The present study was planned to analyze the yield gap of wheat and its production constraints in order to explore the approaches for narrowing the yield gap of wheat in different wheat-rice rotation regions of Anhui ...The present study was planned to analyze the yield gap of wheat and its production constraints in order to explore the approaches for narrowing the yield gap of wheat in different wheat-rice rotation regions of Anhui Province. The production status and limiting factors of wheat in three rice-wheat rotation regions which are named Region Ⅰ,Region Ⅱ and Region Ⅲ were surveyed by using participatory rural appraisal method. The personnel,who were engaged in wheat production in rice-wheat rotation regions of Anhui Province,mainly ageing from 41 to 60,accounted for 79% of the total personnel in the regions. There were significant differences in yield of wheat which was planted after rice in Anhui. The yield was ranging from 8 907. 00 to 2 700. 00 kg/ha from north to south with an average of 4 978. 5 kg/ha,and the rank of overall average yields at province level was Region Ⅰ( 5 685. 60 kg/ha) > Region Ⅱ( 5 600. 10 kg/ha) > Region Ⅲ( 3 048. 60 kg/ha). The average yield gap of wheat in wheat-rice rotation regions at province level was up to 2 637. 00 kg/ha,and the extreme yield gaps per hectare in the same region were 2 778. 00 kg( Region Ⅰ),2 502. 00 kg( Region Ⅱ) and 1 575. 00 kg( Region Ⅲ) respectively. The objective constraints were Fusarium head blight and pre-harvest sprouting;the subjective constraints were variety selection and layout,poor sowing quality and low seedling quality;social constraints were high cost,low market price and poor efficiency;and ecological constraints were poor soil texture,soil infertility and poor water-and-fertilizer retention. The yield gap of wheat in rice-wheat rotation regions can be effectively reduced by improving yield potential of low-and-medium-yielding fields. Selecting appropriate wheat varieties and layout,constructing disease forecast system,improving agricultural machinery and social service organizations of plant protection,and strengthening scientific training as well as technological training of new agricultural operators and agricultural machinery technicians are the core means to narrowing the yield gap of wheat in rice-wheat rotation regions at province scale.展开更多
Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season. Rapeseed cake and ...Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season. Rapeseed cake and wheat straw were incorporated into the soil at a rate of 2.25 t hm(-2) when the rice crop was transplanted in June 2001. Compared with the control, the incorporation of rapeseed cake enhanced the emissions of CO2, CH4, and N2O in the rice-growing season by 12.3%, 252.3%, and 17.5%, respectively, while no further effect was held on the emissions of CO2 and N2O in the following wheat-growing season. The incorporation of wheat straw enhanced the emissions of CO2 and CH4 by 7.1% and 249.6%, respectively, but reduced the N2O emission by 18.8% in the rice-growing season. Significant reductions of 17.8% for the CO2 and of 12.9% for the N2O emission were observed in the following wheat-growing season. A positive correlation existed between the emissions of N2O and CO2 (R-2 = 0.445, n = 73,p < 0.001) from the rice-growing season when N2O was emitted. A trade-off relationship between the emissions of CH4 and N2O was found in the rice-growing season. The CH4 emission was significantly correlated with the CO2 emission for the period from rice transplantation to field drainage, but not for the entire rice-growing season. In addition, air temperature was found to regulate the CO2 emissions from the non-waterlogged period over the entire rice-wheat rotation season and the N2O emissions from the nonwaterlogged period of the rice-growing season, which can be quantitatively described by an exponential function. The temperature coefficient (Q(10)) was then evaluated to be 2.3+/-0.2 for the CO2 emission and 3.9+/-0.4 for the N2O emission, respectively.展开更多
Rational application of nitrogen (N) fertilizers is an important measure to raise N fertilizer recovery rate and reduce N loss.A two-year field experiment of rice-wheat rotation was employed to study the effects of ...Rational application of nitrogen (N) fertilizers is an important measure to raise N fertilizer recovery rate and reduce N loss.A two-year field experiment of rice-wheat rotation was employed to study the effects of N fertilization modes including a N fertilizer reduction and an organic manure replacement on crop yield,nutrient uptake,soil enzyme activity,and number of microbes as well as diversity of microbes.The result showed that 20% reduction of traditional N fertilizer dose of local farmers did not significantly change crop yield,N uptake,soil enzyme activity,and the number of microbes (bacteria,actinomycetes,and fungi).On the basis of 20% reduction of N fertilizer,50% replacement of N fertilizer by organic manure increased the activity of sucrose,protease,urease,and phosphatase by 46-62,27-89,33-46,and 35-74%,respectively,and the number of microbes,i.e.,bacteria,actinomycetes,and fungi by 36-150,11-153,and 43-56%,respectively.Further,organic fertilizer replacement had a Shannon's diversity index (H) of 2.18,which was higher than that of other modes of single N fertilizer application.The results suggested that reducing N fertilizer by 20% and applying organic manure in the experimental areas could effectively lower the production costs and significantly improve soil fertility and biological properties.展开更多
