Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 pub...Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha^(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha^(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.展开更多
Although wastewater irrigation in agriculture could be a potential adaptation to water scarcity, its effect on crop yield varies in the literature, making it difficult to evaluate its role in global food security comp...Although wastewater irrigation in agriculture could be a potential adaptation to water scarcity, its effect on crop yield varies in the literature, making it difficult to evaluate its role in global food security comprehensively. Using agronomic experiment data from 62 studies between 1987 and 2021, we employ a meta-analysis to analyze the factors contributing to the heterogeneous effects of wastewater irrigation on crop yield. Our findings can be summarized as(1) the mean yield growth effect of wastewater irrigation is 19.7%;(2) domestic and breeding wastewater irrigation could significantly increase crop yield, while industrial wastewater has a negative effect although not significant;(3) high nutrients concentration of domestic wastewater is significantly positively correlated with crop yield;(4) agronomic experiment designs in terms of field experiment, experiment times, and fertilizer use could contribute to the divergent crop yield effects across the studies;(5) there is a publication bias of the research results between the English and Chinese literature;(6) the literature mainly sheds light on the short-run effect, and the long-run impact shall be an important research question in the future.展开更多
Compost amendments have remarkable potential for improving soil structure, porosity and water holding capacity. Soil health is the ability to function as a living system, to sustain plant and animal productivity, to e...Compost amendments have remarkable potential for improving soil structure, porosity and water holding capacity. Soil health is the ability to function as a living system, to sustain plant and animal productivity, to enhance water and air quality, and to promote plant and animal health. Soil health can be estimated by measuring the total living microbial biomass, retained carbon, odor, and texture. Poor or deteriorating soil health is threatening food security. The potential for compost to reverse these negative trends is transformative if means and methods for large scale composting and compost amendments can be developed. A field-scale compost soil amendment project was implemented in Rapid City, South Dakota. The compost was added to a soil plot at 5 wt% and 10 wt% and the results were compared with an adjacent untreated plot without any compost addition. Measurements of soil health characteristics indicate that compost amendments improve soil health, crop yields, and soil water content. Treating soils with compost has the potential to reverse global deteriorating soil health.展开更多
Changes in rice production in Southern China are crucial to national food security.This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015.The impa...Changes in rice production in Southern China are crucial to national food security.This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015.The impact of rice multiple cropping index changes on grain production capacity was then evaluated.Three important results were obtained for the 1990 to 2015 study period.First,the multiple cropping index for rice decreased from 148.3% to 129.3%,and 253.16×10^4 ha of land area was converted from double-cropping to single- cropping rice,termed “double to single”.The area with the most dramatic changes is in the Middle-Lower Yangtze Plain.The rice-cropping system distribution in Southern China showed a change from north to south with double-cropping rice shrinking and single-cropping rice expanding.Second,the “double to single” conversion led to a reduction of 6.1% and 2.6% in rice and grain production,respectively.Hunan and Jiangxi Provinces,located in the main rice producing areas,and Zhejiang,which has shown better economic development,exhibited large reductions in rice production due to the “double to single” conversion,all exceeding 13%.Third,the grain production capacity of converted “double to single” paddy fields is equivalent to that of 223.3 × 10^4 ha of newly reclaimed cultivated land,which is 54% of the total newly cultivated land reclaimed through the 2001–2015 land consolidation project.It is also 1.7 times the target goal for newly cultivated land in the national land consolidation plan for 2016–2020.Making full use of the converted “double to single” paddy fields can save 167.44 billion yuan in newly reclaimed cultivated land costs.Therefore,instead of pursuing low-quality new arable land,it is better to make full use of the existing high-quality arable land.Based on these results,the government should change the assessment method for cultivated land balance,and incorporate the sown area increased by improving the multiple cropping index into the cultivated land compensation indicator.展开更多
