Table of Content

20 July 2008, Volume 19 Issue 07

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Articles

Species richness patterns of Picea schrenkiana var. tianschanica communities along an altitudinal gradient at different longitudes in Xinjiang of Northwest China.

LIU Gui-feng^1，2; ZANG Run-guo¹;GUO Zhong-jun³;AYOUFU Bahaerguli³;ZHANG Xin-ping³;CHENG Ke-wu⁴;BAI Zhi-qiang³

2008, 19(07):  1407-1413 . 

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The Picea schrenkiana var. tianschanica forest in Zhaosu, Gongliu, Wusu, Urumqi and Hami that covered about 12 longitudes (81°05′-93°415′E) along the Tianshan Mountains was investigated by using vertical transects to analyze the species richness of the forest along an altitudinal gradient at different longitudes. The results showed that at most longitudinal positions, P. schrenkiana var. tianschanica forest was basically of pure forest, with P. schrenkiana var. tianschanica as the dominant species, very few of other arbor and shrub species, and the species richness of herbs being controlled by the growth of P. schrenkiana var.tianschanica. This forest had the widest distribution, highest canopy density, best growth, and highest stand volume at middle altitudes, resulting in the lowest species richness of herbs. The herb species richness in P. schrenkiana var. tianschanica forest in Tianshan Mountains showed an inverse hump-shaped variation along the altitude, which could be described by the quadratic equation y=ax²-bx+c (a, b, c＞0).

Spatial patterns of different age-class individuals in Pinus tabulaeformis forest in Songshan Nature Reserve of Beijing, China.

NIU Li-lilYU Xin-xiao;YUE Yong-jie

2008, 19(07):  1414-1418 . 

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By the method of point pattern analysis, this paper studied the spatial patterns of different age-class individuals in the Pinus tabulaeformis forest in Songshan Nature Reserve of Beijing, and the spatial association between the individuals. The results showed that there existed greater differences in the densities of different age-class P. tabulaeformis individuals, e.g., ageclass I had the density of 15 plants per hectare, while age-class Ⅲ had the density of 924 plants per hectare. The spatial patterns of different ageclass individuals and the spatial association between the individuals had a close relationship with the spatial scale. In the scale of <40 m, the individuals of all age-classes tended to clump, and there was a stronger spatial association between the individuals of different age-classes. When the scale was larger than 30 m or 40 m, the individuals of all age-classes would disperse randomly, and their spatial association would be weakened greatly.

Carbon storage and its allocation in mixed alder-cypress plantations at different age stages.

WU Peng-fei^1,2,3;ZHU Bo¹;LIU Shi-rong³;WANG Xiao-guo¹

2008, 19(07):  1419-1424 . 

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The 10-, 15-, 20- and 25-year-old mixed alder (Alnus cremastogyne)cypress (Cupressus funebris) plantations and the 30-year-old pure cypress plantation succeeded from mixed alder-cypress plantation in the hilly area of central Sichuan Basin were chosen as test objects to study the dynamic changes and allocation patterns of their carbon storage. The results showed that the vegetation carbon storage in mixed aldercypress plantations increased continually from the age stage of 10- to 30-year, and reached 52.40 t·hm^-2 at the age stage of 30-year. The vegetation carbon storage of arbor layer at each age stage was more than 85.59% of the total, and the soil carbon storagewithin 0-40 cm layer increased significantly (P<0.05) from the age stage of 10- to 15-year, with the maximum (84.79 t·hm^-2) atthe age stage of 15-year, but decreased significantly (P<0.05) from the age stage of 15- to 25-year and tended to stable from the age stage of 25- to 30-year (P>0.05). The carbon storage of the mixed alder-cypress plantations increased significantly from the age stage of 10- to 15-year, with the maximum (118.13 t·hm^-2) at the age stage of 15-year, but declined from the age stage of 15- to 25-year while increased slightly from the age stage of 25- to 30-year. The proportion of vegetation carbon storage increased continually from the age stage of 10- to 30-year, whereas that of soil carbon storage was in adverse. Comparing with other types of plantations in China, mixed alder-cypress plantation had a lower storage of carbon.

Responses of Jatropha curcas L. seedlings to drought stress.

DOU Xin-yong¹;WU Guo-jiang²;HUANG Hong-ying^1,3;HOU Yu-jia¹;GU Qun⁴; PENG Chang-lian¹

2008, 19(07):  1425-1230 . 

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By adding different concentrations (5%-25%) of polyethylene glycol (PEG) into Hoagland solution to simulate a gradient of drought stress, the photosynthetic characteristics and drought resistance of Jatropha curcas L. seedlings were investigated. The results showed that when treated with lower concentrations (≤15%) of PEG, the photosynthetic rate (P_n), stomatal conductance (G_s), and intercellular carbon dioxide concentration (C_i) of the seedlings decreased with increasing PEG concentration, while the hlorophyll fluorescence parameters optimal/maximal quantum yield of PSⅡ(F_v/F_m) decreased slightly and minimal fluorescence (F_o) was almost unaltered. The certain reduction of actual photochemical efficiency of PSⅡin the light (Φ_PSⅡ), coefficient of photochemical quenching(q_P), and apparent electron transport rate (ETR) was associated with a significantincrease in non-photochemical quenching (NPQ), whereas as the PEG concentration was increased to higher than 15%, C_i increased remarkably, P_n，G_s and WUE had a sustained decrease, while F_v/F_m,Φ_PSⅡ,q_P and ETR decreased more significantly, F_o increased rapidly, and NPQ decreased. The reduction of P_n under low concentration PEG was mainly due to stomatal limitation, while that under high PEG concentration was referred to the combination of non-stomatal and stomatal limitation. When the PEG concentration was lower than 20%, P_n decreased but photosynthetic structure was not damaged. The recovery of PSⅡ activity and the survival of plant were found after the severe drought stress was removed 15 days later. It was concluded that Jatropha curcas had stronger tolerance to drought stress.

