Table of Content

20 January 2010, Volume 21 Issue 01

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Articles

Effects of atmospheric calibration on remote sensing estimation of Moso bamboo forest biomass.

FAN Wei-Liang, DU Hua-Jiang, ZHOU Guo-??*, XU Xiao-Jun, CUI Rui-Juan, DONG De-Jin

2010, 21(01):  1-8. 

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Landsat Thematic Mapper (TM) image was used to estimate Moso bamboo forest biomass, and six atmospheric calibration methods (FLAASH model, 6S model, and DOS1-4 models) were adopted to analysis the effects of atmospheric calibration on the remote sensing estimation of Moso bamboo forest biomass. All the six calibration methods could effectively reduce the atmospheric impacts on TM spectral responses. The relationships between NDVI and Moso bamboo forest biomass under the calibration by the six calibration methods were improved. Great differences were observed in the relationships of Moso bamboo forest biomass with NDVI, II , and MI when using the same calibration methods, suggesting that atmospheric calibration should be made for studying the biophysical significance of vegetation indices. The Landsat TM data corrected with DOS3 model had the highest correlation coefficient with Moso bamboo forest biomass, but there were no significant differences in the correlation coefficients after corrected with the six calibration methods, which indicated that atmospheric calibration might be not required if a single TM image was used for biomass estimation with multiple linear regression model.

Natural regeneration characteristics of Sorbus pohuashanensis in forest region of eastern Northeast China.

HU Jian-Wei, CHEN Hai-long, ZHANG Xiu-Liang, ZHANG Peng

2010, 21(01):  9-15. 

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Sorbus pohuashanensis is an important non timber tree species in Northeast China. Aimed to study the natural regeneration characteristics of this
 tree species and related affecting factors, representative S. pohuashanensis forests in the  forest region of eastern Northeast China were investigated by line sampling method. In this forest region, S. pohuashanensis was regenerated by seed propagation, stump sprouting, and root sprouting. In intact or poor habitat natural forests, the proportions of the S. pohuashanensis seedlings established by each of the three regeneration methods occupied roughly a third, with no significant difference (P＞0.05) among them; while in secondary forests, the frequency of stump sprouts (16.5%) was lower than that in natural forests. Even so, the combination of stump sprouting and root sprouting could likely maintain a stable local population. Root sprouting could make the seedlings spread more than 50 cm away from the stump. The transfer rate from diameter class II (1.0-2.9 cm) to diameter class Ⅲ (3.0-4.9 cm) was 25.6% in secondary forests, 45.3% in poor habitat natural forests, and 15.9% in intact natural forests, suggesting that the lower transfer rate was the key limiting factor for S. pohuashanensis natural regeneration.

Biomass- and energy allocation in Eucalyptus urophylla×Eucalyptus tereticornis plantations at different stand ages.

ZHOU Qun-Yang, CHEN Shao-Xiong, HAN Fei-Yang, CHEN Wen-Beng, TUN Zhi-Hua

2010, 21(01):  16-22. 

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An investigation was made on the biomass- and energy allocation in 1-4-year-old  Eucalyptus urophylla×Eucalyptus tereticornis plantations at Beipo Forest Farm of Suixi County in Guangdong Province. Stand age had significant effects on the retained biomass of the plantations (P＜0.01). The biomass was in the range of 10.61－147.28 t·hm^-2. Both the total biomass and the biomass of above- and belowground components increased with increasing stand age. The proportions of leaf , branch and bark biomass to total biomass decreased with year, while that of stem biomass was in reverse. The biomass allocation of the components in 1- and 2- year-old plantations decreased in  order of stem＞branch＞bark＞root＞leaf, and that in 3-  and 4-year-old plantations  was in  order of stem＞root＞branch＞bark＞leaf. The mean ash content (AC) of the five components at different stand ages ranged from 0.47% to 5.91%, being the highest in bark and the lowest in stem. The mean gross caloric value (GCV) and ash free caloric value (AFCV) of different components ranged from 17.33 to 20.60 kJ·g^-1 and from 18.42 to 21.59 kJ·g^-1 respectively. Of all the components, leaf had the highest GVC and AFCV, while bark had the lowest ones. Stand age had significant effects on the GVC   of branch, stem,and bark, and on the AFCV of leaf, stem, and bark (P＜0.05), but the effects on the GVC of leaf and root, the AFCV of branch and root, and the GVC and AFCV of individual trees were not significant (P＞0.05). The retained energy of 1-4-year-old plantations ranged from 199.98 to 2837.20 GJ·hm^-2, with significant differences among the stand ages (P＜0.01). The retained energy of various components and plantations increased with stand age, and the energy allocation of various components had the same trend as biomass allocation.

Effects of weeding methods on weed community and its diversity in a citrus orchard in southwest Zhejiang.

TAO He-Jin, JIN Zong-Lai, YANG Wei-Bin, DIAO Jian-Hua, ZHANG Fan

2010, 21(01):  23-28. 

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By using the research methods of ecological community, the effects of different weed management strategies including chemical weeding, manual weeding, and their combination on the weed community and its diversity in a citrus chard of main orange producing region in Quzhou City, Zhejiang Province were studied from June 2005 to May 2008. In control plots, there were 75 species and 25 families of weeds; after chemical weeding, manual weeding, and their combination, there were 46 species and 17 families, 59 species and 20 families, and 51 species and 18 families of weeds, respectively. The Margalef’s species richness index, Shannon’s diversity index, and Shannon’s evenness index were the lowest after chemical weeding, but the highest after manual weeding, suggesting that chemical weeding had the greatest effects on the weed diversity in the citrus orchard. It was suggested that to sufficiently control the weeds while to maintain the weed diversity in the orchard weeds in southwest Zhejiang, the combination of chemical and manual weeding would be the best management strategy.

Effects of low temperature- and weak light stress and its recovery on the photosynthesis and chlorophyll fluorescence parameters of cut flower chrysanthemum.

LIANG Fang, ZHENG Cheng-Chu, SUN Xian-Zhi, WANG Wen-Chi-

2010, 21(01):  29-35. 

