between soil temperature, moisture, and soil hydrothermal movement in semi-arid area. The results showed that freezing-thawing processes under both PM and CK were one-way freezing and two-way melting. Compared with CK, the freezing period in PM treatment was lagged, freezing rate was slowed down, freezing depth was 20 cm shallower, but melting rate was faster, and melting period was shortened by 6-7 days. In freezing period, soil temperature gradients of PM and CK were positive, with heat being transmitted toward top soil layer, and the conduction strength in PM treatment was greater than CK. During the melting period, soil temperature gradient of PM was also positive, with heat being transmitted toward upper soil layer, and that of CK was conversed. Soil water in PM treatment transported to upper soil layer during freezing-thawing period, but it appeared a “down-up-down” movement mode under CK in freezing period, “up-down” in thawing period. There was positively correlation between temperature and moisture gradient in the freezing period under both PM and CK treatments, with closer correlation in PM than CK. During melting period, soil temperature and moisture gradient was positively correlated in PM treatment with soil heat and moisture moved upward synchronously, while that in CK was negatively correlated with soil heat and moisture simultaneously moved to the lower layer soil. Driven by soil temperature and moisture gradient, soil temperature in 0-10 cm, 10-20 cm and 20-30 cm layers increased by 1.13-1.34 ℃, 0.96-1.24 ℃ and 0.89-1.32 ℃, while average soil water content increased by 3.4%-5.6%, 1.4%-2.2% and 6.7%-7.8%, respectively in PM treatment before sowing. Our results indicated that PM could provide water and heat protection for re-greening of winter crop and sowing, emergence and seedling of spring-sown crops in semi-arid areas.

Characteristics of soil fertility during soil fertilization from parent material of a Mollisol in Northeast China

LI Na, HAN Xiao-zeng, SHENG Ming, LONG Jing-hong

2020, 31(4):  1155-1162.  doi:10.13287/j.1001-9332.202004.026

Asbtract ( 380 )   PDF (1498KB) ( 319 )  

Based on a long-term field experiment located in the central region of Mollisol in Northeast China, we examined the changes of soil fertility and nutrient supply capacity of the newly-formed soils with pot experiment after 14-year different agricultural management practices from parent material (PM) (down to 2.0-3.0 m depth) of a Mollisol, and finally tried to optimize pre-ferential agricultural practices improving soil fertility of seriously eroded PM. After 14-year different agricultural practices, soil organic carbon, total nitrogen, stability of soil aggregate and other rela-ted soil nutrient contents improved compared with PM. Soil fertility level of the newly-developed soils significantly affected nutrient supply capacity for wheat in the pot experiment. Results from principal component analysis showed that soil fertility developed toward to the surface Mollisol after 14 years of different agricultural practices from PM. Surface soils with higher organic carbon inputs in arable soil with chemical fertilizer plus all aboveground biomass incorporated and those in no-tilled alfalfa soil were much approached to surface Mollisol, followed by arable soil with fixed amount of organic inputs and natural fallow soil, while soils without and with only chemical fertilizer were much closed to PM. Our results indicated that 14-year organic carbon inputs improved soil aggregate structure and the decomposition of organic carbon entering into soil, changed soil physical and biochemical properties, and hence caused maturing of soil fertility of PM. Straw returning, organic manure application, and planting alfalfa were recommended for improving soil fertility of eroded soil. These findings would give a better scientific basis for high-efficient fertilization and management practices in eroded Mollisol region.

Soil fertility characteristics and their influencing factors in tea plantations of Jiangxi Pro-vince, China

LIN Xiao-bing, SUN Yong-ming, JIANG Xin-feng, HUANG Shang-shu, HE Shao-lang, YU Pao-lan, WANG Yong-gang

2020, 31(4):  1163-1174.  doi:10.13287/j.1001-9332.202004.022

Asbtract ( 648 )   PDF (1601KB) ( 134 )  

To investigate soil fertility status and characteristics of typical tea plantations, we selec-ted 372 typical tea plantations of 21 areas across Jiangxi Province and analyzed the soil nutrient, spatial data, and their correlations with topography, soil type, elevation and plantation age. The results showed that soil pH, organic matter, alkaline nitrogen, available phosphorus, available potassium, total nitrogen, total phosphorus and total potassium of tea plantation in Jiangxi reached 53.9%, 60.1%, 56.1%, 22.9%, 38.5%, 43.7%, 11.1% and 95.5% of indices of high fertility, high efficiency and high yield tea plantation, respectively, with the available phosphorus showing a strong variation. Soil available copper, zinc, iron, manganese and boron reached 76.3%, 74.2%, 96.8%, 73.1% and 0.0% of the first-class standards for soil trace elements, respectively. Tea plantations with highest soil fertility located in central Jiangxi, followed by northeastern and northwestern Jiangxi, and lowest in southern Jiangxi. Soil pH was significantly positively correlated with organic matter, alkaline nitrogen, available phosphorus, available potassium, total nitrogen and total phosphorus but not for total potassium. For different topography, soil fertility was highest in the flat land, followed by the high mountains, and lowest in the mountains and hills. Across different soil types, soil fertility was higher in paddy soil, sandy soil and mountain yellow brown soil, followed by yellow soil, red-yellow soil and purple soil, and lowest in red soil. Soil pH, organic matter and total potassium increased while available phosphorus decreased with altitude. The organic matter, alkaline nitrogen, available phosphorus, total nitrogen and total phosphorus increased, but soil pH decreased with time. In summary, soil fertility of tea plantations in Jiangxi Province was generally good, with high organic matter, total potassium, available copper, zinc, iron and manganese. However, soil was acidic, available phosphorus and total phosphorus content was low, available boron was seriously limited. We suggest increase soil pH and potassium supply in central Jiangxi, increase potassium and nitrogen fertilizer supply in northeastern Jiangxi, increase organic matter and phosphorus fertilizer supply in northwestern Jiangxi, and increase nitrogen, phosphorus and potassium supply combined with organic fertilizers in southern Jiangxi. High mountain tea plantations should enhance available phosphorus and potassium supply. Mountain tea plantations should enhance nitrogen and phosphate supply. Tea plantations with red and yellow soil should increase pH and total potassium supply. Tea plantations with red soil should apply nitrogen, phosphorus and potassium fertilizers combined with organic fertilizers. Tea plantations with yellow soil and mountain yellow brown soil required additional phosphorus supply, and tea plantations with purple soil should increase soil organic matter supply. Tea plantations need to increase dolomite powder, physiological alkaline fertilizers and organic fertilizers to prevent soil acidification.