Characteristics of gas release during combustion of main arbor and shrub species in Xiaoxing’an Mountain.

HU Hai-qing;LI Ao-bin

2008, 19(07):  1431-1436 . 

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The amounts of CO₂, CO, CxHy, SO₂ and NO released from the combustion of 10 arbor and 9 shrub species in Liangshui Forest Farm of Xiaoxing’an Mountain were determined, with the release amounts and emission factors of these gases calculated. The results showed that the released CO₂, the total amount of carbon-containing gases, and the mean value of the total amount of the 5 gases during combustion were larger for arbors than for shrubs, being 1 277.04 and 1 149.06 mg·g^-1, 1 476.27 and 1 147.18 mg·g^-1, and 1 486.21 and 1 459.67 mg·g^-1, respectively, while an opposite pattern of the mean release of CO, NO and SO₂ was observed, being 231.58 and 282.93 mg·g^-1, 3.61 and 5.03 mg·g^-1, and 6.32 and 7.46 mg·g^-1 for the arbor and shrub species, respectively. The emission factors of CO₂ and CO were also larger for arbors than for shrubs, being 2.8853 and 2.7718, and 0.4558 and 0.2425, respectively.

Application of 3D visualization software in forest ecosystem management in eastern Liaoning mountainous region.

LENG Wen-fang¹;DAI Li-min¹;HE Hong-shi^1,2;YU Da-pao¹;ZHOU Li¹

2008, 19(07):  1437-1442 . 

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By using 3D visualization software WCS 6.0, the virtual forest landscape of Pulepu Town in eastern Liaoning mountainous region was onstructed, and the dynamic changes of forests under four different management scenarios, i.e., enclosing undeveloped forest, small area clear-cutting, selective-logging, and two-step progressive logging, were modeled. The results showed that under enclosure, 10-30 years old Larix olgensis var. changpaiensis grew faster (ca. 0.6 m·a^-1), while 10-30 years old Quercus mongolica grew slower (ca. 0.4 m·a^-1). Small area clear-cutting had the greatest effects on the forests, followed by two-step progressive logging, and low intensity selective-logging. The WCS software could visually display the outcomes of different scenarios, which would benefit the decisionmaking in forest management.

Nutrient contents and resorption characteristics in needles of different age Pinus massoniana (Lamb.) before and after withering.

LI Rong-hua^1,3;WANG Si-long^1,2;WANG Qing-kui^1,2

2008, 19(07):  1443-1447 . 

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Taking the 10-, 23-, and 45-year-old -Pinus massoniana- plantations in Huitong of Hunnan Province as test objects and with the parameters nutrient content per unit needle mass, nutrient content per unit needle length, and nutrient content of single needle, the nutrient contents and resorption characteristics in the needles of different age P. massoniana before and after withering were studied. The results showed that after withering, the mass of single needle, length of single needle, and mass per unit needle length were decreased by 15.9%, 4.6% and 13.9%, respectively. The nutrient contents in the needles differed with the age of P. massoniana, and the mean resorption of N, P and K in the needles was all higher than 50%. With the increase of tree age, the nutrient resorption efficiency and proficiency increased first and declined then. According to the calculations with the parameters mentioned above, there was no significant difference in the resorption efficiency of the nutrients except N.

Effects of soil salt on the niche of main plant species in alpine meadow.

WANG Xin^1,2;HU Yu-kun¹;Rehemudula Adilla¹;LIU Yan-yan^1,2;LI Kai-hui¹;WANG Ji-yun³

2008, 19(07):  1448-1454 . 

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By using Levins niche breadth index and Cowell similarity index, the niche breadth and niche similarity of main plant species in Bayanbulak alpine meadow were calculated, based on 3 resources dimensions (soil moisture, organic matter, and available K) along four gradients of soil salt content. The results showed that with the increase of soil salt content, the average niche breadth of main constructive species Carex stenocarpa based on the 3 resources dimensions decreased from 0.4433 to 0.1740, while that of companion species Potentilla anserina increased from 0.1263 to 0.2215, indicating that the niche breadth of the species with low salt-endurance decreased gradually, while the species with relatively high saltendurance had an increasing niche breadth, being-able to be an important succession species. With the increase of soil salt content, the niche similarity between the species with low salt-endurance increased, while that between the species with high salt-endurance was in adverse. The niche similarity between C. stenocarpa and Kobresia capillifolia increased from 0.701 to 0.842, and that between P. anserina and Taraxacum pseudolpinum decreased from 1 to 0.708. The difference in biological characters among plant species should be the main reason for their different responses to soil salt content.

Variation patterns of Coptis teeta biomass and its major active compounds along an altitude gradient.

ZHANG Ji^1,2;CAI Chuan-tao¹;CAI Zhi-quan¹;LIU Gui-zhou¹; LUO Yuan¹;YANG Zhi-xiong³

2008, 19(07):  1455-1461 . 

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An investigation was made on the biomass and major active compounds of wild and cultivated Coptis teetaalong an altitude gradient in Nujiang of Yunnan. The results showed that the rhizome and root biomass of wild C. teeta increased from the altitude 2 100 m to 2 700 m, but the difference was not significant. The rhizome biomass of cultivated C. teeta was 87.5 kg·hm^-2 at 2 600 m and 97.0 kg·hm^-2 at 2 700 m, being much higher than 34.8 kg·hm^-2 at 2 300 m (P<0.05). At the same altitudes (2 300 m, 2 600 m, and 2 700 m), cultivated C. teeta had higher rhizome and root biomass than wild C. teeta, but the difference was not significant. There was a significant positive correlation between the rhizome and root biomass and the whole plant biomass of wild C. teeta. Wild C. teeta had the highest content of berberine in rhizome (4.60%) and root (1.93%) at 2 700 m, plamatinein in rhizome, and jatrorrhizine in rhizome and root at 2 600-2 700 m, and plamatinein in root at 2 300 m; while cultivated C. teetahad the highest content of berberine in rhizome (4.41%) and root (1.90%) at 2 600 m, plamatinein in rhizome and root, and berberine and jatrorrhizine in root at 2 600-2 700 m, and jatrorrhizine in rhizome at 2 300 m. The content of major active compounds in wild C. teeta rhizome and root were significantly higher at 2 600 m and 2 700 m than at 2 100 m and 2 300 m (P<0.05), and the rhizome biomass, root biomass, leaf biomass, total biomass, height, and canopy diameter of wildC. teeta ramet increased first and decreased then from the altitude 2 100 m to 2 700 m. Increasing planting density and enhancing artificial management could improve the biomass of C. teeta and its major active compounds concentrations.