Raising the level of the multiple cropping index （MCI） plays a critical role in food production of China. Therefore, exploring the spatiotemporal differences and factors of the MCI in China is of important practical...Raising the level of the multiple cropping index （MCI） plays a critical role in food production of China. Therefore, exploring the spatiotemporal differences and factors of the MCI in China is of important practical significance. This paper examines the trend of multiple cropping index （MCI） changes in China at the national, regional and provincial levels during 1998-2012. Based on the Theil index, this paper explores the spatiotemporal differences of the MCI in China. Additionally, a spatial econometric model is used to identify the determi- nants of the spatiotemporal differences of the MCI from a behavioral perspective. The results are summarized as follows： （1） From the national perspective, the MCI shows an increasing trend year by year, rising from 120.1% in 1998 to 134.26% in 2012; （2） at the regional level, the northeastern region is the fastest growing area in terms of MCI, whereas the central region is the slowest growing area. The central region has the highest MCI level, whereas the northeastern region is connected to the lowest MCI level; （3） according to the Theil index value, the differences in the MCI show a narrowing trend from 0.11 in 1998 to 0.03 in 2012, which is primarily attributed to the differences among the four regions; （4） the MCI shows differences among China＇s 31 provinces, and the gap that it shows is great; and （5） the proportion of non-agricultural population has a significant negative effect on the MCI. However, the proportions of non-agricultural industry, agricultural policy, per capita operating arable land area and rural household per capita net income have a significant positive impact on the MCI. Therefore, the following policies are suggested to increase the level of China＇s cultivated land MCI： transferring rural surplus labor, increasing the farmers＇ income, accelerating the transfer of the use rights of arable land, developing the scale effect of land use, providing further support and benefits to farmers in less developed regions and major grain-producing areas, and strengthening the role of the national agricultural policy.展开更多
In wetland ecosystem, nitrogen along with other elements and its management is most imperative for the production of so many aquatic food, non-food and beneficial medicinal plants and for the improvement of soil and w...In wetland ecosystem, nitrogen along with other elements and its management is most imperative for the production of so many aquatic food, non-food and beneficial medicinal plants and for the improvement of soil and water characteristics. With great significant importance of INM (integrated nutrient management) as sources, emphasizing on management on nitrogen as a key element and its divergence, a case study was undertaken on such aquatic food crops (starch and protein-rich, most popular and remunerative) in the farmers' field of low-lying 'Tal' situation of New Alluvial Zone of Indian subtropics. The study was designed in factorial randomized block design, where, three important aquatic food crops (water chestnut (Trapa bispinosa Roxb.), makhana (Euryale ferox Salisb.) and water lily (Nymphaea spp.) as major factor and eleven combinations of organic and inorganic sources of nutrients as sub-factor was considered in the experiment. It revealed from the results that the production of fresh kernels or nuts of water chestnut (8.571 ha-1), matured nut yield of makhana (3.06 t ha-1) and flower stalks of water-lily as vegetables (6.38 t ha-1) including its nutritional quality (starch, protein, sugar and minerals) was remarkably influenced with the application of both organic (neem oilcake @ 0.2 t ha-1) and inorganic