Evaluation of comprehensive potential productivity and resource utilization efficiency of Camellia oleifera in Jiangxi Province, China

WANG Xiao-jun, LIU Guang-xu, XIANG Ai-cun, XIAO Tong

2020, 31(4):  1175-1184.  doi:10.13287/j.1001-9332.202004.029

Asbtract ( 414 )   PDF (1234KB) ( 245 )  

As an area suitable for the plantation of Camellia oleifera, Jiangxi had a low degree of development and utilization. Evaluating its potential productivity and resource utilization efficiency could provide reference for optimizing C. oleifera planting division, increasing yield and rationally utilizing land resources. Natural production potential of C. oleifera in Jiangxi was estimated by stepwise revised potential attenuation method. The comprehensive potential productivity was estimated by combined with social efficiency coefficient, with the resource utilization efficiency being evaluated. There were three main results. 1) Potential productivity of C. oleifera in Jiangxi varied from 10229 to 17724 kg·km^-2, which decreased from the south to the northwest, with an average potential of 12550 kg·km^-2. After classification, the area with higher and highest potential productivity reached 51656 km², accounting for 31.1% of the total area. Among the cities, Ganzhou had the highest potential productivity. 2) The changes of potential productivity of C. oleifera ranged from 2223 to 3857 kg·km^-2, with small regional difference for various levels. The resource satisfaction rate ranged from 69.3% to 122.7%, with small regional difference. The resource utilization efficiency varied from 49.1% to 85%. Regional utilization rate at all levels differed obviously. 3) The estimated comprehensive potential productivity was in line with the real production of C. oleifera in Jiangxi, and the assessed resource utilization efficiency was consistent with natural and social conditions. These results could be used as a reference for related research and policy making.

Biochar addition improves soil phosphorus availability: A meta-analysis

ZHAN Ya-nan, WANG Zhi, MENG Ya-li

2020, 31(4):  1185-1193.  doi:10.13287/j.1001-9332.202004.024

Asbtract ( 596 )   PDF (1869KB) ( 292 )  

Biochar is a potential source for improving soil fertility and crop yield by enhancing phosphorus (P) availability. But the information on quantitative effect of biochar addition on soil P availability is still limited. To address this query, we conducted a meta-analysis with 507 data from 95 eligible literature. The results showed that irrespective of biochar characters (raw material, C:N ratio, pyrolysis temperature, application rate), soil characteristics (texture, pH, organic carbon content), and fertilizer application, biochar addition significantly improved soil available P content by 57.6%. Meanwhile, biochar addition promoted P utilization of crops. The response ratios of plant P concentration to biochar addition were generally lower than those of soil available P. The average response ratio of plant P concentration was 30.6%. The biochars, derived from livestock manure, low-temperature pyrolysis, with lower C:N ratio, alkaline, or higher application rate, were more effective to improve soil available P content and plant P concentration in sandy and loamy soils. For main enzymes involved in P cycle, biochar addition increased activity of alkaline phosphatase (2.8%) but decreased the acid phosphatase activity (17.8%). Overall, biochar addition positively affects soil available and plant P concentration, but has a minute effect on soil phosphatase. The improvement of soil P availability might mainly be ascribed to a great amount of active P fractions in biochar itself.

Fractional vegetation cover and topographic effects in Pisha sandstone area of Northwest China in 2000-2018

WANG Rui-jie, YAN Feng

2020, 31(4):  1194-1202.  doi:10.13287/j.1001-9332.202004.005

Asbtract ( 373 )   PDF (2077KB) ( 322 )  

Based on MODIS-EVI data and binary pixel model, we calculated fractional vegetation coverage (FVC) in Pisha sandstone area of Northwest China from 2000 to 2018. The topographic effects on fractional vegetation coverage was analyzed from elevation, slope, and aspect using digital elevation model (DEM) data. From 2000 to 2018, FVC in Pisha sandstone area of Northwest was relatively low, which increased with a rate of 2.43·a^-1. The positive anomaly of FVC existed in 12 years, with higher positive anomaly FVC mainly in 2018 and 2013. The negative anomaly of FVC existed in seven years, with the lower negative anomaly of FVC mainly in 2000 and 2001. The spatial distribution of FVC in Pisha sandstone area decreased from southeast to northwest, which differed significantly among different types, with that in bare Pisha sandstone being the lowest, followed by sand-covered Pisha sandstone, and soil-covered Pisha sandstone area being the highest. The FVC in this area had an average increasing rate of 0.0031, suggesting an improved vegetation growth status. Analysis of elevation-aspect effect showed that aspect had a great influence on FVC at the elevation no more than 1000 m and more than 1500 m in bare Pisha sandstone and sand-covered Pisha sandstone areas, respectively. The aspect of soil-covered Pisha sandstone had a small influence on FVC, its influence was relatively large at 1200-1300 m. When the slope of Pisha sandstone area was no more than 15°, the slope-aspect effect of FVC was not obvious. When the slope was more than 25°, FVC of shady and semi-shady slope in bare and sand-covered Pisha sandstone areas was larger than that of sunny and semi-sunny slopes. For soil-covered Pisha sandstone, when the slope was more than 15°, FVC of semi-shady and semi-sunny slopes was larger than that of shady and sunny slopes.

Changes of growing season NDVI at different elevations, slopes, slope aspects and its relationship with meteorological factors in the southern slope of the Qilian Mountains, China from 1998 to 2017

FU Jian-xin, CAO Guang-chao, GUO Wen-jiong

2020, 31(4):  1203-1212.  doi:10.13287/j.1001-9332.202004.018

Asbtract ( 741 )   PDF (4841KB) ( 501 )  

Qilian Mountains is an important water conservation area in Northwest China, which is the boundary between the first and second steps of China’s topography and is sensitive to climate change. Based on the data of temperature, precipitation, normal difference vegetation index (NDVI), and digital elevation model (DEM) data, we analyzed NDVI change and its relationship with temperature and precipitation along the elevation, slope and slope aspect in the southern slope of Qilian Mountains using tendency analysis method, wavelet analysis and correlation analysis. The results showed that, from 1998 to 2017, NDVI value of the growing season presented increasing trend by a rate of 0.023·10 a^-1. Changes of NDVI differed at different elevations, slopes and slope aspects. NDVI increased first and then decreased with elevation. The vegetation coverage at 2700-3700 m was good, and degraded in the area of >4700 m. NDVI reduced with the increases of slope, which showed little difference in different slope aspects but was better in sunny slope than in shade slope. NDVI of the growing season was closely related with temperature and precipitation. NDVI, temperature and precipitation in growing season all had a 14-year cycle. Vegetation at different elevations, slopes and slope aspects was differently affected by temperature and precipitation. Vegetation in areas with altitude <3700 m, >4700 m, slope <25° and each slope direction was more sensitive to precipitation.