Effects of waterlogging on root respiration intensity and respiratory enzyme activities of sweet cherry.

CHEN Qiang¹;GUO Xiu-wu²;HU Yan-li¹;MAO Zhi-quan^1,2

2008, 19(07):  1462-1466 . 

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Taking Meizao/Dongbeishanyingtao (Prunus serrulata G. Don) and Meizao/Mahaleb (P. mahaleb L.) as test materials, the respiration intensity and respiratory enzyme activities of their growing roots and brown lignified roots were determined under waterlogging. The results showed that under waterlogging, the root respiration intensity of the two kind rootstocks had a decreasing trend, with more decrement for their growing roots. For P. serrulata, the decrement of the respiration intensity of its growing roots and brown lignified roots was 1.47 and 1.36 times as much as that of P. mahaleb, respectively. The pyruvate decarboxylase (PDC) and lactate dehydrogenase (LDH) activities of the two kind roots had a decrease after an initial increase. Alcohol dehydrogenase (ADH) activity in growing roots also had a decrease after an initial increase, but that in brown lignified roots had an increasing trend. The test three enzyme activities changed more in growing roots than in brown lignified roots. The increment of ADH and LDH activities was higher for P. serrulata than for P. mahaleb, while PDC activity was in adverse. The malate dehydrogenase (MDH) activity of the two kind roots decreased, and the decrement was larger in growing roots than in brown lignified roots. P. serrulata had a larger decrement of root MDH activity than P. mahaleb. To the waterlogging stress, growing roots was more sensitive than brown lignified roots, and P. serrulata was more sensitive than P. mahaleb.

Leaf water potential of spring wheat and field pea under different tillage patterns and its relationships with environmental factors.

ZHANG Ming;ZHANG Ren-zhi;CAI Li-qun

2008, 19(07):  1467-1474 . 

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Based on a longterm experiment, the leaf water potential of spring wheat and field pea, its relationships with environmental factors, and the diurnal variations of leaf relative water content and water saturation deficient under different tillage patterns were studied. The results showed that during whole growth period, field pea had an obviously higher leaf water potential than spring wheat, but the two crops had similar diurnal variation trend of their leaf water potential, i.e., the highest in early morning, followed by a descent, and a gradual ascent after the descent. For spring wheat, the maximum leaf water potential appeared at its jointing and heading stages, followed by at booting and flowering stages, and the minimum appeared at filling stage. For field pea, the maximum leaf water potential achieved at squaring stage, followed by at branching and〖HJ*6〗 flowering stages, and the minimum was at podding stage. The leaf relative water content of spring wheat was the highest at heading stage, followed by at jointing and flowering stages, and achieved the minimum at filling stage; while the water saturation deficient was just in adverse. With the growth of field pea, its leaf relative water content decreased, but leaf water saturation deficient increased. The leaf water potential of both spring wheat and field pea had significant correlations with environmental factors, including soil water content, air temperature, solar radiation, relative air humidity, and air water potential. Path analysis showed that the meteorological factor which had the strongest effect on the diurnal variation of spring wheat’s and field pea’s leaf water potential was air water potential and air temperature, respectively. Compared with conventional tillage, the protective tillage patterns no-till, notill plus straw mulching, and conventional tillage plus straw returning increased the leafwater potential and relative water content of test crops, and the effect of no-till plus straw mulching was most significant.

Physiological responses of cotton plant to fertlizer nitrogen at flowering and boll-forming stages under soil drought.

LIU Rui-xian;GUO Wen-qi;CHEN Bing-lin;ZHOU Zhi-guo

2008, 19(07):  1475-1482 . 

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With pot culture, the physiological responses of cotton plant to fertilizer nitrogen at flowering and boll-forming stages were studied under soil drought and after re-watering. The results showed that under soil drought, the net photosynthetic rate (P_n) and transpiration rate (T_r) declined rapidly with decreasing soil relative water content (SRWC). At the early stage of soil drought, owing to the declining degree of T_r was greater than that of P_n, the WUE had an increasing trend; but after then, the WUE decreased with declining SRWC and P_n. Soil drought altered the diurnal patters of P_n and T_r, i.e., decreased continuously from 8:00 to 16:00, while in CK, their peak values appeared at 10:00-11:00 and 12:00, respectively. The diurnal patterns of WUE in drought treatment and CK were the same, i.e., decreased first and increased then, with the bottom appeared at 12:00. Under soil drought, the P_n and T_r decreased with increasing fertilizer nitrogen level, while WUE was in adverse. After re-watering, the diurnal patterns of P_n, T_r and WUE were similar to CK, but their values were smaller than CK, especially under nitrogen application. It was suggested that under soil drought, nitrogen fertilization could be helpful to the increase of water use efficiency, but decreased the photosynthesis of cotton plant at its flowering and boll-forming stages.

Effects of N fertilization levels on ammonia volatilization from rice shoot at later growth stages.

CHEN Gang;XU Yang-chun;SHEN Qi-rong

2008, 19(07):  1483-1488 . 