sources (NPK @ 30:20:20 kg ha-1 along with spraying of NPK @ 0.5% each over crop canopy at 20 days interval after transplanting) than the other INM combinations applied to the crops. Among the crops, highest WCYE (water chestnut yield equivalence) exhibited in makhana due to its high price of popped-form in the country, which is being exported to other countries at now. Sole application of both (organic and inorganic sources) with lower range did not produce any significant outcome from the study and exhibited lower value for all the crops. Besides production of food crops, INM also greatly influenced the soil and water characterization and it was favourably reflected in this study. The physico-chemical characteristics of soil (textural class, pH, organic carbon, organic matter, ammoniacal nitrogen, nitrate nitrogen, available nitrogen, phosphorus and potassium) are most important and contributed a significant improvement due to cultivation of these aquatic crops. Analysis of such wet bodies represented the water characteristics (pH, BOD, COD, CO3 =, HCO3-, NO3- N, SO4-S and Cl-) were most responsive, adaptable and quite favourable for the cultivation of these crops in this vast waste unused wetlands for the mankind without any environmental degradation.展开更多
针对西北绿洲灌区小麦连作普遍、化肥施用量较大及氮素利用率低等问题,探究麦后复种绿肥对减量施氮小麦籽粒产量和氮素利用的补偿效应,以期为构建减氮小麦高效生产技术提供理论依据。本研究依托始于2018年的定位试验进行,2020-2022年期...针对西北绿洲灌区小麦连作普遍、化肥施用量较大及氮素利用率低等问题,探究麦后复种绿肥对减量施氮小麦籽粒产量和氮素利用的补偿效应,以期为构建减氮小麦高效生产技术提供理论依据。本研究依托始于2018年的定位试验进行,2020-2022年期间采集数据。试验采用裂区设计,主区设4种绿肥种植模式,即麦后分别复种毛叶苕子混播箭筈豌豆(HCV)、箭筈豌豆(CV)、油菜(R)和麦后休闲(F);副区为3种施氮水平:试区习惯施氮量(N3,180 kg hm^(–2))、习惯施氮减量20%(N2,144 kg hm^(-2))、习惯施氮减量40%(N1,108 kg hm^(-2))。研究表明,习惯施氮减量20%和40%显著降低了小麦籽粒产量和氮素吸收,但麦后复种毛叶苕子混播箭筈豌豆可补偿因减量施氮40%造成的籽粒产量和氮素吸收损失,且麦后复种毛叶苕子混播箭筈豌豆结合减量施氮20%提高小麦籽粒产量21.4%和氮素吸收6.9%(P<0.05)。麦后复种毛叶苕子混播箭筈豌豆可补偿因减量施氮40%造成的氮素利用率损失,且其结合减量施氮20%氮素利用率提高13.4%(P<0.05)。其补偿机制归因于:(1)麦后复种毛叶苕子混播箭筈豌豆在减量施氮40%条件下可补偿小麦氮素吸收速率,提高氮素净同化速率34.3%(P<0.05),维持穗部氮素分配,增加茎氮素转运率6.6%(P<0.05)。(2)与麦后休闲传统施氮量相比,麦后复种毛叶苕子混播箭筈豌豆结合减量施氮20%提高氮素平均吸收速率和氮素净同化速率7.2%和34.1%(P<0.05),增加灌浆初期至成熟期穗氮素分配6.7%(P<0.05),提高叶、茎氮素对穗的转运贡献率17.8%、8.9%(P<0.05)。因此,在干旱绿洲灌区,麦后复种毛叶苕子混播箭筈豌豆是实现小麦减氮40%的可行措施,麦后复种毛叶苕子混播箭筈豌豆结合减氮20%可通过提高小麦氮素吸收速率和氮素净同化率,提高叶、茎对穗的转运贡献率从而促进穗部氮素分配,实现小麦产量和氮素利用率双提升。展开更多
With a continuously increasing population and better food consumption levels, im- proving the efficiency of arable land use and increasing its productivity have become funda- mental strategies to meet the growing food...With a continuously increasing population and better food consumption levels, im- proving the efficiency of arable land use and increasing its productivity have become funda- mental strategies to meet the growing food security needs in China. A spatial distribution map of medium- and low-yield cropland is necessary to implement plans for cropland improvement In this study, we developed a new method to identify high-, medium-, and low-yield cropland from Moderate Resolution Imaging Spectroradiometer （MODIS） data at a spatial resolution of 500 m. The method could be used to reflect the regional heterogeneity of cropland productiv- ity because the classification standard was based on the regionalization of cropping systems in China. The results showed that the proportion of high-, medium-, and low-yield cropland in China was 21%, 39%, and 40%, respectively. About 75% of the low-yield cropland was lo- cated in hilly and mountainous areas, and about 53% of the high-yield cropland was located in plain areas. The five provinces with the largest area of high-yield cropland were all located in the Huang-Huai-Hai region, and the area amounted to 42% of the national high-yield cropland area. Meanwhile, the proportion of high-yield cropland was lower than 15% in Hei- Iongjiang, Sichuan, and Inner Mongolia, which had the largest area allocated to cropland in China. If all the medium-yield cropland could be improved to the productive level of high-yield cropland and the low-yield cropland could be improved to the level of medium-yield cropland, the total productivity of the land would increase 19% and 24%, respectively.展开更多
基金supported by the National Key Research and Development Program of China(2016YFD0300100)the Innovation Program of Chinese Academy of Agricultural Sciencesthe Elite Youth Program of the Chinese Academy of Agricultural Science。
文摘Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha^(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha^(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.