Variation characteristics of NDVI and its response to climatic change in the growing season of Changbai Mountain Nature Reserve during 2001 and 2018

ZHANG Yuan, YUAN Feng-hui, WANG An-zhi, GUAN De-xin, DAI Guan-hua, WU Jia-bing

2020, 31(4):  1213-1222.  doi:10.13287/j.1001-9332.202004.020

Asbtract ( 531 )   PDF (3095KB) ( 430 )  

To understand the dynamics of temperate forest in Northeast Asia and its response to climate change under the scenario of global change, we examined the temporal and spatial changes of normalized difference vegetation index (NDVI) and their correlation with temperature and precipitation of Changbai Mountain Nature Reserve in the growing season during 2001 and 2018, based on the remote sensing database of MODIS with a resolution of 250 m, land surface temperature data with a resolution of 1 km and meteorological data in the studied and surrounding area. The results showed that, in the growing season of 2001-2018, the averaged NDVI value of the study area was 0.711. Vegetation coverage was relatively high, increasing with a rate of 0.0025·a^-1. The temperature showed an extremely significantly increasing trend (0.032 ℃·a^-1), the rate of which was higher than that at global level. Precipitation also showed a significantly increasing trend (5.54 mm·a^-1) with increased interannual variation. Spatially, NDVI generally was higher in the northwest and decreased with elevation. During the study period, the area with increased NDVI accounted for 46.2%, mainly concentrated in the north and south central high-altitude areas, while 53.8% of total area remained unchanged or slightly decrease. NDVI of the study area was mainly affected by temperature. At the annual scale, NDVI and land surface temperature were positively correlated, with 90.2% presented positive correlation and 43.6% significantly correlated. At the monthly scale, the impact of temperature on NDVI was more significant at the beginning and the end of growing season.

Time-series characteristics of drought and flood in spring soybean growing season and its effect on soybean yield in Heilongjiang Province, China

LI Xiu-fen, GUO Zhao-bin, ZHU Hai-xia, WANG Ping, GONG Li-juan, JIANG Li-xia, ZHAO Hui-ying

2020, 31(4):  1223-1232.  doi:10.13287/j.1001-9332.202004.016

Asbtract ( 420 )   PDF (1997KB) ( 164 )  

Under the background of climate change, the spatial-temporal distribution of precipita-tion in Heilongjiang Province is uneven, and drought and flood frequently change, which is not conducive to the safety of soybean production for the province. To clarify the influence mechanism of drought and flood in the growing season on soybean yield in Heilongjiang Province, we analyzed the time-series characteristics of drought and flood in soybean growing season and its effect on soybean yield in different growth stages, based on data of daily precipitation from 60 meteorological stations during 1961 to 2018 and soybean yield in the same period, with the standardized precipitation index (SPI) as the drought and flood evaluation index. The results showed that, from 1961 to 2018, the influence range of drought in soybean growing season in Heilongjiang Province showed a weak decreasing trend, while that of flood showed a weak increasing trend. In the same period, the intensity of both drought and flood showed a weak increasing trend, with slightly stronger role of flood intensity. The probability of the co-occurrence of drought and flood accounted for 60.3%. The soybean growing season in Heilongjiang Province may become wetter. From 2012 to 2018, the influence range and occurrence intensity of flood were significantly higher than that of drought, six years of the whole or regional flood occurred, in which five years were moderate degrees. The effects of drought and flood on soybean yield differed across regions in soybean growing season. The effect of flood on soybean yield was significantly stronger than that of drought in the Northwest, North and East, and were similar in the Midland, while in the Southwest, South and Southeast, the effect of drought was much greater than that of flood. The fluctuation of soybean yield was closely related to drought and flood during bloom-seed-filling period. Among them, in the Northwest, Southwest, Midland, South and Southeast of Heilongjiang, soybean yield would reach a high level when there was a little bit more precipitation, but the moderate and above-moderate levels of flood would cause the reduction. In the North, the fluctuation of soybean yield was mainly affected by flood, while in the East, the effects of drought and flood on soybean yield were similar.

Monitoring and driving force analysis of net primary productivity in native grassland: A case study in Xilingol steppe, China

WU Ni-tu, LIU Gui-xiang, LIU Ai-jun, BAI Hai-hua, CHAO Lu-meng-qi-qi-ge

2020, 31(4):  1233-1240.  doi:10.13287/j.1001-9332.202004.014

Asbtract ( 391 )   PDF (3003KB) ( 209 )  

Grassland is an important type of terrestrial ecosystem. Using remote sensing technology to study the change and driving force of native grassland productivity at large scale is an important way to understand the ecological status of grassland. In this study, potential and actual net primary productivity (NPP) of Xilingol steppe from 2000 to 2018 were examined based on climatic model and light-use efficiency model, respectively. NPP damage value driven by human activities was calculated from the difference between potential and actual NPP. The least square method was used to analyze the temporal and spatial variation of NPP in Xilingol and the driving role of climate and human activities on NPP. The results showed that NPP in Xilingol increased from west to east, with mean annual NPP being 271.54 g C·m^-2·a^-1, the area with increased NPP (grassland restoration) being 36500 km², and the area with decreased NPP (grassland degradation) being 59900 km². The potential NPP tended to rise under the driving force of temperature and precipitation, with an average annual increase of 6.5 g C·m^-2·a^-1, which indicated that regional climate played a positive role in the improvement of NPP in Xilingol steppe, and that human activities were the main driving force for grassland degradation. The value of NPP damage driven by human activities decreased from east to west and from south to north, with the highest value in Wuzhumuqin meadow and southern steppe. Human activities, such as mining and reclamation, had the most obvious negative impact on grassland NPP.