In the rice-wheat rotation system,biochar(BC)can be applied at the initiation of the rice or wheat season.Here,we compared the effects of BC that were applied at two different crop seasons on wheat production,quality,...In the rice-wheat rotation system,biochar(BC)can be applied at the initiation of the rice or wheat season.Here,we compared the effects of BC that were applied at two different crop seasons on wheat production,quality,and soil profile properties in a rice-wheat rotation system with nitrogen(N)fertilizer applied at 280 kg/ha rate.Results showed that both wheat grain production and N recovery use efficiency were influenced by BC applied at two crop seasons.Biochar application did not affect the total non-essential amino-acid,but when applied during wheat season,BC significantly(p<0.05)increased total essential amino acid in grain by 12.3%,particularly for the valine(+48.2%),methionine(+43.8%),and isoleucine(+10.3%).We found that BC significantly(p<0.05)decreased the pH of soil at 0–6 cm and 20–30 cm by 0.14–0.18 and 0.05–0.08 units,respectively.The NH4+-N content of the whole observed soil profile were reduced by BC application,however,the effect of BC on NO3–-N content varied with the application season and profile depth.Interestingly,BC applied at wheat and rice season significantly(p<0.05)improved topsoil N contents by 48.4%and 19.7%,respectively.In addition,data suggested that BC applied during wheat season performed better in enhancing soil available phosphorus,potassium,and organic matter contents.In conclusion,we suggest that the optimum application time of BC for enhancing crop production and quality(take amino-acid content for example)and improving soil fertility is at the initiation of the wheat season.展开更多
Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss...Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation (USLE) would supply a scientiifc basis for soil conservation planning. However, a lack of in-formation on the cover and management (C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios (SLRs) were col ected and quantiifed for 10 primary crops from past studies or re-ports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfal erosivity (R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for al 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was signiifcantly different from those in single and double zones. The C values of dryland crop systems exhibited signiifcant differences in the single and triple cropping system regions but the differences in the double regions were not signiifcant. This study is the ifrst report of the C values of crop rotation systems in China at the national scale. It wil provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.展开更多
Rice-wheat (R-W) rotation systems are ubiquitous in South and East Asia, and play an important role in modulating the carbon cycle and climate. Long-term, continuous flux measurements help in better understanding th...Rice-wheat (R-W) rotation systems are ubiquitous in South and East Asia, and play an important role in modulating the carbon cycle and climate. Long-term, continuous flux measurements help in better understanding the seasonal and interannual variation of the carbon budget over R-W rotation systems. In this study, measurements of CO2 fluxes and meteorological variables over an R-W rotation system on the North China Plain from 2007 to 2010 were analyzed. To analyze the abiotic factors regulating Net Ecosystem Exchange (NEE), NEE was partitioned into gross primary production (GPP) and ecosystem respiration. Nighttime NEE or ecosystem respiration was controlled primarily by soil temperature, while daytime NEE was mainly determined by photosythetically active radiation (PAR). The responses of nighttime NEE to soil temperature and daytime NEE to light were closely associated with crop development and photosynthetic activity, respectively. Moreover, the interannual variation in GPP and NEE mainly depended on precipitation and PAR. Overall, NEE was negative on the annual scale and the rotation system behaved as a carbon sink of 982 g C m 2 per year over the three years. The winter wheat field took up more CO2 than the rice paddy during the longer growing season, while the daily NEE for wheat and rice were -2.35 and -3.96 g C m-2, respectively. After the grain harvest was subtracted from the NEE, the winter wheat field became a moderately strong carbon sink of 251-334 g C m-2 per season, whereas the rice paddy switched to a weak carbon sink of 107-132 per season.展开更多