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With simulated pot culture in greenhouse, the ammonia volatilization from rice shoot and its affecting factors after flowering was studied under different N fertilization levels. The results showed that the daily and total amount of volatilized ammonia increased with increasing N application rate, with a certain variance among different N levels observed. At flowering and maturing stages, the ammonia volatilization from rice shoot (y) had significant negative correlations with functional leaf GS activity (x₁) and positive correlations with functional leaf apoplastic NH₄+ concentration (x₂), with y=-0.37846x₁ +0.41821x₂+0.04925 (R²=0.9471, n=16), and negative correlations with N harvest index (x₁) and physiological N use efficiency (x₂), following y=-0.02117x₁+0.75186 (R²=0.842, n=8) and y=-1.10386x₂+35.52676 (R²=0.8489, n=8), respectively. It was suggested that the increasing ammonia volatilization from rice shoot under high N fertilization level was correlated with the decrease of N use efficiency by rice.

Evolvement characteristics and coupling relationship of soil organic carbon and total nitrogen in subtropical paddy field ecosystem under different fertilization practices.

LIU Chang^1,2;TANG Guo-yong^1,2;TONG Cheng-li¹;XIA Hai-ao³;JIANG Ping³;LIN Yun-hua⁴

2008, 19(07):  1489-1493 . 

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Soil samples were collected from longterm monitoring plots of paddy field ecosystem in Hunan Province to study the evolvement characteristics and coupling relationship of soil organic carbon and total nitrogen under different fertilization practices. The results showed that in 1986-2003, the contents of soil organic carbon and total nitrogen had a slight decrease under no fertilization (CK), basically remained stable under chemical fertilization (NPK), and increased under the combined application of organic manure and chemical fertilizers. Compared with those in CK, the contents of soil organic carbon and total nitrogen in treatments NPK, low application rate organic manure, and high application rate organic manure were increased by 13% and 18%, 54% and 45%, and 89% and 67%, respectively. There was a significant positive correlation (P<0.01) between soil organic carbon and total nitrogen. The soil C/N was around 10, with the majority ranged from 8.5 to 12.9. It was suggested that a combined application of organic manure and chemical fertilizers on paddy field could increase the sequestration and accumulation of soil carbon and nitrogen to a certain extent, and there existed a better coupling relationship between soil organic carbon and total nitrogen in paddy field ecosystem.

Effects of long-term fertilization on paddy soil organic carbon mineralization.

CHEN Tao¹;HAO Xiao-hui¹;DU Li-jun²;LIN Shan¹;FENG Ming-lei¹;HU Rong-gui¹;GAO Jing-yun¹

2008, 19(07):  1494-1500 . 

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An incubation test was conducted with the paddy soil samples collected from three national longterm experiment stations in Hunan Province to study the characteristics of organic carbon mineralization under different fertilization treatments and its relationships with organic carbon fractions, i.e., total organic carbon (TOC), microbial biomass carbon (MBC), and watersoluble organic carbon (WSOC). The results showed that in all fertilization treatments, the cumulative-amounts of CO₂ and CH₄ ranged from 448.64 to 1 516.77 μg·g^-1 and from 15.60 to 33.34 μg·g^-1, respectively. In the 58 days of incubation, the mineralized carbon accounted for 3.59%-557% of TOC. The CO₂ production rate was higher in the early phase of incubation, decreased rapidly then, and tended to stable afterwards; while the CH₄ production rate had a slow increase first and declined rapidly then. A combined application of chemical fertilizers and manure or straw increased the cumulative amounts of CO₂ and CH₄ significantly. In all fertilization treatments, the cumulative mineralized C had significant correlations with TOC, MBC and WSOC, but less correlation with its percentage in TOC.

Effects of organic manure on the profile distribution of soil nitrate-N in a peach orchard.

WANG Yan-ping¹;GAO Ji-xi²;LIU Shang-hua³;DU Xiang-ge¹

2008, 19(07):  1501-1505 . 

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In 2004 and 2005, a field experiment was conducted in a peach orchard in Pinggu District of Beijing to study the effects of organic manure on the profile distribution of nitrateN in soil. Four treatments were installed, i.e., applying 6.75×10⁴ kg·hm^-2 of organic manure both in 2004 and in 2005 (T₁), no fertilization in 2004 but applying 13.5×10⁴ kg·hm^-2 of organic manure in 2005 (T₂), no fertilization in 2004 but applying 6.75×10⁴ kg·hm^-2 of organic manure in 2005 (CK), and no fertilization both in 2004 and in 2005 (CK). In 2006, soil samples at the depth of 0-120 cm were collected from the treatments and analyzed. The results showed that soil nitrate-N had a relatively uniform distribution in the profile in CK, accumulated more at the depth of 0-60 cm and decreased gradually at 60-120 cm in T₁ and T₃, and increased with increasing depth, with the peak at the depth of 100-120 cm in T₂. The soil nitrate-N content below 60 cm in T₂ was the highest among all the treatments, indicating that applying excessive amount of organic manure could induce nitrate-N leaching. The profile distribution of soil nitrate-N had significant correlations with the total amount of applied organic manure, the amount of organic manure applied in the nearest year, and the distance of sampling sites from peach tree. A correlation model of organic manure treatments and soil nitrate-N distribution was established.

Characters of infiltration and preferential flow of black soil in Northeast China under different tillage patterns.

LI Wen-feng^1,2;ZHANG Xiao-ping¹;LIANG Ai-zhen^1,2;SHEN Yan^1,2;SHI Xiu-huan^1,2;LUO Jin-ming^1,2;YANG Xue-ming³

2008, 19(07):  1506-1510 . 

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By using dye tracer and double-ring infiltrometer techniques, the characters of infiltration and preferential flow of black soil under no-tillage (NT) and fall moldboard plow (MP) were compared after six years continuous management. The results showed that the infiltration rate was higher under NT than under MP. When the infiltration reached steady, the infiltration rate and accumulative infiltration capacity under NT were 1.35 and 1.44 times as high as those under MP, respectively. The penetration depth of methylene blue reached a depth of 43 cm in NT soil, being 16 cm deeper than that in MP soil. Comparing with MP soil, NT soil had better development of pore structure and more biological pores, and presented better preferential flow character, which were of importance for water infiltration and soil and water conservation.

Infiltration characteristics of soil water on loess slope land under intermittent and repetitive rainfall conditions.