Impacts of future climate change on spring phenology stages of rubber tree in Hainan, China

LI Ning, BAI Rui, WU Lu, LI Wei, CHEN Miao, CHEN Xin, FAN Chang-hua, YANG Gui-sheng

2020, 31(4):  1241-1249.  doi:10.13287/j.1001-9332.202004.002

Asbtract ( 422 )   PDF (1846KB) ( 248 )  

To explore the impacts of future climate change on spring phenology stages (first leaf storey expansion stage, spring flowering stage) of rubber tree in Hainan Island, we established a rubber tree spring phenology simulation model based on the crop clock model and developed a computer software RubberSP. The model simulation accuracy was examined with experimental observed phenology data. Five global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were integrated using Bayesian Model averaging method (BMA) to predict the impacts of climate change on the spring phenology of rubber tree in 2020-2099 (relative to 1986-2017) under climate scenarios of RCP2.6, RCP4.5 and RCP8.5, respectively. The results showed that the RubberSP model had good simulation accuracy, with the determination coefficient (R²) values ranging between 0.73-0.87, the root mean square error (RMSE) ranging from 3.26 to 4.15 d, and the normalized root mean square error (NRMSE) of 3.4%-7.4% between measured and simulated phenology stages. The uncertainty of a single GCM could be avoided by BMA method, which could better reflect the change trend of temperature. Temperature of Hainan Island in the end of 21 century, under the scenarios of RCP2.6, RCP4.5 and RCP8.5, would increase by more than 0.3, 1.0 and 2.5 ℃ compared with the baseline, respectively. The spring phenology stages would appear earlier and yield would increase in the future climate scenario. The time isoline of spring phenology stages would move forward to northwest, which indicated that most suitable area for rubber tree plantation in Hainan Island would expand to the northwest. The spatial difference of the first leaf storey expansion stage would be more evident, but not for spring flowering stage. The amplitude of rubber tree spring phenology variations was closely related to the increases of temperature under different RCP scenarios, with the most apparent change under RCP8.5 scenario and most mild change under RCP2.6 scenario.

Climate suitability of Ziziphus mauritiana in the main planting areas of Fujian Province, China

LI Li-chun, ZHOU Guang-sheng, CHEN Hui, YANG Kai

2020, 31(4):  1250-1258.  doi:10.13287/j.1001-9332.202004.017

Asbtract ( 398 )   PDF (1023KB) ( 254 )  

Taiwan green jujube (Ziziphus mauritiana) is a new fruit variety, with remarkable economic benefit. To achieve high quality and high yield of jujube in Fujian Province, we quantified the climate suitability model parameters of the jujube in main production areas of Fujian, and analyzed climate suitability characteristics and change trend of main production areas, based on the yield and meteorological data, combined with literature and phenological observation data and agricultural climate suitability model. The results showed that the model based on the equal weight summation method had the highest reliability. The climate suitability of jujube in main production areas of Fujian was higher, with most years being suitable or much suitable. From 1996 to 2013, the influence of climate conditions on jujube growth was generally in a good trend, which was conducive to the development of jujube production. The suitability of the main production areas in the whole growing season was ranked as temperature suitability>comprehensive climate suitability>sunshine suitability>precipitation suitability. September and October are the key period of water management. Our results are important in guiding production management and long-term planning of Taiwan green jujube in Fujian Province.

Theoretical snow period and assessment of skiing climate suitability: With Changbai Mountain Ski Resort as an example

WANG Xiu-rong, ZHAO Rong, YU Han, WANG Li-sheng, WANG Qiong

2020, 31(4):  1259-1266.  doi:10.13287/j.1001-9332.202004.013

Asbtract ( 393 )   PDF (1566KB) ( 170 )  

To analyze the climatic characteristics of snow resources and quantitatively evaluate the climatic suitability of skiing, we proposed the concept of theoretical snow period from the perspective of climate based on the synoptic principle. We set threshold values of different suitability degrees of three indices closely related to skiing, including air temperature, wind speed, and precipitation. The conversion function of each index was designed after normalization. Based on grey relational theory and Euclidean distance method, we established evaluation model of ski sports climate suitability index, with Changbai Mountain Ski Resort as an example. The results showed that snow resource in Changbai Mountain area was rich. From 1981 to 2018, the average snowfall during the theoretical snow period was 64.6 mm. Under the background of climate change, the average number of snow days and snowfall decreased slightly over the years, with the starting time of snow season being delayed and the ending time being advanced. The number of snow days in the early winter (from the starting time of snow season to the end of December) was significantly less than that in the later winter (from the next January to the end of snow season). Climate in Changbai Mountain was highly suitable for skiing during the snow period. The most suitable and relatively suitable days with respect to air temperature, wind speed and precipitation accounted for 91.9%, 91.8%, and 94.6% of the total, respectively. The cumulative number of days for ski comprehensive weather suita-bility accounted for 99.7%, indicating that most days were suitable for skiing. The concept of theoretical snow period in this study had made up for the problems caused by the lack of meteorological observation data of the first and last snow event on the study of snow resources. The climate suitabi-lity evaluation model of skiing could help make management decision for the development and operation of ski resorts and scientific support for skiing enthusiasts.

Spatial and temporal responses of habitat quality to urbanization: A case study of Changchun City, Jilin Province, China

BAI Li-min, FENG Xing-hua, SUN Rui-feng, GAO He

2020, 31(4):  1267-1277.  doi:10.13287/j.1001-9332.202004.012

Asbtract ( 508 )   PDF (4385KB) ( 310 )  

Habitat quality is an important index to evaluate regional ecological security. Revealing its spatial and temporal responses to urbanization is conducive to the in-depth implementation of new urbanization. Based on land use data, we analyzed the spatio-temporal characteristics of Changchun’s landscape pattern, habitat quality and its sample zone from the grid scale with comprehensive utilization of spatial analysis and ecological model analysis. We further discussed the responses of habitat quality during urbanization. The results showed that the low values of patch density (PD), edge density (ED) and Shannon diversity index (SHDI) were distributed in the western plains, while the high aggregation index (AI) showed a patchy distribution in eastern and southern of the city. During 2000-2015, the habitat quality of Changchun showed a trend of degradation and significant spatial heterogeneity, showing a distribution of “high in the east, and low in the west”. The expansion of construction land and the transportation infrastructure played a leading role in the degradation of regional habitat quality. The changes of habitat quality differed significantly in different zones. The overall variation of water belt was relatively small, while the variation frequency and amplitude of mountain, urban expansion, and traffic belt were relatively high. Natural factors including slope and elevation basically shaped the overall distribution pattern of habitat quality in Changchun, while urbanization factors including population density, GDP and night light index showed significant negative correlation with habitat quality. To alleviate the ecological pressure of urbanization and promote habitat quality, we proposed differentiated development strategies, such as preventing deforestation in the Dahei Mountains, using ecological strategies to restore habitat degradation areas, improving land use efficiency in built-up urban areas, promoting “smart growth” in urban areas, setting red line of farmland in hilly areas, and strengthening ecological infrastructure construction.