In order to numerically simulate daily nitrous oxide (N2O) emission from a rice-winter wheat rotation cropping system, a process-based site model was developed (referred to as IAP-N-GAS) to track the movement and ...In order to numerically simulate daily nitrous oxide (N2O) emission from a rice-winter wheat rotation cropping system, a process-based site model was developed (referred to as IAP-N-GAS) to track the movement and transformation of several forms of nitrogen in the agro-eeosystem, which is affected by climate, soil, crop growth and management practices. The simulation of daily N2O fluxes, along with key daily environmental variables, was validated with three-year observations conducted in East China. The validation demonstrated that the model simulated well daily solar radiation, soil temperature and moisture, and also captured the dynamics and magnitude of accumulated rice aboveground biomass and mineral nitrogen in the soil. The simulated daily N2O emissions over all three years investigated were generally in good agreement with field observations. Particularly well simulated were the peak N2O emissions induced by fertilizations, rainfall events or mid-season drainages. The model simulation also represented closely the inter-annuM variation in N2O emission. These validations imply that the model has the capability to capture the general characteristics of N2O emission from a typical rice-wheat rotation agro-ecosystem. Sensitivity analyses revealed that the simulated N2O emission is most sensitive to the fertilizer application rate and the soil organic matter content, but it is much less sensitive to variations in soil pH and texture, temperature, precipitation and crop residue incorporation rate under local conditions.展开更多
Rotational grazing is considered as one of the nature-based solutions(NbS)to grassland protection by natural scientists.However,its effects on improving grassland quality are still unclear when it is adopted by herder...Rotational grazing is considered as one of the nature-based solutions(NbS)to grassland protection by natural scientists.However,its effects on improving grassland quality are still unclear when it is adopted by herders.Using a householdlevel panel data from field survey in two main pastoral provinces of China,empirical results from fixed-effect model and instrumental approach show that rotational grazing practices have insignificant short-term effects on grassland quality,but have positive long-term effects.In addition,rotational grazing practices can improve grassland quality when villages invest public infrastructure or herders have private supporting measures for more efficiency livestock production.Further analysis shows that herders adopting rotational grazing have higher grazing intensity,higher supplementary intensity and more livestock-house-feeding days,which indicate herders can utilize more efficient livestock management without increasing pressure on natural grassland.We also find that herders with pastoral income are more likely to adopt rotational grazing practice.These insightful findings offer policy implications on promoting grassroot NbS for ecosystem protection and resource utilization in developing pastoral countries.展开更多
The Sun has solar rotation;nevertheless, many evidences have suggested that different latitude of the Sun rotates in different speed, which is now known as differential rotation. This work calculates the solar rotatio...The Sun has solar rotation;nevertheless, many evidences have suggested that different latitude of the Sun rotates in different speed, which is now known as differential rotation. This work calculates the solar rotation speeds near the equator and 30? in the northern hemisphere using Fixed-Point Arithmetic method. The calculated results show a greater speed at the equator than the speed at 30?, indicating that the speed decreases as the latitude becomes higher. .展开更多
To understand the CH_(4) flux variations and their climatic drivers in the rice-wheat agroecosystem in the Huai River Basin of China,the CH_(4) flux was observed by using open-path eddy covariance at a typical rice-wh...To understand the CH_(4) flux variations and their climatic drivers in the rice-wheat agroecosystem in the Huai River Basin of China,the CH_(4) flux was observed by using open-path eddy covariance at a typical rice-wheat rotation system in Anhui Province,China from November 2019 to October 2021.The variations and their drivers were then analyzed with the Akaike information criterion method.CH_(4) flux showed distinct diurnal variations with single peaks during 9:00-13:00 local time.The highest peak was 2.15μg m^(-2)s^(-1)which occurred at 11:00 in the vegetative growth stage in the rice growing season(RGS).CH_(4) flux also showed significant seasonal variations.The average CH_(4)flux in the vegetative growth stage in the RGS(193.8±74.2 mg m^(-2)d^(-1))was the highest among all growth stages.The annual total CH_(4) flux in the non-rice growing season(3.2 g m^(-2))was relatively small compared to that in the RGS(23.9 g m^(-2)).CH_(4) flux increased significantly with increase in air temperature,soil temperature,and soil water content in both the RGS and the non-RGS,while it decreased significantly with increase in vapor pressure deficit in the RGS.This study provided a comprehensive understanding of the CH_(4) flux and its drivers in the rice-wheat rotation agroecosystem in the Huai River Basin of China.In addition,our findings will be helpful for the validation and adjustment of the CH_(4) models in this region.展开更多