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The cut flower chrysanthemum ‘Jinba’ was respectively treated with lower temperature and weaker light (16 ℃/ 12 ℃, PFD 100  μmol·m^-2·s^-1) and critical low temperature and weak light (12 ℃/8 ℃, PFD 60 μmol·m^-2·s^-1 ) for 11 days, and then transferred to normal condition (22 ℃/18 ℃, PFD 450 μmol·m^-2·s^-1) for 11 days, aimed to study the low temperature and weak light stress and its recovery on the photosynthesis and chlorophyll fluorescence of chrysanthemum leaves. Under the stress of lower temperature and weaker light, the net photosynthetic rate (P_n) and stomatal limitation (L_s) of chrysanthemum leaves decreased while the intercellular CO₂ concentration (C_i) increased, the maximal photochemical efficiency of
PSⅡ(F_v/F_m) in dark and the initial fluorescence (F_o) had no obvious change, but the maximal photochemical efficiency of PSⅡ (F_v'/F_m′) in light increased after an initial decrease. Contrarily, under the stress of critical low temperature and weak light, the F_o increased, and the F_v/F_m and F_v'/F_m' decreased significantly. The quantum yield of PSⅡelectron transport (Φ_PSⅡ), photochemical quenching (q_P),and apparent photosynthetic electron transfer rate (ETR) of chrysanthemum leaves decreased with increasing stress and time, and recovered quickly after the release of lower temperature and weaker light stress but more slowly after the release of critical low temperature and weak light stress. At the same time,the photochemistry react rate (Prate) decreased, but the hot dissipation of antenna (Drate) and the energy dissipation of PSⅡ (Ex) increased under the stress conditions. Drate was the main pathway of superfluous light allocation.

Stomatal response of spring wheat and related affecting factors under different irrigation treatments.

CHENG Xue-Feng, ZHANG Feng-Yun, CHAI Shou-Xi

2010, 21(01):  36-40. 

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Taking three spring wheat cultivars as test materials, a field experiment was conducted to study the effects of different irrigation treatments on the stomatal conductance of the cultivars during their growth period, with the relationships between the stomatal conductance and the environmental factors analyzed. On the basis of winter irrigation with 1800  m³·hm^-2of water, three irrigation treatments, i.e., irrigating three times (T₁), two times (T₂
), and once (T₃) during spring wheat growth period, were installed, with 1050 m³·hm^-2of irrigation water each time. All irrigation treatments had greater effects on the stomatal conductance, which was decreased with the decreasing times of irrigation, and varied with the cultivars. From jointing stage to florescence, the stomatal conductance in all treatments had the same variation trend, i.e., decreased after an initial increase, and reached the peak at heading stage. After florescence, difference occurred among the treatments. In treatment T₁, the stomatal conductance of all test cultivars increased after an initial decrease; in treatment T₂, the variation patterns of stomatal conductance differed with cultivars; while in treatment T₃, the conductance of all cultivars decreased all along. Among the environmental factors, relative atmospheric humidity had the greatest effects on the stomatal conductance, and their correlation coefficient in treatments T₂ and T₃ reached significant (0.82^*)and very significant (0.92^**). respectively. The stomatal regulation mechanism of spring wheat adapting to water deficit in Hexi corridor was of feedback manner.

Morphological and physiological differences of wheat genotypes at seedling stage under water stress.

TIAN Meng-Yu, LI Dan-Dan, DAI Ting-Bei, JIANG Dong, JING Ai, CAO Wei-Xing

2010, 21(01):  41-47. 

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Taking thirty six wheat cultivars bred in different era and ecological regions as test materials, their seedlings growth under water stress was investigated, and their drought resistance was evaluated by gray correlation grade analysis. Significant difference was observed in the drought resistance among the cultivars. The weighted drought resistance index ranged from 0.6580 to 0.2434. Among the test seventeen morphological and physiological traits, shoot dry mass had the greatest correlation degree (0.9473) with drought resistance, while SPAD had the smallest one (0.5356). The test cultivars were clustered into three groups, among which, eight cultivars belonged to strong drought resistance group, twenty three cultivars belonged to medium drought resistance group, and five cultivars belonged to drought-sensitive group. The shoot dry mass, root dry mass, plant dry mass, plant height, root nitrogen accumulation, leaf area, and tiller number per plant differed significantly among the three groups, which could be used for evaluating the drought resistance of wheat cultivars at seedling stage.

Effects of drought stress on the grain yield and root physiological traits of maize varieties with different drought tolerance.

JI Wei, ZHANG Ji-Wang, WANG Kong-Jun, LIU Feng, DONG Shu-Ting

2010, 21(01):  48-52. 

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A pot experiment was conducted to study the effects of simulated moderate drought in whole growth period on the grain yield and root physiological traits of drought-tolerant maize variety JK 628 and drought-sensitive maize variety ND-95. Compared with the control, the grain yield of JK-628 and ND-95 under the stress of moderate drought was decreased by 33.7% and 62.3%, respectively. Under drought stress, the root biomass of the two varieties decreased, with the maximum value appeared ahead. The root/shoot ratio of JK-628 increased at early growth stage but decreased at late growth stage, while that of ND-95 increased all along. ND-95 had a larger decrement of root activity than JK-628. The root SOD activity in drought stress plants was higher in prophase but lower in anaphase, compared with that in the control, and the time of SOD activity begun to lower was later for JK-628 than for ND-95. The root MDA content in drought-stress plants was increased, and the increment was much higher for ND-95 than for JK-628. In addition, the root soluble protein content in drought-stress plants was decreased, and ND-95 had a larger decrement than JK-628. In a word, under drought stress, the root activity, SOD activity, and soluble protein content of JK-628 were higher than those of ND-95, which could slow down the root aging process and prolong the root functional period, possibly being one of the important factors of getting high yield of drought-tolerant maize under drought stress.

Effects of nitrogen application rate on cotton leaf antioxidant enzyme activities and endogenous hormone contents under short-term waterlogging at flowering and boll-forming stage.

GUO Wen-Qi, CHEN Bing-Lin, LIU Rui-Xian, ZHOU Chi-Guo

2010, 21(01):  53-60. 