Tradeoffs and synergies of ecosystem services in western mountainous China: A case study of the Bailongjiang watershed in Gansu, China

GONG Jie, LIU Dong-qing, GAO Bing-li, XU Cai-xian, LI Yan

2020, 31(4):  1278-1288.  doi:10.13287/j.1001-9332.202004.019

Asbtract ( 379 )   PDF (4917KB) ( 353 )  

The Bailongjiang watershed of Gansu is an important water conservation and ecological barrier area in the upper reaches of Yangtze River. It is necessary to reveal the tradeoffs and synergies of ecosystem services (ESs) for the “win-win” of watershed ecological system and social eco-nomy development. Based on the InVEST model, four typical ESs including soil conservation (SC), water conservation (WC), food supply (FS), and habitat quality (HQ) were assessed, and the multi-scale tradeoffs and synergies of ESs and its drivers were analyzed by correlation and root mean square deviation (RMSD). The results showed that there were significant synergies among SC, WC, and HQ, and a significant tradeoff between FS and HQ, SC, WC, respectively. The areas with high tradeoff intensity between the three pairs of synergistic services (SC-WC, SC-HQ, WC-HQ), and between FS and HQ were mainly concentrated in the steep forest area of middle-high mountain in Wenxian, Diebu and Zhouqu. The high intensity of tradeoffs between FS-SC, FS-WC were mainly concentrated in the gentle apricus farming and pastoral areas of middle-low mountain in Tanchang and Wudu. The spatial variation of land use/cover caused by human activities was an important factor affecting the degree of ES tradeoffs and its scale effect.

Monitoring and evaluation of eco-environmental quality of lake basin regions in Central Yunnan Province, China

ZHU Hong, WANG Jin-liang, CHENG Feng, DENG Huan, ZHANG En-wei, LI Ying-xin

2020, 31(4):  1289-1297.  doi:10.13287/j.1001-9332.202004.011

Asbtract ( 449 )   PDF (1579KB) ( 168 )  

The basin region of nine highland lakes plays an important role in the economic development of Yunnan Province, in which, the basin region of the five lakes (Dianchi, Fuxianhu, Xingyunhu, Qiluhu and Yangzonghai Lake, hereinafter was called Five-lake Basin) locating in the central region of Yunnan Province is the most active economic and social development area of industry, agriculture and tourism, closely related to the eco-environmental quality of the whole basin. In this study, the eco-environmental quality of the Five-lake Basin from 1988 to 2018 was monitored and evaluated based on remote sensing ecological index (RSEI). The results showed that although the eco-environmental quality in this area had a trend of turning better from 1988 to 2018, with the mean value of RSEI increasing from 0.368 to 0.481, whereas the overall eco-environmental quality of the basin was poor. The area with improved eco-environmental quality accounted for 57.6%, which was mainly distributed in the mountains between lakes, while the declining area was mainly the flat area around the lake. The eco-environmental quality of Dianchi Lake, Fuxianhu Lake, and Yangzonghai Lake was improved during the study period, but the eco-environmental quality of Qiluhu Lake and Xingyunhu Lake deteriorated obviously in the last 10 years. The change of eco-environmental quality in each lake was consistent with the change of water quality. In the future, the improvement of eco-environmental quality needs more social attention and government investment.

Effects of arbuscular mycorrhizal fungi on metabolism of aroma substances in tobacco

ZHAO Fang-gui, QU Feng, CHE Yong-mei, YAO Jia-lin, LIU Xin

2020, 31(4):  1298-1304.  doi:10.13287/j.1001-9332.202004.031

Asbtract ( 399 )   PDF (1138KB) ( 300 )  

Arbuscular mycorrhizal fungi (AMF) can promote nutrient absorption and improve stress resistance of host plants. The effects of AMF on aroma substance metabolism were rarely examined. In this study, we investigated the effects of AMF (Glomus mosseae) on glands and metabolism of aroma substances in tobacco leaves. The results showed that the density of gland hair and the relative expression of the glandular-specific lipid transporter gene NtLTP1, which was necessary to induce lipid secretion, were higher in the leaves of tobacco inoculated with AMF. The content of main aroma substances in tobacco leaves, such as carotenoids, chlorogenic acid and solanesol, were increased. Moreover, AMF inoculation increased the activities of phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO), the key aroma substance synthesis enzymes, and caused upregulation in the relative expression of phenylalanine transaminase, polyphenoloxidase, flavonoids alcoholase and squalene synthase encoding genes. In all, the symbiosis with G. mosseae could increase the abundance and secretory activity of glandular hairs and promote the synthesis of aroma substances in tobacco leaves.

Effects of salt and drought stresses on rhizosphere soil bacterial community structure and peanut yield

XU Yang, ZHANG Guan-chu, DING Hong, CI Dun-wei, QIN Fei-fei, ZHANG Zhi-meng, DAI Liang-xiang

2020, 31(4):  1305-1313.  doi:10.13287/j.1001-9332.202004.036

Asbtract ( 451 )   PDF (1877KB) ( 306 )  

A pot experiment with Huayu 25 as experimental material was conducted, with treatments of drought and salt stresses. The effects of drought and salt stresses at the flowering stage on the plant morphology, pod yield, and soil bacterial community structure in the rhizosphere were examined. The results showed that Proteobacteria, Actinobacteria, Saccharibacteria, Chloroflexi, Cyanobacteria, and Acidobacteria were the dominant phyla in the rhizosphere soil of peanut. Compared with that under normal conditions, the relative abundance of Proteobacteria and Actinobacteria dramatically decreased, while that of Cyanobacteria evidently increased in drought-treated and salt-treated soil. Moreover, the variation of Cyanobacteria abundance caused by combined drought and salt stresses was stronger than that caused by single drought or salt stress. Functional meta-genomic profiling indicated that a series of sequences related to signaling transduction, defense mechanism and post-translational modification, protein turnover, chaperones were enriched in rhizosphere soil under stressed conditions, which might have implications for plant survival and stress tolerance. Drought and salt stress affectedpeanut growth and reduced pod yield. Results from this study would present reference on the future improvement of stress tolerance of peanuts via modifying soil microbial community.