LI Yi^1,2;SHAO Ming-an²

2008, 19(07):  1511-1516 . 

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Based on the experiments of controlled intermittent and repetitive rainfall on slope land, the infiltration and distribution characteristics of soil water on loess slope land were studied. The results showed that under the condition of intermittent rainfall, the cumulative runoff during two rainfall events increased linearly with time, and the wetting front also increased with time. In the interval of the two rainfall events, the wetting front increased slowly, and the infiltration rate was smaller on steeper slope than on flat surface. During the second rainfall event, there was an obvious decreasing trend of infiltration rate with time. The cumulative infiltration on 15° slope land was larger than that of 25° slope land, being 178 mm and 88 mm, respectively. Under the condition of repetitive rainfall, the initial infiltration rate during each rainfall event was relatively large, and during the first rainfall, both the infiltration rate and the cumulative infiltration at various stages were larger than those during the other three rainfall events. However, after the first rainfall, there were no obvious differences in the infiltration rate among the next three rainfall events. The more the rainfall event, the deeper the wetting front advanced.

Spatial variability of soil total K and available N in Shenyang urban area.

ZHANG Hong-wei;WEI Zhong-yi;WANG Qiu-bing

2008, 19(07):  1517-1521 . 

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Geostatistics combined with geographical information system（GIS）was applied to analyze the spatial variability of soil total K and available N in urban area of Shenyang City. The results showed that the theoretical semivariogram models of soil total K was best described by an exponential model, while soil available N was best fitted by a Gaussian model. The ratios of nugget to sill of soil total K and available N were 10.65% and 17.96%, respectively, indicating that there existed significant spatial correlations between soil total K and available N, and the spatial variability was mainly caused by structural factors. The spatial distributions of soil total K and available N in urban area of Shenyang were analyzed by kriging interpolation, and it was found that the content of soil total K had no definite spatial distribution pattern, while the content of soil available N was higher in the around and lower in the middle of the city.

Application of catastrophe progression method in assessing urban ecological security of Xiamen City, China.

WEI Ting¹;ZHU Xiao-dong¹;LI Yang-fan¹;SUN Xiang¹;CHEN Bin²;WANG Jin-keng²

2008, 19(07):  1522-1528 . 

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Aiming at the potential catastrophic characteristics of coastal city under rapid urbanization, and based on the P-S-R (pressure-state-response) framework and catastrophe progression method (CPM), this paper developed a catastrophe model for the assessment of urban ecosecurity, and assessed the ecological security status (ESS) of Xiamen City from 1996 to 2006. The results showed that from 1996 to 1998, the ESS had an improving trend, revealing that the rapid urbanization in this period had less effect on the regional ecosecurity. From 1998 to 2001, owing to the largescale and profound ecological disturbances from sea reclamation and rapid population increase that far overstepped the ecological remediation ability of Xiamen City’s ecosystem itself, the ESS declined rapidly. From 2001 to 2006, the ESS improved again, because of the significant strategic transformation of Xiamen City from its original island-based configuration to a new eco-city with larger bay area. In 2006, the security of Xiamen ecosystem pressure remained at grade Ⅲ, suggesting that this city still had a potential risk of ecological security. According to our research results, CPM revealed the catastrophic effects of large development projects on ecosystems when a single index was at extreme, and offset the drawbacks of existing methods in this regard. CPM also had less subjectivity in weight evaluation and less uncertainty in estimating the standard of security, and consequently, could evaluate the status and development trend of urban eco-security exactly.

Simulation and prediction of urban and rural settlement growth and land use change in Yingkou City.

XI Feng-ming^1,2;HE Hong-shi¹;HU Yuan-man¹;WU Xiao-qing³;BAO Li⁴;TIAN Ying^1,2;WANG Jin-nian⁵;MA Wen-jun⁶

2008, 19(07):  1529-1536 . 

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Based on the 1988, 1992, 1997, 2000, and 2004 Landsat TM remote sensing data of Yingkou City, Liaoning Province, the urban and rural settlement growth and land use change in the city from 2005 to 2030 were simulated and predicted by using the SLEUTH urban growth and land use change model with six scenarios (current trend scenario, no protection scenario, moderate protection scenario, managed growth scenario, ecologically sustainable growth scenario, and regional and urban comprehensive planning scenario). The results showed that in the city, the increased area of urban and rural settlement growth from 1988 to 2004 was 14.93 km², and the areas of water area, orchard, mine, and agricultural land changed greatly from 1997 to 2004. From 2005 to 2030, based on ecologically sustainable growth scenario, the urban and rural settlement growth would have a slow increase, and agricultural land and forestland would be better protected; under no protection scenario, the urban and rural settlement growth would have a rapid increase, and large area of agricultural land would be lost; under current trend scenario, the agricultural land loss would be similar to that under no protective scenario, but the loss pattern could be different; under moderate protection scenario and managed growth scenario, the agricultural land would have a smaller loss; while under regional and urban comprehensive planning scenario, the urban and rural settlement growth would be mainly distributed in urban development area and urban fringe. The SLEUTH model with different scenarios could simulate how the different land management policies affect urban and rural settlement growth and land use change, which would be instructive to the coordination of Chinese urban and rural settlement development and the socialist new rural reconstruction.

Impacts of rail transit in Shanghai on its urban land use change.

LI Cheng¹;LI Jun-xiang^1,2;LI Rong¹;XU Ming-ce¹;QIN Hai¹

2008, 19(07):  1537-1543 . 