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A pot experiment was conducted to study the effects of applying 0, 240, and 480 kg N·hm^-2 on the cotton leaf antioxidant enzyme activities and endogenous hormone contents under eight days waterlogging at flowering and boll-forming stage. Under this short-term waterlogging, the leaf soluble protein content and SOD and CAT activities decreased while the MDA content and POD activity increased, and in the meantime, the leaf ABA content increased while the ZR, GA, and IAA contents as well as the ZR/ABA, IAA/ABA, and GA/ABA ratios decreased, compared with those under normal watering. Treatment 240 kg N·hm^-2 had the lowest contents of leaf MDA and ABA, but the highest contents of leaf ZR, GA, and IAA, highest ratios of ZR/ABA, GA/ABA, and IAA/ABA, and highest net photosynthetic rate. At the 15th day after terminating waterlogging, no significant differences in the leaf antioxidant enzyme activities, MDA content, and endogenous hormone contents were observed between the short-term waterlogged and well-watered cotton. N application promoted the cotton leaf antioxidant enzyme activities, decreased the MDA and ABA contents, and increased the ZR, GA, and IAA contents as well as the ZR/ABA, IAA/ABA, and GA/ABA ratios, with the highest cotton biomass and yield in treatment 240 kg N·hm^-2.

Inheritance of parthenocarpy in monoecious cucumber (Cucumis sativus L.) under different eco-environments.

YAN Li-Yang, LOU Li-Na, FENG Zhi-Gong, LOU Qun-Feng, LI Xiao-Li, CHEN Jin-Feng

2010, 21(01):  61-66. 

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By using the mixed major gene plus polygene inheritance model of quantitative traits, a joint analysis of four generations obtained after cross between two monoecious inbred lines was made to study the inheritance of parthenocarpy in monoecious cucumber in Jiangning (Nanjing) and Changli(Hebei). The interactions between genotype and environment were detected, and the inheritance of parthenocarpy in the monoecious cucumber was fitted in E-1-1 model and controlled by two additive-dominant-epistatic major genes and additive dominant-polygene under different eco environments. The F₁ tendency and genetic parameters of the parthenocarpy were different, and the major gene heritability of F₂ ranged from 42.1% to 97.5%, which was mainly due to the differences in sunlight intensity and air temperature during fruit-setting period at the two locations. It was suggested that the parents should be highly parthenocarpic in breeding program, and the characterization of parthenocarpy should be conducted under different
eco-environments.

Effects of water supply tension on photosynthetic characteristics and root activity of greenhouse cucumber.

LI Shao, XUE Xu-Zhang, GUO Wen-Shan, LI Xia, CHEN Fei

2010, 21(01):  67-73. 

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To study the effects of soil water content on the photosynthesis, fluorescence parameters, and root growth of greenhouse cucumber (Cucumis sativus L.), a pot experiment was conducted, using a negative pressure water supplying and controlling device to control soil moisture regime. Seven levels of water supply tension (WST), i.e., 1, 3, 5, 7, 9, 11, and 13 kPa, were designed. The WST was inversely proportional to soil water content, and the gravimetric soil water content was maintained in the range of 14.23%-42.32%. With increasing WST, the leaf net photosynthetic rate (P_n) in different growth periods showed a parabolic trend, being higher when the WST was 7-11 kPa at initial flowering stage, and was 3-5 kPa at fruiting stage. The reason for the decreased P_n at 9-13 kPa WST was stomatal limitation. Under 1-5 kPa WST, the actual photochemical efficiency (Φ _PSⅡ ) had a high value，and the possibility of photo inhibition was small. Both the leaf transpiration rate and the chlorophyll content were positively correlated with leaf  P_n in different growth periods. Root growth and activity also had a parabolic trend with increasing WST. The maximum root dry mass and root activity happened at 7 kPa and 5 kPa WST, respectively. Our results indicated that a WST of 3-7 kPa was more profitable for the leaf photosynthesis and root growth of greenhouse cucumber.

Effects of substrate-aeration cultivation pattern on tomato growth.

DIAO Xu, LI Tian-Lai, SUN Zhou-ping

2010, 21(01):  74-78. 

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Aeroponics can increase the fruit yield of tomato plant, but its cost is very high. In this paper, tomato seedlings were planted with three cultures, i.e., whole perlite culture (CK), perlite-aeration culture (T₁), and aeroponics (T₂), and a comparative study was made on the seedlings growth. Compared with CK, T₁ improved the gas environment in root zone significantly, with the CO₂ and O₂ concentrations in root zone being 0.2 and 1.17 times higher, and increased the plant height and stem diameter after 60 days of transplanting by 5.1% and 8.4%, respectively. The plant net photosynthetic rate of T₁ was significantly higher than that of CK, with the maximum value after transplanting 45 days increased by 13%. T₁ also increased the root activity and ion absorbing ability significantly, with the root activity after transplanting 45 days being 1.23 times of CK, and the root K, Ca, and Mg contents after transplanting 60 days increased by 31%, 37%, and 27%, respectively. The fruit yield of T₁ was 1.16 times of CK. No significant differences in these indices were observed between T₁and T₂, and less difference in the fruit soluble sugar and organic acid contents as well as the sugar acid ratio was found among CK, T₁, and T₂. It was suggested that perliteaeration cultivation pattern was an easy and feasible way to markedly improve the fruit yield of tomato plant.

Effects of alternate partial root-zone subsurface drip irrigation on potato yield and water use efficiency.

HUANG Zhong-Dong, JI Hua-Bin, FAN Xiang-Yang, HU Chao, SHU Dong-Hai, LI Beng, JIAO Dong-Mei

2010, 21(01):  79-83. 

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Field experiment was conducted to investigate the effects of alternate partial root-zone subsurface drip irrigation (APRSDI) on the physiological responses, yield, and water use efficiency of potato. Compared with conventional drip irrigation (CDI), APRSDI had less negative effects on the potato leaf photosynthesis rate (P_n), but decreased the transpiration rate and stomatal conductance significantly. The slightly higher P_n under CDI was at the expense of consuming more water. No significant difference was observed in the potato yield under APRSDI and CDI, but APRSDI saved the irrigation amount by 25.8% and increased the irrigation water use efficiency and total water use efficiency by 27.5% and 15.3%, respectively, suggesting that APRSDI would be a feasible water-saving irrigation technique for the planting of potato.

Content and evolution characteristics of organic carbon associated with particle-size fractions of grey desert soil under long-term fertilization.

LIU Hua, TONG Xiao-Gang, MA Xin-Wang, WANG Xi-He, ZHANG Wen-Ju, HU Yong-Mei, XU Meng-Gang

2010, 21(01):  84-90. 