Short-term response of carbon emission to snow cover change in Calamagrostis angustifolia wetlands of Sanjiang Plain, Northeast China

ZHANG Rong-tao, FU Xiao-yu, WANG Kang, LIU Ying-nan, FU Xiao-ling, NI Hong-wei

2020, 31(4):  1314-1322.  doi:10.13287/j.1001-9332.202004.035

Asbtract ( 375 )   PDF (1503KB) ( 157 )  

To understand the response of Calamagrostis angustifolia wetland of the Sanjiang Plain to changes in snow cover, we examined the greenhouse gases emission flux of the removed snow treatment (0 cm, RS), the added snow treatment (50 cm, AS) and the control (20 cm, CK) of a C. angustifolia wetland, and their relations with environmental factors with the method of the static chamber-gas chromatography. The results showed that soil temperature, soil water content, and carbon emissions were lowest during the snow-covering period under all treatments, and gradually increased with time. With the increases of time and snow thickness, soil temperature was rised and the difference of three treatments gradually was decreased. Soil water content of RS was always lower than that of CK and AS. AS and CK could promote soil CO₂ emission compared with RS during and after snowmelt. The soil cumulative CH₄ emissions differed little among the treatments. There was significant correlation between soil temperature and cumulative CO₂ and CH₄ emissions. With the increases of soil temperature, soil cumulative CO₂ emission continued to increase and soil cumulative CH₄ emission decreased firstly and then increased rapidly. Soil water content was significantly correlated with cumulative CO₂ and CH₄ emissions. As the soil moisture increased, the cumulative soil CO₂ emission gradually increased, reaching a certain threshold and then flattening, while soil cumulative CH₄ emission continuously increased.

Soil amelioration of different vegetation types in saline-alkali land of the Yellow River Delta, China

SUN Jia, XIA Jiang-bao, SU Li, ZHAO Xi-mei, CHEN Yin-ping, YUE Xi-yuan, LI Chuan-rong

2020, 31(4):  1323-1332.  doi:10.13287/j.1001-9332.202004.032

Asbtract ( 566 )   PDF (992KB) ( 183 )  

Yellow River Delta is an important distribution area of coastal saline-alkali land in China. Revegetation is the main technology for ecological restoration during saline-alkali land amelioration. To explore the effects of different vegetation types on soil improvement in saline-alkali land and get the suitable model in the Yellow River Delta, four tree-grass compound models, Salix americana+Distichlis spicata, S. matsudana+D. spicata, Tamarix chinensis+Medicago sativa, and Fraxinus chinensis+T. chinensis+M. sativa, were set up, with pure S. americana forest as the control. Twenty indicators, including soil moisture physical parameters, saline-alkali content, soil nutrient contents, and microorganism quantity etc. were measured. Principal component analysis, cluster analysis and fuzzy mathematics were used to evaluate soil modification effect of different vegetation combinations. The results showed that all compound models significantly improved soil physical and che-mical properties in coastal saline-alkali land by increasing soil porosity, soil water storage, soil organic matter content, available nutrient content and soil microorganism quantity and reducing soil density. Among all the models, the tree-shrub-grass mixed model of F. chinensis+T. chinensis+M. sativa was the most effective in inhibiting salt and alkali stress and increasing soil nutrients and microorganism abundance, whereas the tree-grass mixed model of S. matsudana+D. spicata was the most effective in improving soil water physical properties. The combined effects of different vegetation patterns on soil amelioration in coastal saline-alkali land of the Yellow River Delta were arranged in order of F. chinensis+T. chinensis+M. sativa> S. matsudana+D. spicata> S. americana+D. spicata> T. chinensis+M. sativa.

Adaptation of Suaeda salsa to water/sediment conditions and nitrogen input in tidal flat wetlands in the Yellow River Delta, China

SONG Hong-li, HAN Hong-jun, YU Wan-ni, WANG Li-zhi

2020, 31(4):  1333-1340.  doi:10.13287/j.1001-9332.202004.039

Asbtract ( 309 )   PDF (1595KB) ( 341 )  

The application of Water-Sediment Regulation Project provides abundant freshwater for the Yellow River Delta, changes water and sediment condition, as well as brings lots of exogenous substances. Using orthogonal test with three factors and four levels, we examined the effects of water condition, sediment burial depth and exogenous nitrogen input on the growth of wetland plant, Suaeda salsa. The results showed that sediment burial had great effect on protein content and SOD activity. Nitrogen input had great effect on POD activity. CAT activity was not affected by sediment burial, nitrogen input and water depth. The water depth manipulation had significant effect on leaf, stem and total dry weight. With the increases of water depth, leaf, stem and total dry weight showed a decreasing trend, with the maximum values (25.70, 40.86, 69.73 g) at the 2 cm water depth. There was no effect of nitrogen input and sediment burial on dry weight. The results of range analysis showed that the effect of water depth on leaf, stem, root and total dry weight was great, and followed by nitrogen input and sediment burial, with an optimal combination of 2 cm water depth +12 cm sediment burial + 9 g·m^-2 nitrogen input. These findings suggested that water condition played a decisive role in affecting the growth of S. salsa. Consequently, more attention should be paid to the control of water depth in the process of water and sediment regulation.

Distribution characteristics of heavy metals in soil and its influence on greening plants in a main road of Lanzhou City, Northwest China

XU Yu-ling, FENG Gong-li, JIANG Xiao-yu, LIU Na, LI Jia-min, LI Gui-ying, YANG Ying-li

2020, 31(4):  1341-1348.  doi:10.13287/j.1001-9332.202004.040

Asbtract ( 354 )   PDF (546KB) ( 195 )  

To investigate the characteristics of heavy metal pollution caused by traffic and its potential ecological risks, we measured the amount of metal elements in samples collected from a traffic trunk road in Lanzhou City with atomic absorption spectrophotometer. The single factor index method and potential ecological risk index method were used to evaluate the degree of pollution and potential ecological risks, and then the effects of heavy metal pollution on chlorophyll and calcium (Ca) contents in greening plants were analyzed. The results showed that the amount of heavy metals including chromium (Cr), manganese (Mn), zinc (Zn), copper (Cu) and nickel (Ni) in the soils increased significantly, with Cr, Cu and Pb reaching moderate pollution level. The degree of potential ecological risk was Cu>Pb>Cr>Ni>Zn>Mn. Sophora japonica, Rosa chinesis, Prunus ceraifera, and Euonymus japonicas showed different accumulation effects on Pb, Mn, Zn, and Ni. The content of chlorophyll in the leaves of deciduous species S. japonica, R. chinesis and P. ceraifera was higher in the roadside sampling point than that in the control point, while the pattern was just the opposite in evergreen species E. japonicas and P. orientalis. Foliar Ca content of greening plants in the roadside sampling point was higher than that in the control point, suggesting that high chlorophyll and Ca contents might be beneficial to plant survival in the heavy metal contaminated area. Taken together, traffic operation led to the accumulation of heavy metals (Cr, Mn, Zn, Cu, and Ni) in the soil of the study area. S. japonica, R. chinesis, P. ceraifera and E. japonicas could accumulate Pb, Mn, Zn and Ni, which could be used as greening plants in soils polluted by those heavy metals.