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By using the land use data interpreted with 1∶50 000 colorinfrared aerial photos of Shanghai collected in 1989 and 2005, and based on Geographic Information System (GIS) techniques, the impacts of urban rail transit (URT) development in Shanghai on its urban land use change was quantitatively analyzed, and a preliminary prediction of the land use change from 2010 to 2025 was made with Markov probability models. The results showed that the URT accelerated the land use change, particularly from an agricultural dominated natural landscape in 1989 to a highvalue manmade urban landscape primarily composed of residence and public facilities. URT increased the land use rate in the study area. From 1989 to 2005, public facility land, green space, agriculture land, land for other uses (primarily used for construction), and water area changed greatly, with the greatest change rate of the land for other uses and the lowest one of water area. From 2010 to 2025, the areas and proportions of agriculture land and water area would keep on decreasing, while those of man-made landscapes including esidence and public facilities would increase continuously. From the viewpoints of increasing land use rate and its gain, the present land use structure along Shanghai URT should be further regulated to improve the intensive and sustainable use of land resources.

Simulation model for the development stages of processing tomato based on physiological development time.

WANG Ji-chuan^1,2;MA Fu-yu¹;FENG Sheng-li¹;CHEN Yuan-liang³;HE-Wei⁴;PANG Sheng-qun¹

2008, 19(07):  1544-1550 . 

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After the comprehensive consideration of the effects of temperature and light on the development physiology of processing tomato, the intrinsic development factor (IDF) was introduced, and, through the analysis of the dynamic relationships between the development stages of different type processing tomato and related environmental factors, the simulation model for the development stages of processing tomato was constructed, based on the concept of physiological development time (PDTv). Different years’ experimental data about ecological zones, varieties, and planting modes were used to validate the model. The simulated results about the number of days from sowing to seedling emergence, flowering, fruitsetting, maturing, and ending accorded well with the observed ones, the root mean squared error (RMSE) being 1.09, 2.03, 2.05, 2.77 and 2.53 days, respectively, and the prediction accuracy of this model was significantly higher than that of the growth degree day (GDD)based model, with the corresponding RMSE being 1.90, 6.63, 6.33, 9.36 and 6.84 days, respectively.

Simulation on spatiotemporal dynamics of main prey populations of Panthera tigrisin East Wanda Mountains.

GUO Qing-xi;GAO Mei-xiang;WANG Hua-ru

2008, 19(07):  1551-1558 . 

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By using landscape-level animal population simulator (LAPS), the spatiotemporal dynamics of the main prey populations of Panthera tigris from 1990 to 2009 in East Wanda Mountains were simulated, based on the different scenarios of accidental mortality and carrying capacity that could represent the influence of direct and indirect human disturbance. The effects of the accidental mortality and carrying capacity on the population dynamics were studied, and the spatiotemporal distribution of animal blocks was exhibited explicitly in the study area, with the individual density in different patches compared. The results showed that compared with carrying capacity, accidental mortality had more effects on prey populations, and the population density was significantly higher in shrubs than in broadleaved forests. The conclusions made in this study could provide scientific basis for the conservation and management of P. tigris’s preys in East Wanda Mountains, while the quantitative validation of the conclusions still needs further investigation.

Effects of nitrogen application rate on rhizosphere microbial community in wheat-faba bean intercropping system.

DONG Yan¹;TANG Li¹;ZHENG Yi¹;ZHU You-yong¹;ZHANG Fu-suo²

2008, 19(07):  1559-1566 . 

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With field plot experiment, this paper studied the effects of different nitrogen application rate (0, 90, 180 and 270 kg·hm^-2) on the rhizosphere microbial community and its diversity in wheatfaba bean intercropping ecosystem. The results indicated that the amount of rhizosphere microbes fluctuated with crop growth stages, being the highest at the flowering stage of test crops. Comparing with monocropping, intercropping significantly increased the totalamount of microbes and the numbers of bacteria, fungi and actinomyces in the rhizosphere of both wheat and faba bean, but decreased the microbial diversity in the rhizosphere of faba bean at its flowering and maturing stages. Under no nitrogen and low nitrogen application rate, a larger difference was observed in the amount of rhizosphere microbes between intercropping and monocropping. The promotion effect of intercropping in increasing the amount of rhizosphere microbes was more apparent at tillering and flowering stages, but declined significantly at maturing stage. With increasing nitrogen application rate, the amount of microbes in wheat rhizosphere increased first and decreased then, with the peak appeared at 180 kg N·hm^-2, and the effect was more obvious on monocropped wheat than on intercropped one. Nitrogen application rate had no significant effects on the numbers of bacteria, fungi and actinomyces and the microbial diversity in faba bean rhizosphere, but decreased the total amount of microbes in the rhizosphere of intercropped faba bean. Rational nitrogen application could regulate rhizosphere microbial community effectively, and there was an obvious correlation between aboveground plant diversity and belowground microbial community.

Characteristics of bacterial community in an arable mollisol under longterm phosphorus fertilization.

BAI Zhen^1,2;ZHANG Ming³;ZHANG Xu-dong¹;ZHU Ping⁴;PENG Chang⁴

2008, 19(07):  1567-1573 . 

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Soil samples were taken from the Gongzhuling national long-term experimental station in Jilin Province of Northeast China to study their basic physical and chemical properties and the characteristics of bacterial community under different fertilization systems, i.e., CK, P, N-P, N-P-K, manure-P, manure-N-P, and manure-N-P-K. The results showed that applying manure increased the contents of soil organic matter (OM), total nitrogen (TN), available phosphorus (AP), alkalihydrolysable nitrogen (AN) and available potassium (AK) significantly, while applying chemical fertilizers had no significant effects on the contents of soil OM and AN. Comparing with CK, the total bacterial phospholipid fatty acids, G⁺ bacterial phospholipid fatty acids, and G^- bacterial phospholipid fatty acids in treatments manure-N-P and manure-N-P-K increased by 34% and 62%, 58% and 74%, and 64% and 69%, respectively. Applying chemical fertilizers, especially P, decreased the bacterial phospholipid fatty acids. Except G⁺ bacterial phospholipid fatty acids whose content was significantly higher in treatment manure-P than in treatment N-P-K, the bacterial phospholipid fatty acids had no significant difference between treatments N-P, N-P-K and manure-P. There existed significant correlations between various groups of bacterial phospholipid fatty acids and soil OM, AN, AP, AK, and NO3^--N .

Relationship between soil fungistasis and bacterial community structure.