基金supported by the National Social Science Fund of China(20CSH048,20AZD024 and 21ZDA062)the National Natural Science Foundation of China(71773099)+1 种基金the Humanities and Social Sciences Project Funded by the Ministry of Education,China(21YJC790110)the Rural Finance Survey of the Ministry of Agriculture and Rural Affairs,China(05190084)。
文摘Although wastewater irrigation in agriculture could be a potential adaptation to water scarcity, its effect on crop yield varies in the literature, making it difficult to evaluate its role in global food security comprehensively. Using agronomic experiment data from 62 studies between 1987 and 2021, we employ a meta-analysis to analyze the factors contributing to the heterogeneous effects of wastewater irrigation on crop yield. Our findings can be summarized as(1) the mean yield growth effect of wastewater irrigation is 19.7%;(2) domestic and breeding wastewater irrigation could significantly increase crop yield, while industrial wastewater has a negative effect although not significant;(3) high nutrients concentration of domestic wastewater is significantly positively correlated with crop yield;(4) agronomic experiment designs in terms of field experiment, experiment times, and fertilizer use could contribute to the divergent crop yield effects across the studies;(5) there is a publication bias of the research results between the English and Chinese literature;(6) the literature mainly sheds light on the short-run effect, and the long-run impact shall be an important research question in the future.
文摘Compost amendments have remarkable potential for improving soil structure, porosity and water holding capacity. Soil health is the ability to function as a living system, to sustain plant and animal productivity, to enhance water and air quality, and to promote plant and animal health. Soil health can be estimated by measuring the total living microbial biomass, retained carbon, odor, and texture. Poor or deteriorating soil health is threatening food security. The potential for compost to reverse these negative trends is transformative if means and methods for large scale composting and compost amendments can be developed. A field-scale compost soil amendment project was implemented in Rapid City, South Dakota. The compost was added to a soil plot at 5 wt% and 10 wt% and the results were compared with an adjacent untreated plot without any compost addition. Measurements of soil health characteristics indicate that compost amendments improve soil health, crop yields, and soil water content. Treating soils with compost has the potential to reverse global deteriorating soil health.
基金National Natural Science Foundation of China,No.41571095,No.41161140352
文摘Changes in rice production in Southern China are crucial to national food security.This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015.The impact of rice multiple cropping index changes on grain production capacity was then evaluated.Three important results were obtained for the 1990 to 2015 study period.First,the multiple cropping index for rice decreased from 148.3% to 129.3%,and 253.16×10^4 ha of land area was converted from double-cropping to single- cropping rice,termed “double to single”.The area with the most dramatic changes is in the Middle-Lower Yangtze Plain.The rice-cropping system distribution in Southern China showed a change from north to south with double-cropping rice shrinking and single-cropping rice expanding.Second,the “double to single” conversion led to a reduction of 6.1% and 2.6% in rice and grain production,respectively.Hunan and Jiangxi Provinces,located in the main rice producing areas,and Zhejiang,which has shown better economic development,exhibited large reductions in rice production due to the “double to single” conversion,all exceeding 13%.Third,the grain production capacity of converted “double to single” paddy fields is equivalent to that of 223.3 × 10^4 ha of newly reclaimed cultivated land,which is 54% of the total newly cultivated land reclaimed through the 2001–2015 land consolidation project.It is also 1.7 times the target goal for newly cultivated land in the national land consolidation plan for 2016–2020.Making full use of the converted “double to single” paddy fields can save 167.44 billion yuan in newly reclaimed cultivated land costs.Therefore,instead of pursuing low-quality new arable land,it is better to make full use of the existing high-quality arable land.Based on these results,the government should change the assessment method for cultivated land balance,and incorporate the sown area increased by improving the multiple cropping index into the cultivated land compensation indicator.