Effects of soil permeability improvement and purification of pollutants in urban green space under different matrix composition amendments

HAO Shan, WANG Chen-guang, ZHANG A-feng, WANG Xu-dong, MA Xiao, MA Yue

2020, 31(4):  1349-1356.  doi:10.13287/j.1001-9332.202004.037

Asbtract ( 425 )   PDF (1048KB) ( 230 )  

Green land is important carrier in cities. We investigated the effects of soil permeability improvement and purification of pollutants under different matrix composition amendments in Xixian New Area, Shaanxi Province. Six materials, including biochar, vermiculite, perlite, compost, polyacrylamide (PAM) and coir, were mixed with basic materials that were composed of soil and sand (volume ratio of 4:4), and then incubated for 30 days. We analyzed bulk density, saturated hydraulic conductivity, saturated moisture, and total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), copper (Cu), zinc (Zn), cadmium (Cd) concentrations in pollutants. For biochar and compost with volume ratio of 0.5:1.5 (Ⅰ) and 1:1 (Ⅱ), 1%PAM application had the best effect on soil permeability (including bulk density, saturated hydraulic conductivity, and saturated moisture). The effect purification of TN and COD was better under the condition of biochar and compost (Ⅰ) with 0.5% PAM amendment than that with 1% PAM amendment. Under biochar and compost (Ⅰ) with 1%PAM treatment, the adsorption rate of Zn, Cd, Cu was 99.9%, 99.7%, and 97.2%, respectively. In general, biochar and compost (volume ratio of 0.5:1.5) with 1% PAM could be recommended as the media of the sponge city green land in Xixian New Area.

Establishing potential habitats of Mytilopsis sallei with Maxent niche model

MA Hong-mei, QIN Chuan-xin,WANG Xing-qiang , ZHU Wen-tao,YIN Cheng-hao,XI Shi-gai, ZUO Tao, PAN Wan-ni

2020, 31(4):  1357-1364.  doi:10.13287/j.1001-9332.202004.038

Asbtract ( 403 )   PDF (2159KB) ( 309 )  

Mytilopsis sallei, an invasive alien species, has strong reproductive ability and high adaptability. It can severely endanger biodiversity of intertidal ecosystem after invasion. The intertidal zones and oyster breeding areas in some coastal areas of Guangdong Province have been severely invaded by M. sallei. To examine the potential habitat of M. sallei in China, we established a potential habitat prediction model of M. sallei using Maxent and ArcGIS method for China and global scales. The model was verified by the method of receiver operating characteristic curve (ROC) analysis and field investigation. The results showed that M. sallei could distribute with high probabili-ty in the area between North and South America, South India in Asia, Sri Lanka, the south coast of the Yangtze River in China, and in Van Dimen Bay of the southern hemisphere. In China, M. sallei mainly distributed in coastal provinces south of Shanghai. The main environmental factors affecting the suitable distribution areas for M. sallei were water vapor pressure, temperature, and solar radiation. After ROC detection, the AUC values of both the training and testing sets were 0.996, indicating that the prediction reached an excellent level. Our results provide theoretical basis for the risk assessment and management of M. sallei, and complement the potential habitat prediction of invasive species in China.

Characteristics of soil microbial and nematode communities under artificial Medicago sativa grasslands with different cultivation years in semi-arid region of Loess Plateau, Northwest China

GENG De-zhou, HUANG Jing-hua, HUO Na, WANG Nan, YANG Pan-pan, ZHAO Shi-wei

2020, 31(4):  1365-1377.  doi:10.13287/j.1001-9332.202004.034

Asbtract ( 417 )   PDF (1335KB) ( 143 )  

The establishment of Medicago sativa artificial grasslands is an important practice of grassland vegetation restoration in the Loess Plateau. Understanding community characteristics of soil microbes and nematodes can provide important information for evaluating and controlling ecolo-gical and environmental effects of vegetation restoration. In this study, we used M. sativa artificial grasslands with four different cultivation years (1, 2, 6 and 12 years) in southern Ningxia mountainous region, with a farmland and a natural grassland as control, to explore changing trends of the two biological communities during artificial grassland restoration in semi-arid region of the Loess Plateau. The results showed that: 1) After the conversion of farmland to M. sativa grassland, Chao1, ACE and Shannon diversity indices of soil bacterial community increased firstly and then decreased, which reached the maximum after six years of M. sativa grassland establishment. For soil fungal community, Shannon diversity index was lower in 6 and 12 year-old M. sativa grasslands than in the other two artificial grasslands, and the community composition differed across restoration years. 2) With the increases of restoration years, the abundance of soil nematodes showed a similar changing trend with Shannon diversity index of bacterial community. The composition of nematode community did not greatly differ between the 6-year-old M. sativa grassland and farmland, while that in 12-year-old artificial grassland was more similar to that in natural grassland. The proportion of bacterivorous and plant-feeding nematodes, as well as plant parasitic index and nematode channel index of nematode community,were increased, while the proportion of fungivores and omnivores-predators and maturity index were decreased. 3) During the restoration, changes in soil organic carbon, total nitrogen and available phosphorus greatly affected soil microbial community, which could further influence soil nematode community. There were significant correlations between dominant microbial phyla and trophic groups of soil nematodes, implying the possible effects of soil microbes on nematode community. In M. sativa artificial grassland with different establishment years, changes in plant biomass and diversity might significantly affect soil nematode and microbial communities through affecting their food conditions.