The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hinde...The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included: 1) creating a favorable environment and viable rotations; 2) balanced fertilization for maintenance of sustainable soil productivity; 3) improvement of crop management for higher efficiency; and 4) use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as: 1) the constant topic: a highly productive and efficient rice-wheat cropping system for sustainable growth; 2) the future trend: simplified cultivation techniques for the rice-wheat cropping system; 3) the foundation: basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.展开更多
[目的]探究山东省不同气候分区年降水量的时空特征,为该地区气候分析、防灾减灾提供更加区域性的参考依据。[方法]根据山东省95个国家地面气象观测站1991—2020年降水年值数据,首先对山东省年降水场进行气候分区,然后通过相关统计方法...[目的]探究山东省不同气候分区年降水量的时空特征,为该地区气候分析、防灾减灾提供更加区域性的参考依据。[方法]根据山东省95个国家地面气象观测站1991—2020年降水年值数据,首先对山东省年降水场进行气候分区,然后通过相关统计方法分析各分区降水的时空变化特征。[结果](1)山东省各降水模态降水偏少的年份更多,降水偏多的年份降水强度更大,年代际变化均较为明显,但各模态降水偏多偏少的年份分布及强度变化有所不同。(2)山东省年降水量大致由东南向西北递减,年降水场划分为东南沿海区(Ⅰ区)、西北平原区(Ⅱ区)和中部山地区(Ⅲ区)3个区域,各降水分区年降水均呈不显著增加趋势,趋势率各不相同,突变均不明显。(3)山东省各降水分区年降水量均具有较为明显的周期性特征,东南沿海区年降水场存在2个较为明显的能量中心,中心尺度均为2~3 a,未来变化具有强持续性;西北平原区年降水场存在3个较为明显的能量中心,中心尺度分别为5~7 a, 3 a和2~3 a,未来变化具有持续性;中部山地区年降水场存在2个较为明显的能量中心,中心尺度分别为2~3 a, 6 a,未来变化具有强持续性。[结论]山东省降水偏少的年份更多,降水偏多的年份降水强度更大,年降水场大致可分为3个分区,各分区年降水量均呈不显著增加趋势,均具有较为明显的周期性特征,且未来变化均具有持续性。展开更多
The rice-wheat rotation system plays a significant role in Asian agriculture.The introduction of strip-tillage into the rice-wheat system for wheat planting offers a way to use conservation tillage practices to improv...The rice-wheat rotation system plays a significant role in Asian agriculture.The introduction of strip-tillage into the rice-wheat system for wheat planting offers a way to use conservation tillage practices to improve the seedbed quality,retain residue between rows and reduce energy input.A field experiment was conducted using an in-situ test rig.Three types of blade(bent C,straight and hoe)were evaluated in four tool configurations at four rotary speeds(180 r/min,280 r/min,380 r/min and 510 r/min)in a paddy soil.Furrow shape parameters,tillage-induced soil structures and energy consumption were assessed.Results showed that the straight blade configuration failed to create a continuous furrow at either 180 r/min or 510 r/min.The bent C blade configuration produced a uniform furrow profile but its furrow backfill was poor and unsuitable for seeding.The hoe blade configuration cut a continuous furrow and better tillage-induced soil structure,but it produced a much wider and non-uniform furrow shape.The mixed blade configuration(central hoe blades with two straight blades aside)provided a uniform furrow with good backfill and fine tilth by utilizing both the cutting effect of straight blades on the furrow boundaries and tensile fracturing of the furrow soil by the hoe blades.The torque of the mixed blade configuration was comparable with the bent C blade but was less than the hoe blades.Hence,a mixed blade configuration was recommended for rotary strip-tillage seeding using in rice-wheat system.展开更多
It is of great significance to explore the effects of different tillage practices on total nitrogen and its components in rice-wheat rotation farmland.The experiment was carried out in Jiangyan County,Jiangsu Province...It is of great significance to explore the effects of different tillage practices on total nitrogen and its components in rice-wheat rotation farmland.The experiment was carried out in Jiangyan County,Jiangsu Province of China,and a total of four treatments were set up:minimum tillage(MT),rotary tillage(RT),conventional tillage(CT),and conventional tillage without straw retention(CT0).The total nitrogen(TN),light fraction nitrogen(LFN),heavy fraction nitrogen(HFN),particulate nitrogen(PN),and mineral-associated nitrogen(MN)in 0-20 cm soil were determined.The results show that MT increased TN concentration by2.26%-27.57%compared with the other treatments in 0-5 cm soil,but it lost this advantage in 5-10 cm and 10-20 cm soil.MT altered the concentration of LFN by 6.03%-95.86%,of HFN by 1.68%-20.75%,of PN by 12.58%-96.83%,and of MN by−1.73%-9.83%as compared to RT,CT,and CT0 in 0-5 cm soil,respectively.With the deepened of soil depth,the concentration of TN,LFN,HFN,PN,and MN decreased quickly in MT,which was lower than that in RT and CT at 10-20 cm soil depth.Straw return increased the concentration of TN and its components in 0-20 cm soil.The concentration of TN was extremely significantly positively correlated with that of LFN,HFN,PN,and MN(p<0.01).The variation of TN was significantly positively correlated with that of LFN,HFN,PN,and MN(p<0.01),and LFN showed the highest sensitivity to tillage practice.In general,minimum tillage combined with straw retention increased the concentration of soil TN and its components in topsoil.LFN was the best indicator to indicate the change in soil total nitrogen affected by tillage practice.展开更多
基金National Key Research and Development Program Fund of China(2016YFD0300107)Initiative Funds for Talented Scientists in Anhui Academy of Agricultural Sciences(16F0202).