WU Min-na^1,2;ZHANG Hui-wen¹;LI Xin-yu¹;ZHANG Yan^1,2;SU Zhen-cheng¹;ZHANG Cheng-gang¹

2008, 19(07):  1574-1578 . 

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As a natural attribute of clean and healthy soil, fungistasis is an important indicator of soil quality, and has positive ecological significance to the inhibition of plant disease eruption caused by soilborne fungal pathogens. In this study, soil samples (0-15 cm) were collected from the abandoned land at Shenyang Experimental Station of Ecology, Chinese Academy of Sciences, to which pesticides and fertilizers have never been applied for nearly 10 years. A series of soil samples with gradient fungistasis was obtained by heating (CK, 100 ℃, 110 ℃, and 121 ℃ for 4 min, respectively), and bacterial community structure was analyzed by Polymerase Chain Reaction coupled with Denaturing Gradient Gel Electrophoresis method (PCR-GGGE). The results showed that there was a significant correlation between soil fungistasis and bacterial community composition. Treatment CK showed the strongest capacity to control the growth of target soil-borne pathogenic fungi. The further the bacterial community structure of treated soil deviated from that of CK, the lower the soil fungistasis was. Sequencing and the following phylogenetic analysis of special bands in DGGE indicated that Sphingomonas asaccharolytica, Nitrospira sp., Hyphomicrobiaceae sp.,Bacillus megaterium, and Micrococcus sp. could be involved in soil fungistasis.

Degradation effect of two pure cultured ectomycorrhizal fungi on diesel.

LI Xiao;HUANG Yi;WEI Zhi-cheng

2008, 19(07):  1579-1584 . 

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The study on the growth characteristics of two ectomycorrhizal fungi Gomphidius viscidus and Laccaria bicolor under 10 g·L^-1 of diesel and their degradation effect on the diesel showed that both of the ectomycorrhizal fungi could utilize diesel as their only carbon source. After 14day culture, the degradation effect was 39.90% for Laccaria bicolor and 31.32% for Gomphidius viscidus, and the degraded hydrocarbons were mainly 16C-22C alkenes. The capability of the ectomycorrhizal fungi to degrade diesel varied with the components of culture medium. When glucose was used as the second carbon source, the biodegradation capability of the fungi was inhibited, though the fungal biomass was 2-5 times as much as that without glucose addition. High concentration of inorganic nitrogen could promote the degradation effect to a certain extent, but not greatly.

Microbial degradation of acetochlor in mollisol and the effects of acetochlor on the characteristics of soil phospholipid fatty acids.

FENG Hui-min^1,2;HE Hong-bo¹;BAI Zhen¹;WU Ye-ye¹;GUO Bai-dong¹;ZHANG Ming³;ZHANG Xu-dong¹

2008, 19(07):  1585-1590 . 

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An incubation test was conducted with mollisol applied with recommended amount of acetochlor under the conditions of sterilization, microbial inhibitor addition, and nonsterilization. During incubation, the residual amount of acetochlor and the dynamics of soil phospholipid fatty acids (PLFAs) were determined to study the relative contribution of soil microbes on the degradation of applied acetochlor, and the effects of acetochlor on the soil microbial community structure. The results showed that acetochlor was easy to be degraded by soil microbes, and bacteria contributed more than fungi. After applying acetochlor, the contents of various PLFAs changed evidently, and the soil microbial biomass indicated by C14∶0, C16∶0 and C18∶0 was decreased. The bacterial PLFAs decreased significantly at the beginning of the incubation, but had less difference with CK (no acetochlor application) later, suggesting that bacterial activity was restored along with the degradation of acetochlor. The content of fungal PLFAs in the soil samples applied with acetochlor was lower than that of CK, implying that the inhibition of the herbicide to fungi was chronic and irreversible.

Effects of leachate irrigation and cover soil type on N₂O emission from municipal solid waste landfill.

HE Pin-jing;CHEN Miao;ZHANG Hou-hu;SHAO Li-ming

2008, 19(07):  1591-1596 . 

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By the method of static chamber, the seasonal and diurnal variations of N₂O fluxes in two fullscale municipal solid waste (MSW) landfills covered with sandy and clay soils were measured to study the effects of leachate irrigation and cover soil type on the landfill N₂O emission. The results showed that the N₂O flux in the MSW landfill covered with sandy soil was （242±576） μg N₂ON·m^-2·h^-1 in summer, being 3.2 times (P>0.05) as high as that in spring ［(74.4±314） μg N₂O N·m^-2·h^-1］, while the N₂O flux in the MSW landfill covered with clay soil was （591±767） μg N₂ON·m^-2·h^-1 in summer, being 2.2 times (P<0.05) as high as that in spring ［(269±335） μg N₂ON·m^-2·h^-1］. Leachate irrigation promoted the N₂O emission from the soil cover of the landfill covered with sandy soil, and the N₂O flux in the landfill was 1 time higher than that of the control (P>0.05). Under leachate irrigation, the average N₂O flux in spring and summer in the landfill covered with sand soil was （211±460） μg N₂ON·m^-2·h^-1, being only 1/2 of that ［(430±605） μg N₂ON·m^-2·h^-1］ in the landfill covered with clay soil without leachate irrigation (P>0.05). Therefore, no matter leachate irrigation was conducted or not, the N₂O emission from MSW landfill could be inimized by covering with infertile sandy soil.

Preliminary survey on aquatic vegetations in Baiyangdian Lake.

LI Feng^1,2;XIE Yong-hong¹;YANG Gang¹; REN Bo¹;HOU Zhi-yong¹;QIN Xian-yan^1,2

2008, 19(07):  1597-1603 . 