Reviews

Non-structural carbohydrate content of trees and its influencing factors at multiple spatial-temporal scales: A review

DU Jian-hui, SHAO Jia-yi, LI Sheng-fa , QIN Jing

2020, 31(4):  1378-1388.  doi:10.13287/j.1001-9332.202004.001

Asbtract ( 561 )   PDF (605KB) ( 337 )  

Non-structural carbohydrates (NSC) are essential substances for the tree growth and metabolism, and play an important role in environmental adaptation of trees. At temporal scale, NSC contents in trees have limited inter-annual variation, which could be attributed to the strategy of tree growth and carbon storage. Different factors influence NSC contents of trees in various climatic regions, which change substantially at the seasonal scale. At spatial scale, the variations of NSC content in trees show an insignificantly decreasing trend with the decreases of latitude at global and continental scales, which are mainly related to the hydrothermal gradients. The trend at regional scale is opposite because of the decrease of hydrothermal gradients and lower sample frequency. More sophisticated relations exist between the variations of NSC content in trees and altitudes, which are caused by species-specific characteristics and the variations of micro-habitat conditions. The variations of NSC content in trees at multiple spatial-temporal scales are generally determined by both biotic and abiotic factors, which are mainly dependent on the tradeoff among photosynthate production, respiratory depletion, and tree growth. Furthermore, the methods used for the determination of NSC content are different, which results in great uncertainties in comparing conclusions from different studies. The methods used for sample collection and measurement of NSC should be improved and unified to enhance the comparison among different studies. The NSC contents of trees in different age classes should be measured with all organs collected at multiple spatial-temporal scales. The underlying mechanisms, significance of NSC storage, transformation and allocation on tree growth and survival should be further discussed.

Ecosystem service function of green manure and its application in dryland agriculture of China

FAN Zhi-long, CHAI Qiang, CAO Wei-dong, YU Ai-zhong, ZHAO Cai, XIE Jun-hong, YIN Wen, HU Fa-long

2020, 31(4):  1389-1402.  doi:10.13287/j.1001-9332.202004.023

Asbtract ( 677 )   PDF (760KB) ( 337 )  

Dryland agriculture, with wide distribution and high yield potential, plays an important role in ensuring food security in China. It is currently limited by water scarcity, soil depletion, water and soil loss, and low non-renewable resource-use efficiency. Green manure has the potential to improve growth environment of crops and promote sustainable high-yield crops by increasing soil quality, balancing soil nutrients, and enhancing soil water-storage capacity. In addition, green manure has ecological benefits, including enhancing agroecosystem biodiversity, increasing soil surface cover degree, reducing ineffective nutrient loss to environment, improving air balance of farmland systems, and biological control of diseases, insect pests, and weeds. Under current scenario of intensified global climate change, environmental deterioration, and agricultural product demand changes, the traditional agronomic techniques of using green manure as a fertilizer cannot satisfy the requirements of agricultural development. Thus, it is necessary to strengthen the selection and bree-ding of green manure genetic resources for dryland agriculture, to develop a new regionalization of green manure, and to establish a cropping pattern based on green manure suitable for different regions. Furthermore, it is important to study and optimize the tillage and cultivation techniques to satisfy modern production and to establish an evaluation system for the comprehensive benefits of green manure. It is needed to establish a green manure application pattern that enables resource and ecological protection for improving ecological environment and economic efficiency of dryland agriculture and provides theoretical basis and technical support for exploiting green manure benefits.

Effects of organic manure on soil nutrient content: A review

GONG Xue-jiao, QIN Lin, LIU Fei, LIU Dong-na, MA Wei-wei, ZHANG Ting, LIU Xiao, LUO Fan

2020, 31(4):  1403-1416.  doi:10.13287/j.1001-9332.202004.025

Asbtract ( 566 )   PDF (689KB) ( 305 )  

To be green and sustainable are essential requirements for modern agriculture in China, with fertilizer input being one of the keys. Developing and extending organic fertilizer has become a basic national policy for agricultural production in China for its eco-friendly and advantages in fertile farmland nurture. Organic fertilizer has wide source and variety. The conditions for agricultural production are also largely different. We analyzed the status of organic fertilizer products and stan-dards, physical and chemical properties differences, differences of carbon and nitrogen mineralization characteristics and their influencing factors. Meanwhile, we reviewed the effects of application of organic fertilizer on basic soil fertility of cultivated land. Due to the differences in source and production process, different organic fertilizers differ in the four main internal factors (the content of organic carbon fractions, total N, active nitrogen and C/N) affecting carbon and nitrogen mineralization characteristics, including mineralization rates and the amount of available nitrogen release. With the influence of external conditions such as edatope, different organic fertilizers vary in nutrient supply characteristics. Overall, organic fertilizer significantly increases soil organic matter content, especially for labile organic matter content and carbon management index (CMI). Moreover, soil contents of nitrogen, phosphorus and potassium are expanded. As a result, nutrient loss caused by crop growth is reduced, with positive consequences on soil quality. The application of organic fertilizer on fertile farmland nurture, the theoretical study of organic fertilizer, and the development of safe and efficient organic fertilizer products should be strengthened in the future, promoting the efficient recycling of organic fertilizer resources which could be an important agricultural resource.

Assessing the “two water worlds” hypothesis by stable isotope method: Progress and prospect

ZHAO Ying, WANG Li

2020, 31(4):  1417-1424.  doi:10.13287/j.1001-9332.202004.015

Asbtract ( 607 )   PDF (1053KB) ( 382 )  

According to the two water worlds hypothesis (TWW), there are two independent water pools with different functions in the soil matrix, bound water world used by plants and mobile water world contributed to runoff and groundwater recharge. The TWW hypothesis is different from the original hydrological model that soil water is completely mixed, and is of significance for establishing new hydrological models. Currently, the theorical basis and formation conditions of TWW hypothesis are still unclear, with less reaserch from China. Here, we summarized research process, discrimination method, controversial points and prospect of TWW hypothesis. There are three views regarding the hypothesis: support, partial support, and rejection. All evaluation methods are based on hydrogen and oxygen isotope (²H, ¹⁸O) methods, such as direct comparison, precipitation intersection point method, precipitation residual method, and precipitation migration method. The representativeness of isotope samples of bound water and mobile water and the limitation of isotope technology may be the important reasons for different results across all the studies. The development of methods different from stable isotope ones is an important direction of future research. In addition, the theoretical basis of TWW hypothesis remains unclear, which is the most critical issue. The hypothesis is about a continuous ecological hydrological process coupling of precipitation, soil, and vegetation. Multi-disciplinary integration, multi-scale assessment and multi-factor analysis would be the effective ways to study this hypothesis, and would be an important research direction in the field of hydrology and ecology.