文摘The present study was planned to analyze the yield gap of wheat and its production constraints in order to explore the approaches for narrowing the yield gap of wheat in different wheat-rice rotation regions of Anhui Province. The production status and limiting factors of wheat in three rice-wheat rotation regions which are named Region Ⅰ,Region Ⅱ and Region Ⅲ were surveyed by using participatory rural appraisal method. The personnel,who were engaged in wheat production in rice-wheat rotation regions of Anhui Province,mainly ageing from 41 to 60,accounted for 79% of the total personnel in the regions. There were significant differences in yield of wheat which was planted after rice in Anhui. The yield was ranging from 8 907. 00 to 2 700. 00 kg/ha from north to south with an average of 4 978. 5 kg/ha,and the rank of overall average yields at province level was Region Ⅰ( 5 685. 60 kg/ha) > Region Ⅱ( 5 600. 10 kg/ha) > Region Ⅲ( 3 048. 60 kg/ha). The average yield gap of wheat in wheat-rice rotation regions at province level was up to 2 637. 00 kg/ha,and the extreme yield gaps per hectare in the same region were 2 778. 00 kg( Region Ⅰ),2 502. 00 kg( Region Ⅱ) and 1 575. 00 kg( Region Ⅲ) respectively. The objective constraints were Fusarium head blight and pre-harvest sprouting;the subjective constraints were variety selection and layout,poor sowing quality and low seedling quality;social constraints were high cost,low market price and poor efficiency;and ecological constraints were poor soil texture,soil infertility and poor water-and-fertilizer retention. The yield gap of wheat in rice-wheat rotation regions can be effectively reduced by improving yield potential of low-and-medium-yielding fields. Selecting appropriate wheat varieties and layout,constructing disease forecast system,improving agricultural machinery and social service organizations of plant protection,and strengthening scientific training as well as technological training of new agricultural operators and agricultural machinery technicians are the core means to narrowing the yield gap of wheat in rice-wheat rotation regions at province scale.
文摘Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season. Rapeseed cake and wheat straw were incorporated into the soil at a rate of 2.25 t hm(-2) when the rice crop was transplanted in June 2001. Compared with the control, the incorporation of rapeseed cake enhanced the emissions of CO2, CH4, and N2O in the rice-growing season by 12.3%, 252.3%, and 17.5%, respectively, while no further effect was held on the emissions of CO2 and N2O in the following wheat-growing season. The incorporation of wheat straw enhanced the emissions of CO2 and CH4 by 7.1% and 249.6%, respectively, but reduced the N2O emission by 18.8% in the rice-growing season. Significant reductions of 17.8% for the CO2 and of 12.9% for the N2O emission were observed in the following wheat-growing season. A positive correlation existed between the emissions of N2O and CO2 (R-2 = 0.445, n = 73,p < 0.001) from the rice-growing season when N2O was emitted. A trade-off relationship between the emissions of CH4 and N2O was found in the rice-growing season. The CH4 emission was significantly correlated with the CO2 emission for the period from rice transplantation to field drainage, but not for the entire rice-growing season. In addition, air temperature was found to regulate the CO2 emissions from the non-waterlogged period over the entire rice-wheat rotation season and the N2O emissions from the nonwaterlogged period of the rice-growing season, which can be quantitatively described by an exponential function. The temperature coefficient (Q(10)) was then evaluated to be 2.3+/-0.2 for the CO2 emission and 3.9+/-0.4 for the N2O emission, respectively.
基金supported by the National Basic Research Program of China (973 Program,2007CB109308)the National High-Tech R&D Program of China (2007AA06Z332)a special grant of Application of Nuclear Techniques in Agriculture from the Ministry of Agriculture of China (200803034)
文摘Rational application of nitrogen (N) fertilizers is an important measure to raise N fertilizer recovery rate and reduce N loss.A two-year field experiment of rice-wheat rotation was employed to study the effects of N fertilization modes including a N fertilizer reduction and an organic manure replacement on crop yield,nutrient uptake,soil enzyme activity,and number of microbes as well as diversity of microbes.The result showed that 20% reduction of traditional N fertilizer dose of local farmers did not significantly change crop yield,N uptake,soil enzyme activity,and the number of microbes (bacteria,actinomycetes,and fungi).On the basis of 20% reduction of N fertilizer,50% replacement of N fertilizer by organic manure increased the activity of sucrose,protease,urease,and phosphatase by 46-62,27-89,33-46,and 35-74%,respectively,and the number of microbes,i.e.,bacteria,actinomycetes,and fungi by 36-150,11-153,and 43-56%,respectively.Further,organic fertilizer replacement had a Shannon's diversity index (H) of 2.18,which was higher than that of other modes of single N fertilizer application.The results suggested that reducing N fertilizer by 20% and applying organic manure in the experimental areas could effectively lower the production costs and significantly improve soil fertility and biological properties.