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A field survey was conducted on the species composition, community type, distribution pattern, and biomass of aquatic vegetations in the Baiyangdian Lake of Hebei Province. A total of 39 species were observed, including 16 emergent species, 14 submerged species, 6 floatingleaved species, and 3 floating species, belonging to 21 families and 32 genera. Compared with those about 15 years ago, 9 species were disappeared, community types were decreased from 16 to 13, and some predominant communities with large distribution area, such as Hydrilla verticillata and Najas major, were not found in the present survey. Meanwhile, the distribution pattern of aquatic vegetations was greatly changed. The biomass of aquatic vegetations decreased dramatically, compared to the survey in 1980. Human cultivation, random discharge of pollutants, and tremendous change of water level could be the main reasons for the degradation of aquatic vegetations and the great change of their distribution pattern in the Lake.

Effects of fishing on the marine ecosystem of Beibu Gulf.

CHEN Zuo-zhi^1,2,3;QIU Yong-song¹;JIA Xiao-ping¹;ZHONG Zhi-hui¹

2008, 19(07):  1604-1610 . 

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By using Ecopath with Ecosim 5.1 software, the Ecosim model of Beibu Gulf marine ecosystem  in 1959-1960 was constructed, which included about 20 functional groups such as fishery, marine mammals, seabirds, sharks, pelagic fishes, demersal fishes, and benthic crustaceans, etc. Through the comparison with the investigation data in 1997-1999, the effects of fishing on the structure and function of Beibu Gulf marine ecosystem were analyzed. The results indicated that with the increasing fishing pressure in past forty years, the ecosystem structure and function shifted drastically, with the biomass of long-lived, high trophic level and piscivorous fishes declined while short-lived and small fishes and benthic invertebrates dominated gradually. The biomass of piscivorous species in 1999 was only 6% of that in 1960, while cephalopods increased 2.7 times or more. The trophic level of the catch declined from 3.2 in 1960 to 2.98 in 1999, which fitted the rule of “fishing down the food web” and suggested that the present exploitation patterns were unsustainable. Based on the data of the 1990s, the changes of the ecosystem under decreasing fishing pressure were predicted. This study validated the feasibility of Ecosim model in predicting the effects of fishing pressure on marine ecosystem.

Application effect, affecting factors, and evaluation of nitrification inhibitor: A review.

SUN Zhi-mei^1,2;WU Zhi-jie¹;CHEN Li-jun¹;MA Xing-zhu^1,3

2008, 19(07):  1611-1618 . 

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The agronomic, environmental, and ecological significances of applying nitrification inhibitor (NI) have been demonstrated by many researches, but the efficiency of NI application was affected by many factors. In this paper, the effects of NI on soil N transformation, nitrate leaching and greenhouse gases emission, fertilizer N use efficiency, yield and quality of agricultural products, and availability of soil nutrients besides N were reviewed, and the factors affecting the efficiency of NI application as well as the evaluation criteria of NI were summarized.

Regulation of photosynthesis by light quality and its mechanism in plants.

ZHENG Jie;HU Mei-jun;GUO Yan-ping

2008, 19(07):  1619-1624 . 

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Photosynthesis is the basis of plant growth and development. The regulations of photosynthesis by light quality include regulations of stomatal movement, leaf growth, chloroplast structure, photosynthetic pigment, D1 protein and its gene and photosynthetic carbon assimilation by visible light, and effect of ultraviolet light on photosystem Ⅱ in plant. Blue light and red light can promote the opening of stomata, while the green light can close stomata. Blue light can improve the development of chloroplast, complex light of red, blue and green lights can expand leaf area, and red light can increase the accumulation of photosynthesis production. Effects of different light quality differ in various plants, organs and tissues. Blue light and far red light can promote the accumulation of psbA gene transcription. Most higher plants and green algae have highest photosynthesis rate in orange and red lights, secondly in blue-violet light, and minimum in green light. Ultraviolet light can decline the electron transfer activity of photosystem Ⅱ. Moreover, questions regarding the effect of light quality on photosynthesis and some topics for future study were also discussed in this paper.

Biological and ecological bases of using insect as a bio-indicator to asses forest health.

WANG Yi-ping;WU Hong;XU Hua-chao

2008, 19(07):  1625-1630 . 

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Insect is an important component of forest biodiversity, which is closely related with plant in the main community of forest ecosystem. Intimidation of forest pest and variation of insect diversity is of importance for assessing forest ecosystem health. Insect diversity can be used for rapidly assessing forest ecosystem health. For example, indicator insects have been used to evaluate toxicity levels, abundance of species, levels of biodiversity, target insect status, and endemism levels for forest ecosystem. With a focus on the important interference factors influencing forest environmental health, this paper clarified the biological and ecological basis for insects to be used as a bio-indicator to monitor and assess forest health. We also discussed the fluctuation of insect populations, especially that of the population of the rare species under the influence of habitat fragmentation, and the density and distribution of the insect population under the influence of air pollution, drought, increased CO₂ concentration. Meanwhile, the existing problems to use insects as a bioindicator to monitor and assess forest environmental health were analyzed.

Effects of alternative partial rootzone irrigation on peach growth, productivity, and water use efficiency.

SONG Lei¹;YUE Yu-ling¹;DI Fang-kun²;WEI Qin-ping³;GAO Zhao-quan³;ZHANG Ji-xiang¹

2008, 19(07):  1631-1636 . 

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Taking 12-year-old peach (Prunus persica L. Batsch cv. Ruiguang 5) as test material, this paper studied the effects of alternative partial rootzone irrigation (APRI) on its growth, productivity, and water use efficiency under semiarid climate condition. The results showed that in APRI treatments, the soil water content in the wet side of peach tree decreased with increasing soil depth, while that in the dry side was in adverse, with the maximal tifference appeared in 0-25 cm soil layer. In the treatments of APRI with an interval of 2 and 4 weeks, the leaf water potential at pre-dawn was lower than that in the control (sufficient irrigation), but with the time prolonged, this potential in all treatments tended to decrease, and had no significant difference in the afternoon. The peach yield in APRI treatments was 10% lower than that in the control, but the irrigation amount was reduced by 50%, and the water use efficiency was increased by 75%. APRI significantly limited the shoot growth of peach tree, but had no obvious effect on the fruit diameter.