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Physical fractionation technique was used to analyze the content, distribution, and temporal evolution of organic carbon associated with particle-size fractions of grey desert soil under long term (1990-2007) fertilization. Compared with no fertilization, a combined application of manure and chemical fertilizers increased the organic carbon associated with particle-size fractions significantly, with the highest increment (0.34 g·kg^-1·a^-1) in sand. Fallowing also increased the organic carbon associated with clay and silt significantly. Straw return to cropland only maintained the organic carbon content in different particle size fractions, while long-term application of chemical fertilizers was not beneficial to the organic carbon increase in particle-size fractions. Coarse silt and coarse clay had the highest distribution rates of organic carbon (27.9% and 27.1%, respectively), being the important fractions in sequestrating organic carbon. When manure was applied with chemical fertilizers, the organic carbon in sand was significantly increased by 119.4%, while that in fine silt and coarse clay was significantly decreased by 40.3% and 37.9%, respectively, which resulted in  the increase in the ratio of particulate organic carbon content (W_POC) to mineral associated organic carbon content (W_MOC), and improved soil carbon property. Long term application of manure combined with chemical fertilizers was the best mode to increase the organic carbon content in particle size fractions and improve the fertility of grey desert soil.

Effects of tillage conversion on carbon sequestration capability of farmland soil doubled cropped with wheat and corn.

HAN Bin, KONG Fan-Lei, ZHANG Hai-Lin, CHEN Fu

2010, 21(01):  91-98. 

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By the methods of field experiment, laboratory analysis, and in situ investigation, this paper studied the effects of different tillage conversion on the carbon sequestration capability of farmland soil doubled cropped with wheat and corn. Compared with conventional tillage (CTA), conservation tillage practices benefited the accumulation of soil organic carbon, among which, notillage plus straw returning (NTS) increased the organic carbon accumulation in 0-5 cm soil layer by 18.0%, rotary tillage plus straw returning (RTS) increased this accumulation in 0-5 and 5-10 cm soil layers by 17.6% and 25;0%, respectively, and conventional tillage plus straw returning (CTS) increased the organic carbon in 10-30 cm soil layer by 31.8%. After the conversion from CTA to NTS, the carbon emission from farm operations decreased by 54.3 kg·hm^-2·a^-1; while the conversion from CTA to CTS and RTS resulted in an increase of this emission by 46.9 kg·hm^-2·a^-1 and 34.4 kg·hm^-2·a^-1, respectively. Considering of the accumulation of soil organic carbon and the carbon emission from farm operations, it could be concluded that the conversion from CTA to conservation tillage changed this farmland soil from carbon source to carbon sink, and the RTS among the three conservation tillage modes resulted in the highest soil carbon sequestration (1011.1 kg·hm^-2·a^-1).

Straw return to rice paddy: Soil carbon sequestration and increased methane emission.

DAI Fei, WANG Xiao-Ke, HAN Bing, OU Yang-Zhi-Yun, ZHENG Hua

2010, 21(01):  99-108. 

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Based on the long-term datasets of soil organic matter content and the observation data of rice paddies’ methane (CH₄) emission collected from the
agricultural experiment stations across the country, the rice paddies in China were divided into single cropping and double cropping regions. The soil carbon sequestration potential of straw return in three types of rice paddies in the tworegions, i.e., single cropping rice paddies, upland/paddy alternated rice paddies, and double cropping rice paddies, was evaluated, based on the datasets of soil oranic matter content; and the total CH₄ emission from  rice paddies without straw return was estimated, with reference to the experimental data of  paddies CH₄ emission and by the method of mean emission coefficient. The total CH₄ emission from our paddies after straw return and the global warming potential of the increased CH₄ emission were also estimated by using the related methods and parameters given by IPCC. It was estimated that the full popuarization of straw return to China’s rice paddies would sequester 10.48 Tg C·a^-1of C, and the contribution to the global warming mitigation was 38.43 Tg CO₂-eqv·a^-1.In the meanwhile, the CH₄  emission from our rice paddies would be increased from 5.796 Tg·a^-1 to 9.114 Tg·a^-1, and the increased 3.318 Tg·a^-1 of CH₄emission would lead to a global warming potential of82.95 Tg CO₂-eqv·a^-1, which was 2.158 times of the mitigation from carbon sequestration in rice paddies. Therefore, the increased CH₄ emission due to straw return should be regarded as an important greenhouse gas leakage, since it could greatly offset the mitigation benefits of soil carbon sequestration in China’s rice paddies.

Near infrared spectroscopy in determining organic carbon and total nitrogen in black soil of Northeast China.

SHEN Yan, ZHANG Xiao-ping, LIANG Ai-Zhen, SHI Xiu-Huan,FAN Ru-Qin,YANG Xue-ming

2010, 21(01):  109-114. 

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In this study, near infrared reflectance spectroscopy (NIRS) was used to determine the organic carbon (OC), total nitrogen (TN), and C/N ratio in black soil of Northeast China. Based on the 3699-12000 cm^-1 NIRS of 136 black soil samples collected in 2004-2005, and by  using. partial least square (PLS), the related quantitative models were established. Leave one out cross validation showed that the OC and TN were well predicted, with the values of coefficient of determination (R²) being 0.92 and 0.91, RPD (the ratio of standard deviation of validation set to root mean square error of cross validation) being 3.45 and 3.36, and correlation coefficient (r) being 0.94 and 0.93 respectively, suggesting that NIRS had the potential to predict the OC and TN in black soil of Northeastern China. However, the C/N ratio was poorly predicted, with R²=0.61, RPD=1.61, and r=0.74, indicating that NIRS could not give reasonable prediction for the C/N ratio in black soil.

Development and evaluation of fertilizers cemented and coated with organic-inorganic materials.

XIAO Jiang, WANG Jia-Chen, ZUO Jiang, ZHANG Lin, LIU Bao-Cun, DIAO Tong-Ke, JU Guo-Yuan, XU Qiu-Mng

2010, 21(01):  115-120. 