基金financially supported by the Higher Education Department of Guangdong Province (No.2020KCXTD025)the National Key Research and Development Program of China (No.2017YFD0800404).
文摘In the rice-wheat rotation system,biochar(BC)can be applied at the initiation of the rice or wheat season.Here,we compared the effects of BC that were applied at two different crop seasons on wheat production,quality,and soil profile properties in a rice-wheat rotation system with nitrogen(N)fertilizer applied at 280 kg/ha rate.Results showed that both wheat grain production and N recovery use efficiency were influenced by BC applied at two crop seasons.Biochar application did not affect the total non-essential amino-acid,but when applied during wheat season,BC significantly(p<0.05)increased total essential amino acid in grain by 12.3%,particularly for the valine(+48.2%),methionine(+43.8%),and isoleucine(+10.3%).We found that BC significantly(p<0.05)decreased the pH of soil at 0–6 cm and 20–30 cm by 0.14–0.18 and 0.05–0.08 units,respectively.The NH4+-N content of the whole observed soil profile were reduced by BC application,however,the effect of BC on NO3–-N content varied with the application season and profile depth.Interestingly,BC applied at wheat and rice season significantly(p<0.05)improved topsoil N contents by 48.4%and 19.7%,respectively.In addition,data suggested that BC applied during wheat season performed better in enhancing soil available phosphorus,potassium,and organic matter contents.In conclusion,we suggest that the optimum application time of BC for enhancing crop production and quality(take amino-acid content for example)and improving soil fertility is at the initiation of the wheat season.
基金financially supported by the Fund for Creative Research Groups of National Natural Science Foundation of China (41321001)
文摘Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation (USLE) would supply a scientiifc basis for soil conservation planning. However, a lack of in-formation on the cover and management (C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios (SLRs) were col ected and quantiifed for 10 primary crops from past studies or re-ports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfal erosivity (R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for al 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was signiifcantly different from those in single and double zones. The C values of dryland crop systems exhibited signiifcant differences in the single and triple cropping system regions but the differences in the double regions were not signiifcant. This study is the ifrst report of the C values of crop rotation systems in China at the national scale. It wil provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.
基金supported by the China Meteorological Administration (Grant No.GYHY201006024)the National Key Basic Research Program (Grant Nos.2010CB428502 and 2012CB417203)+2 种基金the Chinese Academy of Sciences Strategic Priority Research Program (Grant No.XDA05110101)the National Natural Science Foundation of China (Grant Nos.40975009 and 41405018)the State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences (Grant No.LAPC-KF-2009-02)
文摘Rice-wheat (R-W) rotation systems are ubiquitous in South and East Asia, and play an important role in modulating the carbon cycle and climate. Long-term, continuous flux measurements help in better understanding the seasonal and interannual variation of the carbon budget over R-W rotation systems. In this study, measurements of CO2 fluxes and meteorological variables over an R-W rotation system on the North China Plain from 2007 to 2010 were analyzed. To analyze the abiotic factors regulating Net Ecosystem Exchange (NEE), NEE was partitioned into gross primary production (GPP) and ecosystem respiration. Nighttime NEE or ecosystem respiration was controlled primarily by soil temperature, while daytime NEE was mainly determined by photosythetically active radiation (PAR). The responses of nighttime NEE to soil temperature and daytime NEE to light were closely associated with crop development and photosynthetic activity, respectively. Moreover, the interannual variation in GPP and NEE mainly depended on precipitation and PAR. Overall, NEE was negative on the annual scale and the rotation system behaved as a carbon sink of 982 g C m 2 per year over the three years. The winter wheat field took up more CO2 than the rice paddy during the longer growing season, while the daily NEE for wheat and rice were -2.35 and -3.96 g C m-2, respectively. After the grain harvest was subtracted from the NEE, the winter wheat field became a moderately strong carbon sink of 251-334 g C m-2 per season, whereas the rice paddy switched to a weak carbon sink of 107-132 per season.