基金National Natural Science Foundation of China, No.41361111 Science Foundation of Jiangxi Province, No.20143ACB21023, No.20142BAB203028+1 种基金 Fok Ying-Tung Fund, No.141084 Technology Foundation of Jiangxi Education Department of China, No.KJLD 14033
文摘Raising the level of the multiple cropping index （MCI） plays a critical role in food production of China. Therefore, exploring the spatiotemporal differences and factors of the MCI in China is of important practical significance. This paper examines the trend of multiple cropping index （MCI） changes in China at the national, regional and provincial levels during 1998-2012. Based on the Theil index, this paper explores the spatiotemporal differences of the MCI in China. Additionally, a spatial econometric model is used to identify the determi- nants of the spatiotemporal differences of the MCI from a behavioral perspective. The results are summarized as follows： （1） From the national perspective, the MCI shows an increasing trend year by year, rising from 120.1% in 1998 to 134.26% in 2012; （2） at the regional level, the northeastern region is the fastest growing area in terms of MCI, whereas the central region is the slowest growing area. The central region has the highest MCI level, whereas the northeastern region is connected to the lowest MCI level; （3） according to the Theil index value, the differences in the MCI show a narrowing trend from 0.11 in 1998 to 0.03 in 2012, which is primarily attributed to the differences among the four regions; （4） the MCI shows differences among China＇s 31 provinces, and the gap that it shows is great; and （5） the proportion of non-agricultural population has a significant negative effect on the MCI. However, the proportions of non-agricultural industry, agricultural policy, per capita operating arable land area and rural household per capita net income have a significant positive impact on the MCI. Therefore, the following policies are suggested to increase the level of China＇s cultivated land MCI： transferring rural surplus labor, increasing the farmers＇ income, accelerating the transfer of the use rights of arable land, developing the scale effect of land use, providing further support and benefits to farmers in less developed regions and major grain-producing areas, and strengthening the role of the national agricultural policy.
文摘In wetland ecosystem, nitrogen along with other elements and its management is most imperative for the production of so many aquatic food, non-food and beneficial medicinal plants and for the improvement of soil and water characteristics. With great significant importance of INM (integrated nutrient management) as sources, emphasizing on management on nitrogen as a key element and its divergence, a case study was undertaken on such aquatic food crops (starch and protein-rich, most popular and remunerative) in the farmers' field of low-lying 'Tal' situation of New Alluvial Zone of Indian subtropics. The study was designed in factorial randomized block design, where, three important aquatic food crops (water chestnut (Trapa bispinosa Roxb.), makhana (Euryale ferox Salisb.) and water lily (Nymphaea spp.) as major factor and eleven combinations of organic and inorganic sources of nutrients as sub-factor was considered in the experiment. It revealed from the results that the production of fresh kernels or nuts of water chestnut (8.571 ha-1), matured nut yield of makhana (3.06 t ha-1) and flower stalks of water-lily as vegetables (6.38 t ha-1) including its nutritional quality (starch, protein, sugar and minerals) was remarkably influenced with the application of both organic (neem oilcake @ 0.2 t ha-1) and inorganic sources (NPK @ 30:20:20 kg ha-1 along with spraying of NPK @ 0.5% each over crop canopy at 20 days interval after transplanting) than the other INM combinations applied to the crops. Among the crops, highest WCYE (water chestnut yield equivalence) exhibited in makhana due to its high price of popped-form in the country, which is being exported to other countries at now. Sole application of both (organic and inorganic sources) with lower range did not produce any significant outcome from the study and exhibited lower value for all the crops. Besides production of food crops, INM also greatly influenced the soil and water characterization and it was favourably reflected in this study. The physico-chemical characteristics of soil (textural class, pH, organic carbon, organic matter, ammoniacal nitrogen, nitrate nitrogen, available nitrogen, phosphorus and potassium) are most important and contributed a significant improvement due to cultivation of these aquatic crops. Analysis of such wet bodies represented the water characteristics (pH, BOD, COD, CO3 =, HCO3-, NO3- N, SO4-S and Cl-) were most responsive, adaptable and quite favourable for the cultivation of these crops in this vast waste unused wetlands for the mankind without any environmental degradation.