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Four kinds of organic-inorganic cementing and coating materials were prepared by a coating method using water as the solvent, and the corresponding cemented and coated fertilizers (B2, PS, F2, and F2F) were produced by disc pelletizer. The tests on the properties of these fertilizers showed that the granulation rate, compression strength, and film-forming rate were B2>PS>F2>F2F. Soil column leaching experiment showed that the curve of accumulated nitrogen dissolving rate was the gentlest for B2. In 48 days, the accumulated nitrogen-dissolving rate was in the order of B2, 54.65%<PS, 56.16%<F2, 59.47%, <F2F, 63.12%.Field experiment showed that compared with the same application amount of NPK, all the test fertilizers had better effects on corn yield, among which, B2 was the best, with the corn yield and fertilizer use efficiency increased by 19.72% and 20.30%, respectively. The yield increasing effect of other test fertilizers was in the order of PS>F2>F2F.

Simulation model of barley leaf area index.

LIU Tie-Mei, WANG Yan, JU Wei, SUN Dong-Fa, SHANG Liang, CAO Wei-Xing

2010, 21(01):  121-128. 

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To simulate leaf area index (LAI) accurately is the key for the prediction of crop growth and yield in a crop growth model. Based on the analysis of the dynamic changes in the LAI of high yielding barley cultivars in Wuhan and Yangzhou, a simulation model of barley LAI was established, in which, the LAI was the function of expansion coefficient of LAI for cultivar genetic property, climatic factors such as daily air temperature difference, sunshine hours, and accumulation of photosynthetic available radiation after sowing (∑PAR), and limitation indices of water and nutrients. It was indicated that the maximum LAI and optimal LAI at the stages of booting and heading were not the same conception, but differed significantly. The model was tested by the field experiments with different barley cultivars under different sowing dates and nitrogen application rates in Yangzhou, Nanjing, and Kunming. The results showed that this model gave thegood predictions of LAI at different development stages, with the RMSE values ranged in 0.742 and 2.865, and averaged 1.348. The simulated and observed LAI values were significantly positively correlated, and the correlation coefficient from y=x regression analysis was between 0.511 and 0.954.

Dynamic simulation of photosynthate allocation in maize organs based on functional equilibrium hypothesis.

BENG Xiao-Yan, ZHOU An-Qing, SUN Jing-Song, HU Zhen-Zhu

2010, 21(01):  129-135. 

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By using the 2004-2008 observation data of maize biomass and related environmental factors from the Jinzhou Agricultural Ecosystem Research Station of Shenyang Institute of Atmospheric Environment under China Meteorological Administration (CMA), the Friedlingstein model was validated and tested at station site and daily time scales. A model of  soil available nutrient coefficient for maize field  was developed, based on fertilization, soil temperature, and soil available water; and a daily time scale maize photosynthate allocation model was built, according to the functional  equilibrium hypothesis. Comparing with Friedlingstein model, the daily time scale maize photosynthate allocation model could give more accurate simulation of photosynthate allocation in maize root, stem, and leaf, and provide technical support for accurate simulation of daily net primary productivity of maize agro-ecosystem.

Prediction of high temperature harm to rice in Jiangsu Province based on sea surface temperature.

BO Ao-Da, GAO Peng, LIU Mei, WANG Chun-Jue

2010, 21(01):  136-144. 

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Based on the measurements of rice growth and the ordinary meteorological observations from eight main agro-meteorological stations in Jiangsu Province in 1986-2007, this paper analyzed the characteristics of generation circulation corresponding to the abnormal strong and southern subtropica
l high pressure in 2003 (the year with a typically high temperature), the relationships between the abnormalities of subtropical high pressure and previous sea surface temperature, and the physiological responses of rice to the abnormal high temperature during its crucial development stages. In the meantime, a field correlation analysis was made on the relationships between the harm index of high temperature in the northern (Huaibei), middle (Jianghuai), and southern (Sunan)areas of Jiangsu and the sea surface temperature (SST) of Western Pacific. The results showed that the harm index of high temperature in the three areas was highly correlated with the SST of Nino area, northern area, and warm pool area of Western Pacific, respectively, but the significance and temporal evolution of the correlations varied among the areas. The transformation of SST was conducted tooptimize its correlation with the harm index of high temperature, and an increased reliability of SST acting as a predictor of high temperature harm was obtained. The simulation results of the established models in predicting high temperature harm to rice in Huaibei, Jianghuai and Sunan areas of Jiangsu Province were significant at 0.01 level.

Effects of atmospheric thermally stratified condition on sensible heat within forest canopy.

DIAO Yi-Wei, WANG An-Zhi, GUAN De-Xin, JIN Chang-Jie, FEI Tie-Fan

2010, 21(01):  145-151. 

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By using Eulerian second-order closure model, this paper studied the source-sink distribution and flux characteristics of sensible heat within forest canopy under atmospheric thermally stratified condition. In the daytime, a notable feature for the atmospheric stratification of forest canopy was the unstable stratification above the canopy and the stable stratification under the canopy. The changes of temperature profile indicated there was a ‘hot spot’ at about 2/3 of canopy height. The counter-gradient fluxes within the canopy were discoered by modeling the heat flux under weak stable atmospheric condition. Simulations of the diurnal variation of sensible heat flux were consistent with the measurements (R²=0.9035, P<0.01). Adding buoyancy in the sensible heat balance equation could increase the simulation accuracy of inversion model, and improve the simulation capability for heat flux balance.

Estimation of sparse vegetation coverage in arid region based on hyperspectral mixed pixel decomposition.

LI Xiao-Song, GAO Zhi-Hai, LI Ceng, BAI Li-Na, WANG Beng-Yu

2010, 21(01):  152-158. 

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Based on Hyperion hyperspectral image data, the image-derived shifting sand, false Gobi spectra, and field-measured sparse vegetation spectra were taken as endmembers, and the sparse vegetation coverage (<40%) in Minqin oasisdesert transitional zone of Gansu Province was estimated by using fully constrained linear spectral mixture model (LSMM) and non constrained LSMM, respectively. The results showed that the sparse vegetation fraction based on fully constrained LSMM described the actual sparse vegetation distribution. The differences between sparse vegetation fraction and field-measured vegetation coverage were less than 5% for all samples, and the RMSE was 3.0681. However, the sparse vegetation fraction based on non-constrained LSMM was lower than the field-measured vegetation coverage obviously, and the correlation between them was poor, with a low R² of 0.5855. Compared with McGwire’s corresponding research, the sparse vegetation coverage estimation in this study was more accurate and reliable, having expansive prospect for application in the future.