基金supported by the Chinese Academy of Sciences (KZCX2-YW-204, KSCX3-SW-440, KZCX1-SW-01)the National Natural Science Foundation of China (40425010, 40331014)+1 种基金the European Union (NitroEurope IP 017841)the Helmholtz Society via the Sino-German Joint Laboratory project ENTRANCE
文摘In order to numerically simulate daily nitrous oxide (N2O) emission from a rice-winter wheat rotation cropping system, a process-based site model was developed (referred to as IAP-N-GAS) to track the movement and transformation of several forms of nitrogen in the agro-eeosystem, which is affected by climate, soil, crop growth and management practices. The simulation of daily N2O fluxes, along with key daily environmental variables, was validated with three-year observations conducted in East China. The validation demonstrated that the model simulated well daily solar radiation, soil temperature and moisture, and also captured the dynamics and magnitude of accumulated rice aboveground biomass and mineral nitrogen in the soil. The simulated daily N2O emissions over all three years investigated were generally in good agreement with field observations. Particularly well simulated were the peak N2O emissions induced by fertilizations, rainfall events or mid-season drainages. The model simulation also represented closely the inter-annuM variation in N2O emission. These validations imply that the model has the capability to capture the general characteristics of N2O emission from a typical rice-wheat rotation agro-ecosystem. Sensitivity analyses revealed that the simulated N2O emission is most sensitive to the fertilizer application rate and the soil organic matter content, but it is much less sensitive to variations in soil pH and texture, temperature, precipitation and crop residue incorporation rate under local conditions.
基金supported by the National Natural Science Foundation of China(72173004 and 71773003)the Major Consulting Project of Chinese Academy of Engineering(2022-HZ-09)。
文摘Rotational grazing is considered as one of the nature-based solutions(NbS)to grassland protection by natural scientists.However,its effects on improving grassland quality are still unclear when it is adopted by herders.Using a householdlevel panel data from field survey in two main pastoral provinces of China,empirical results from fixed-effect model and instrumental approach show that rotational grazing practices have insignificant short-term effects on grassland quality,but have positive long-term effects.In addition,rotational grazing practices can improve grassland quality when villages invest public infrastructure or herders have private supporting measures for more efficiency livestock production.Further analysis shows that herders adopting rotational grazing have higher grazing intensity,higher supplementary intensity and more livestock-house-feeding days,which indicate herders can utilize more efficient livestock management without increasing pressure on natural grassland.We also find that herders with pastoral income are more likely to adopt rotational grazing practice.These insightful findings offer policy implications on promoting grassroot NbS for ecosystem protection and resource utilization in developing pastoral countries.
文摘The Sun has solar rotation;nevertheless, many evidences have suggested that different latitude of the Sun rotates in different speed, which is now known as differential rotation. This work calculates the solar rotation speeds near the equator and 30? in the northern hemisphere using Fixed-Point Arithmetic method. The calculated results show a greater speed at the equator than the speed at 30?, indicating that the speed decreases as the latitude becomes higher. .
基金supported by the Natural Science Foundation of Jiangsu Province,China(BK20220017)the Innovation Development Project of China Meteorological Administration(CXFZ2023J073)+1 种基金the Key Research and Development Program of Anhui Province,China(2022M07020003)the Graduate Student Practice and Innovation Program of Jiangsu Province,China(SJCX22_0374)。
文摘To understand the CH_(4) flux variations and their climatic drivers in the rice-wheat agroecosystem in the Huai River Basin of China,the CH_(4) flux was observed by using open-path eddy covariance at a typical rice-wheat rotation system in Anhui Province,China from November 2019 to October 2021.The variations and their drivers were then analyzed with the Akaike information criterion method.CH_(4) flux showed distinct diurnal variations with single peaks during 9:00-13:00 local time.The highest peak was 2.15μg m^(-2)s^(-1)which occurred at 11:00 in the vegetative growth stage in the rice growing season(RGS).CH_(4) flux also showed significant seasonal variations.The average CH_(4)flux in the vegetative growth stage in the RGS(193.8±74.2 mg m^(-2)d^(-1))was the highest among all growth stages.The annual total CH_(4) flux in the non-rice growing season(3.2 g m^(-2))was relatively small compared to that in the RGS(23.9 g m^(-2)).CH_(4) flux increased significantly with increase in air temperature,soil temperature,and soil water content in both the RGS and the non-RGS,while it decreased significantly with increase in vapor pressure deficit in the RGS.This study provided a comprehensive understanding of the CH_(4) flux and its drivers in the rice-wheat rotation agroecosystem in the Huai River Basin of China.In addition,our findings will be helpful for the validation and adjustment of the CH_(4) models in this region.
基金funded by the National Key Technologies Research and Development Program of China(2006BAD02A05)the Science and Technology Project for Public (Agriculture)the Ministry of Agriculture, China (200903050-4)
文摘The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included: 1) creating a favorable environment and viable rotations; 2) balanced fertilization for maintenance of sustainable soil productivity; 3) improvement of crop management for higher efficiency; and 4) use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as: 1) the constant topic: a highly productive and efficient rice-wheat cropping system for sustainable growth; 2) the future trend: simplified cultivation techniques for the rice-wheat cropping system; 3) the foundation: basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.