Applicability of different models in simulating the relationships between forest fire occurrence and weather factors in Daxing’an Mountains.

GUO Fu-Chao, HU Hai-Qing, MA Zhi-Hai, ZHANG Yang

2010, 21(01):  159-164. 

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The Poisson’s and Zero Inflated Poisson (ZIP) models that meet the data structure of forest fire occurrence were used to explore the relationships between the forest fire occurrence and climate factors in Daxing’an Mountains in 1980-2005. Compared with the ordinary least squares (OLS) model which often produced poor fitting results (R²=0.215), the Poisson’s and ZIP models operated better, and had better prediction ability on the forest fire occurrence. The AIC and Vuong tests further indicated that ZIP model produced better fitting results, and thus, had better prediction ability than Poisson model.

Soil microbial properties under different vegetation types in Loess hilly region.

ZHANG Yan-Yan, QU Lai-Xie, CHEN Li-Ding, WEI Wei

2010, 21(01):  165-173. 

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By using fumigation-extract (FE) method and Biolog Ecoplate, this paper investigated the microbial biomass and diversity in 0-20 cm soil layer under five vegetation types, including artificial woodland, shrubland, cropland, abandoned farmland, and natural grassland, in Dingxi of Gansu Province. In the meanwhile, the relationships between soil microbes and soil nutrients were studied by path analysis, and the five typical vegetation types were evaluated from the aspect of soil microbes. Relative to cropland, “grain for green” project played a key role in improving soil microbial resources. Microbial biomass carbon was the highest in ridge grassland, abandoned farmland, and pine woodland, followed by in Caragana korshinskii land, Medicago sativa land, restored land, and roadside land, and in wheat field and potato field. Microbial biomass nitrogen was the highest in ridge land, abandoned farmland, Pinus tabulaeformis woodland, Caragana korshinskii land, and Medicago sativa land, followed by in restored land and roadside land, and in wheat field and potato field. Caragana korshinskii land and Medicago sativa land, due to the existence of N-fixing rhizobium, had the highest ratio of soil microbial biomass nitrogen to soil total nitrogen. Owing to the continual biomass loss and rare feedback, cropland had the lowest quantity and activity of soil microbes. Through planting trees, shrubs and grasses or through fallowing, soil microbial biomass and activity were recovered, and the effect was increased with time. In 20-year old Caragana korshinskii land, the quantity and activity of soil microbeswere similar to those in 50-year old Pinus tabulaeformis woodland, and the microbial community catabolic activity and soil nutrient use efficiency were higher. Considering the features of soil microbes under test vegetation types, Caragana korshinskii would be a good choice for local vegetation restoration.

Species composition and ecological distribution of macrofungi in Huangpushan Natural Reserve of Anhui Province.

CHAI Xin-Xi

2010, 21(01):  174-180. 

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In order to understand and utilize the macrofungal resources in Huangpushan Natural Reserve of Anhui Province, their species composition and ecological distribution were investigated, and a comprehensive evaluation was made. A total of 87 macrofungal species were recorded, belonging to 46 genera, 22 familes, 6 orders and 4 classes. They were widely distributed in broadleaf forest, coniferous forest, mixed broadleaf and coniferous forest, bamboo forest, and wasteland. According to their economic values, there were 42 edible species, 31 medicinal species, and 6 poisonous species; based on their ecological habitats, they were categorized into humicolous (44 species), lignicolous (30), ectomycorrhizal (19), and entomogenous species (2). The macro-fungi in the Reserve had great prospects of applying in food, medicine, and forestation.

Soil faunal diversity under typical alpine vegetations in West Sichuan.

HUANG Xu, WEN Wei-Quan, ZHANG Jian, YANG Mo-Qi, LIU Xiang, YAN Bang-Guo, HUANG Yu-Mei

2010, 21(01):  181-190. 

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In order to understand the variations of soil faunal diversity under different natural alpine vegetations in West Sichuan, an investigation was made on the soil faunal communities under alpine coniferous forest, shrub, and meadow from August 2008 to June 2009. A total of 48343 individuals were collected, belonging to 7 phyla, 16 classes, 31 orders and 117 families. There was a great difference in the dominant groups of soil macro-fauna, and a significant difference (P＜0.05) in the number of soil faunal groups under different vegetations. Both the individual density and the group number of soil fauna decreased obviously with increasing soil depth, and were significantly higher (P＜0.01) in moss layer than in litter layer in coniferous forest. Significant difference (P＜0.01) was also observed in the density-group index among the three vegeations. The maximum biomass of soil macro fauna was found in June. Jacard indices indicated that disturbed meadow had the lowest similarity of soil faunal community with the other  vegetations. It was suggested that vegetation type had significant effects on the community structure of soil fauna, while aspect, altitude, and disturbance also had definite effects.

Biological control efficiency of Amblyseius cucumeris (Oudemans) on Panonychus ulmi (Koch).

ZHANG Hui-Yuan, MA Meng, DONG Tie, LIU Xiao-Yong, ZHANG Kun, WANG Fa-Lin

2010, 21(01):  191-196. 

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Based on the life-table parameters and the release effects of Amblyseius cucumeris (Oudemans) under laboratory and field conditions, the control efficiency of  A. cucumeris (Oudemans) on Panonychus ulmi (Koch) was evaluated. When feeding on P. ulmi, A. cucumeris could complete its development period and lay eggs with one generation time of 9.54 d at (25±1) ℃. The egg-laying period (24.85 d) and lifespan (38.52 d) of female A. cucumeris were longer than their preys (15.93 d and 34.79 d, respectively), but the averageamount of eggs laid by female A. cucumeris was 36.70, being 43.9% less than that of  P. ulmi. The net reproductive rate (R₀) and intrinsic rate of natural increase (r_m) of P. ulmi were 103.9% and 13.2% higher than those of  A. cucumeris, respectively. No matter what the good-harm ratios was 1∶30 or 1∶150, the control efficiency of  A. cucumeris after its 20-day release under laboratory condition could be over 95%, and the efficiency after 60-dayrelease under field condition could be  91.73%, being 23.77% higher than that when sprayed with pesticide, suggesting that A. cucumeris was a good biological agent to control the population growth of P. ulmi. When the P. ulmi population density was less than 2 per leaf, releasing A. cucumeris in the orchard could effectively control the population increase of P. ulmi.