文摘[目的]探究山东省不同气候分区年降水量的时空特征,为该地区气候分析、防灾减灾提供更加区域性的参考依据。[方法]根据山东省95个国家地面气象观测站1991—2020年降水年值数据,首先对山东省年降水场进行气候分区,然后通过相关统计方法分析各分区降水的时空变化特征。[结果](1)山东省各降水模态降水偏少的年份更多,降水偏多的年份降水强度更大,年代际变化均较为明显,但各模态降水偏多偏少的年份分布及强度变化有所不同。(2)山东省年降水量大致由东南向西北递减,年降水场划分为东南沿海区(Ⅰ区)、西北平原区(Ⅱ区)和中部山地区(Ⅲ区)3个区域,各降水分区年降水均呈不显著增加趋势,趋势率各不相同,突变均不明显。(3)山东省各降水分区年降水量均具有较为明显的周期性特征,东南沿海区年降水场存在2个较为明显的能量中心,中心尺度均为2~3 a,未来变化具有强持续性;西北平原区年降水场存在3个较为明显的能量中心,中心尺度分别为5~7 a, 3 a和2~3 a,未来变化具有持续性;中部山地区年降水场存在2个较为明显的能量中心,中心尺度分别为2~3 a, 6 a,未来变化具有强持续性。[结论]山东省降水偏少的年份更多,降水偏多的年份降水强度更大,年降水场大致可分为3个分区,各分区年降水量均呈不显著增加趋势,均具有较为明显的周期性特征,且未来变化均具有持续性。
基金supported by the State Key Program of China(2016 YFD 0300900)Jiangsu Agri.Mech.Fund(201-051028).
文摘The rice-wheat rotation system plays a significant role in Asian agriculture.The introduction of strip-tillage into the rice-wheat system for wheat planting offers a way to use conservation tillage practices to improve the seedbed quality,retain residue between rows and reduce energy input.A field experiment was conducted using an in-situ test rig.Three types of blade(bent C,straight and hoe)were evaluated in four tool configurations at four rotary speeds(180 r/min,280 r/min,380 r/min and 510 r/min)in a paddy soil.Furrow shape parameters,tillage-induced soil structures and energy consumption were assessed.Results showed that the straight blade configuration failed to create a continuous furrow at either 180 r/min or 510 r/min.The bent C blade configuration produced a uniform furrow profile but its furrow backfill was poor and unsuitable for seeding.The hoe blade configuration cut a continuous furrow and better tillage-induced soil structure,but it produced a much wider and non-uniform furrow shape.The mixed blade configuration(central hoe blades with two straight blades aside)provided a uniform furrow with good backfill and fine tilth by utilizing both the cutting effect of straight blades on the furrow boundaries and tensile fracturing of the furrow soil by the hoe blades.The torque of the mixed blade configuration was comparable with the bent C blade but was less than the hoe blades.Hence,a mixed blade configuration was recommended for rotary strip-tillage seeding using in rice-wheat system.
基金This study was partially supported by A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the National Key R&D Program of China(Grant No.2018YFD0200500)the Special Technology Innovation Fund of Carbon Peak and Carbon Neutrality in Jiangsu Province(BE2022312)+1 种基金the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(Agricultural Academy Office(2014)No.216)the Fundamental Research Funds for the Central Public Research Institutes(Grant No.S202010-02).
文摘It is of great significance to explore the effects of different tillage practices on total nitrogen and its components in rice-wheat rotation farmland.The experiment was carried out in Jiangyan County,Jiangsu Province of China,and a total of four treatments were set up:minimum tillage(MT),rotary tillage(RT),conventional tillage(CT),and conventional tillage without straw retention(CT0).The total nitrogen(TN),light fraction nitrogen(LFN),heavy fraction nitrogen(HFN),particulate nitrogen(PN),and mineral-associated nitrogen(MN)in 0-20 cm soil were determined.The results show that MT increased TN concentration by2.26%-27.57%compared with the other treatments in 0-5 cm soil,but it lost this advantage in 5-10 cm and 10-20 cm soil.MT altered the concentration of LFN by 6.03%-95.86%,of HFN by 1.68%-20.75%,of PN by 12.58%-96.83%,and of MN by−1.73%-9.83%as compared to RT,CT,and CT0 in 0-5 cm soil,respectively.With the deepened of soil depth,the concentration of TN,LFN,HFN,PN,and MN decreased quickly in MT,which was lower than that in RT and CT at 10-20 cm soil depth.Straw return increased the concentration of TN and its components in 0-20 cm soil.The concentration of TN was extremely significantly positively correlated with that of LFN,HFN,PN,and MN(p<0.01).The variation of TN was significantly positively correlated with that of LFN,HFN,PN,and MN(p<0.01),and LFN showed the highest sensitivity to tillage practice.In general,minimum tillage combined with straw retention increased the concentration of soil TN and its components in topsoil.LFN was the best indicator to indicate the change in soil total nitrogen affected by tillage practice.