Effects of azadirachtin on rice plant volatiles induced by Nilaparvata lugens.

LU Hai-Yan, LIU Fang, ZHU Shu-De, ZHANG Qing

2010, 21(01):  197-202. 

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With the method of solid phase microextraction (SPME), a total of twenty-five volatiles were collected from rice  plants  induced by Nilaparvata lugens, and  after applying azadirachtin  fourteen of them were qualitatively identified by gas chromatography coupled by mass spectrometry (GC-MS), mainly of nine kinds of sesquiterpenes. Comparing with healthy rice plants, the plants attacked by N. lugens had more kinds of volatiles, including limonene, linalool, methyl salicylate, unknown 6, unknown 7, zingiberene, nerolidol, and hexadecane. Applying azadirachtin did not result in the production of new kind volatiles, but affected the relative concentrations of the volatiles induced by N. lugens. The proportions of limonene, linalool, methyl salicylate, unknown 6, zingiberene, and hexadecane changed obviously with the concentration of applied azadirachtin, while those of methyl salicylate, unknown 6, unknown 7, zingiberene, and nerolidol changed significantly with the days after azadirachtin application. Azadirachtin concentration, rice variety, and N. lugens density had significant interactions on the relative concentrations of all test N. lugens-induced volatiles.

Resistance mechanisms of Spodoptera exigua (Hübner) to fenvalerate and alpha-cypermethrin.

LAN Yi-Quan, ZHAO Shi-Xi

2010, 21(01):  203-208. 

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By using synergist bioassay and biochemical analysis, this paper approached the resistance mechanisms of Spodoptera exigua (Hübner) to fenvalerate and alpha-cypermethrin. The synergistic ratios of piperonyl butoxide (PBO), o,o-diethyl-o-phenyl-thiophosphate (SV₁), triphenyl phosphate (TPP), and diethyl maleate (DEM) between fenvalerate-resistant strain (Fen-R) and susceptible strain were 10.2, 7.8, 12.5, and 1.1, and those between alpha-cypermethrin resistant strain (Cyp-R) and susceptible strain were 21.6, 15.5, 8.6, and 1.2, respectively. Significant synergisms of PBO, SV₁, and TPP to fenvalerateand alpha-cypermethrin wereobserved, implying that multifunctional oxidase and carboxylesterase were involved in the resistance to fenvalerate and alpha-cypermethrin. The carboxylesterase activities in the fourth instar larvae of Cyp-Rand Fen-R strains were 1.9 and 2.2 folds of the corresponding susceptible strains, respectively, but no differences were found in the glutathione-S-transferase activities between the resistant and susceptible strains, which indicated that carboxylesterase played an important role in the resistance of S. exigua to fenvalerate and alpha-cypermethrin, while glutathione-S-transferase contributed little to the resistance. There were no significant differences in the Na-K-ATPase activities between the resistant and susceptible strains, but the inhibition of fenvalerate and alpha-cypermethrin on Na-K-ATPase was higher in the susceptible strains than in the resistant strains, indicating the decreased sensitivity of Na-K-ATPase in resistant strains.

Distribution and composition of organochlorine pesticides in surface water body of Chaohu Lake.

2010, 21(01):  209-214. 

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By the method of SPE-GC/ECD, this paper studied the distribution and composition of organochlorine pesticides (OCPs) in the surface water body of Chaohu Lake. At the 13 sampling sites of study area, a total of 16 kinds of OCPs, including HCHs, DDTs, β-Endosulfan, Aldrin, hexachlorobenzene, and Heptachlor, were detected. The total OCPs concentration was 0.54-64.01 ng·L^-1, and the main components were HCHs and DDTs, whose average concentrations were 5.56 ng·L^-1 and 16.57 ng·L^-1, respectively, accounting for about 84.75% of the total. The origins of OCPs in study area were historical residues and the recent discharge of pesticides. The concentrations of all existences accorded with the target values of GB 3838-2002. The concentrations of OCPs in the surface water body of Chaohu Lake were much lower, and the risk was low in general.

Effects of incubation temperature and substrate humidity on embryonic development of Mauremys mutica.

2010, 21(01):  215-220. 

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Yellow pond turtle (Mauremys mutica) eggs were incubated in vermiculite under nine combinations of temperature and humidity, i.e., 25 ℃ and -12 kPa, 29 ℃ and -12 kPa, 33 ℃ and -12 kPa, 25 ℃ and -150 kPa, 29 ℃ and -150 kPa, 33 ℃ and -150 kPa, 25 ℃ and -300 kPa, 29 ℃ and -300 kPa, and 33 ℃ and -300 kPa, aimed to study the effects of incubation temperature and its interaction with substrate humidity on the embryonic development of M. mutica. The initial egg mass, incubation temperature, substrate humidity, and the interaction of incubation temperature and substrate humidity had significant effects on the mass increment of egg in the course of hatching. At the same temperature, eggs incubated in wetter substrates (-12 kPa) gained more mass than those incubated in drier substrates (-150 kPa and -300 kPa). Incubation temperature affected hatching period significantly, while substrate humidity and its interaction with temperature did not. Both incubation temperature and substrate humidity affected hatching success and shell crack rate significantly. Abnormal hatchlings were found when incubated at 25 ℃ and 33 ℃, but not at 29 ℃. Incubation temperature had significant effects on the hatchling mass, carapace length and width, plastron length and width, body height, and tail length; while substrate humidity only affected hatchlings plastron length. The interaction of incubation temperature and substrate humidity did not affect the morphology of hatchlings.

Evaluation of sustainable utilization of fishery resources in Guangdong Province.

CHEN Zuo-Zhi, LIN Zhao-Jin, QIU Yong-Song-

2010, 21(01):  221-226. 

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Sustainable utilization of fishery resources is the key for the sustainable development of fisheries, and its evaluation is a critical topic in the management of fisheries. Based on the theories of sustainable utilization, an index system suitable for the evaluation of the sustainable utilization of fishery resources in Guangdong Province was established, and a hierarchy and comprehensive grey evaluation model was adopted to evaluate this sustainable utilization in 1978-2007. In the study period, the utilization level of fishery resources in this province had an overall decrease, being the lowest in 1998, only 37.3% of that in 1978; but in the nearest 10 years, this utilization level had an increasing trend, with that in 2007 being 55.1% of 1978. The results of comprehensive evaluation were consistent with the observed facts, indicating that the model was feasible to evaluate the sustainable utilization of regional fishery resources.

Effects of storage medium and temperature on short-term storage of Acipenser baerii eggs.

ZHANG Chao, YA Shi-Wei, PENG Beng, ZHANG Long-Zhen, TIAN Mei-Beng, WANG Bin, ZHANG Da-Hai, TAO Zhi-Feng

2010, 21(01):  227-231. 

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This paper studied the effects of different storage medium (coelomic fluid, Hepes solution, and modified Ringer’s solution), temperature (4 ℃ and 16℃), and duration (4 h, 8 h, 16 h, and 24 h) on the short-term storage of Siberian sturgeon (Acipenser baerii) eggs. The results showed that storage medium, temperature, and duration all had significant effects on the fertilization rate, hatching success, and malformation of newly hatched larvae (P<0.05). With the increase of storage duration, the fertilization and hatching rates decreased, while the malformation rate of hatched larvae increased. The A. baerii eggs stored at 16 ℃ had higher fertilization, hatching, and malformation rates but shorter holding time than those stored at 4 ℃. The optimal conditions for the short-term storage of A. baerii  eggs were Hepes solution prepared according to the biochemical composition of A. baerii coelomic fluid, 16 ℃, and 4 h, under which, 86.36% fertilization rate, 94.74% hatching rate, and zero malformation would be obtained.

Action mechanisms of plant growth-promoting rhizobacteria (PGPR): A review.

KANG Yi-Jun, CHENG Ji, MEI Li-Juan, HU Jian, PIAO Zhe, YAN Shi-Hua

2010, 21(01):  232-238. 

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Plants during their growth may suffer from many biotic and abiotic stresses, resulting in a decrease of biological production. They may also establish some mechanisms to resist or tolerate the stresses under the stimulation or induction by a variety of factors, among which, plant growth-promoting rhizobacteria (PGPR) is an important one. In this paper, the recently published papers related to this subject were reviewed, and two categories of the action mechanisms of PGPR, namely, induced systemic resistance (ISR) and induced systemic tolerance (IST), were elaborated. The diversity of the action mechanisms of PGPR implied that PGPR could be applied in more agro-ecosystems.

Seed geography: Its concept and basic scientific issues.

XU Shun-Li, WANG Zong-Shuai, ZE Ren-Wang-Mu

2010, 21(01):  239-246. 

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In this paper, a new concept ‘seed geography’ was provided, and its definition, research contents, and scientific issues were put forward. Seed geography is a newly developed interdisciplinary science from plant geography, seed ecology, and phytosociology, which studies the geographic variation patterns of seed biological traits as well as their relationships with environmental factors from macroscopic to microscopic, and the seed formation, development, and change trends. The main research contents would include geography of seed mass, geography of seed chemical components, geography of seed morphology, geography of seed cell biological characteristics, geography of seed physiological characteristics, geography of seed genetic characteristics, and geography of flower and fruit. To explore the scientific issues in seed geography would help us to better
 understand the long-term adaptation and evolution of seed characteristics to natural environments.

Nitrogen loss and its control during livestock manure composting.

HUANG Xiang-Dong, HAN Zhi-Yang, DAN De-Zhi, HUANG Chi, TUN Wei-Xiang, LIU Yu-Hua

2010, 21(01):  247-254. 

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Composting is an effective way to realize livestock manure treatment and recycling. However, the nitrogen loss during manure composting is relatively
serious. Studies on this nitrogen loss and its control could provide theoretic basis and practical reference for efficient nitrogen loss control. This paper described the nitrogen transformation and the main nitrogen loss ways during the composting, and summarized the main factors (including raw material characteristics, environment factors, and technological conditions) affecting the nitrogen loss in the composting. In addition, the research progress in the nitrogen loss control, including adjusting carbon and nitrogen metabolism, changing nitrogen form,adding ammonia adsorbent, and controlling pile aeration and temperature, was reviewed, and the prospects for future research were presented.

Atmospheric dry and wet nitrogen deposition |in typical agricultural areas of North Shaanxi. 

WEI Yang, TONG Yan-An, DUAN Min, JIAO Li, TIAN Gong-Wei, LEI Xiao-Ying, MA Wen-Juan

2010, 21(01):  255-259. 

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To investigate the farmland soil nitrogen input from atmospheric dry and wet deposition, a 1-year observation was conducted in the Yulin and Luochuan areas of North Shaanxi Province from June 2007 to May 2008. The total inorganic nitrogen (TIN) deposition in Yulin and Luochuan was 22.17 and 16.95 kg·hm^-2·a^-1, among which, wet deposition accounted for 95.1% and 90.4%, while dry deposition accounted for 4.9% and 9.6%, respectively, illustrating that the nitrogen deposition in both Yulin and Luochuan was mainly come from wet deposition. In the TIN deposition, the amount of nitrate in Yulin and Luochuan was 12.22 and 9.24 kg·hm^-2·a^-1, accounting for 55.1% and 54.5%, respectively. The amount of wet deposition and the percentage of nitrate in TIN deposition were higher in Yulin than in Luochuan, because of the differences in pollution level, weather condition, and underlying surface characteristics.

Effects of enhanced UV-B radiation on leaf anthraquinones content and cell ultr astructure of Aloe vera L .

WANG Gong-Xing, YANG Tong-Wen, LI Jing-Yuan

2010, 21(01):  260-264. 

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By using transmission electron microscopy and high performance liquid chromatography, this paper studied the effects of enhanced UV-B radiation on the leaf anthraquinones content and cell ultrastructure of Aloe vera L. After treated with enhanced UV-B radiation 6 hours per day for 20 days, the total anthraquinone content, barbaloin content, and aloe-emondin content in A. vera leaves increased by 31.8%，11.3%, and 22.0%, respectively, chloroplast envelope membrane was slightly damaged, but the structure of other organelles had no significant change. It was suggested that UV-B radiation could promote the accumulation of anthraquinone in A. vera leaves, but had less effects on the leaf cell ultrastructure.