文摘针对西北绿洲灌区小麦连作普遍、化肥施用量较大及氮素利用率低等问题,探究麦后复种绿肥对减量施氮小麦籽粒产量和氮素利用的补偿效应,以期为构建减氮小麦高效生产技术提供理论依据。本研究依托始于2018年的定位试验进行,2020-2022年期间采集数据。试验采用裂区设计,主区设4种绿肥种植模式,即麦后分别复种毛叶苕子混播箭筈豌豆(HCV)、箭筈豌豆(CV)、油菜(R)和麦后休闲(F);副区为3种施氮水平:试区习惯施氮量(N3,180 kg hm^(–2))、习惯施氮减量20%(N2,144 kg hm^(-2))、习惯施氮减量40%(N1,108 kg hm^(-2))。研究表明,习惯施氮减量20%和40%显著降低了小麦籽粒产量和氮素吸收,但麦后复种毛叶苕子混播箭筈豌豆可补偿因减量施氮40%造成的籽粒产量和氮素吸收损失,且麦后复种毛叶苕子混播箭筈豌豆结合减量施氮20%提高小麦籽粒产量21.4%和氮素吸收6.9%(P<0.05)。麦后复种毛叶苕子混播箭筈豌豆可补偿因减量施氮40%造成的氮素利用率损失,且其结合减量施氮20%氮素利用率提高13.4%(P<0.05)。其补偿机制归因于:(1)麦后复种毛叶苕子混播箭筈豌豆在减量施氮40%条件下可补偿小麦氮素吸收速率,提高氮素净同化速率34.3%(P<0.05),维持穗部氮素分配,增加茎氮素转运率6.6%(P<0.05)。(2)与麦后休闲传统施氮量相比,麦后复种毛叶苕子混播箭筈豌豆结合减量施氮20%提高氮素平均吸收速率和氮素净同化速率7.2%和34.1%(P<0.05),增加灌浆初期至成熟期穗氮素分配6.7%(P<0.05),提高叶、茎氮素对穗的转运贡献率17.8%、8.9%(P<0.05)。因此,在干旱绿洲灌区,麦后复种毛叶苕子混播箭筈豌豆是实现小麦减氮40%的可行措施,麦后复种毛叶苕子混播箭筈豌豆结合减氮20%可通过提高小麦氮素吸收速率和氮素净同化率,提高叶、茎对穗的转运贡献率从而促进穗部氮素分配,实现小麦产量和氮素利用率双提升。
基金STS Project of CAS,No.KFJ-EW-STS-001National Natural Science Foundation of China,No.41430861
文摘With a continuously increasing population and better food consumption levels, im- proving the efficiency of arable land use and increasing its productivity have become funda- mental strategies to meet the growing food security needs in China. A spatial distribution map of medium- and low-yield cropland is necessary to implement plans for cropland improvement In this study, we developed a new method to identify high-, medium-, and low-yield cropland from Moderate Resolution Imaging Spectroradiometer （MODIS） data at a spatial resolution of 500 m. The method could be used to reflect the regional heterogeneity of cropland productiv- ity because the classification standard was based on the regionalization of cropping systems in China. The results showed that the proportion of high-, medium-, and low-yield cropland in China was 21%, 39%, and 40%, respectively. About 75% of the low-yield cropland was lo- cated in hilly and mountainous areas, and about 53% of the high-yield cropland was located in plain areas. The five provinces with the largest area of high-yield cropland were all located in the Huang-Huai-Hai region, and the area amounted to 42% of the national high-yield cropland area. Meanwhile, the proportion of high-yield cropland was lower than 15% in Hei- Iongjiang, Sichuan, and Inner Mongolia, which had the largest area allocated to cropland in China. If all the medium-yield cropland could be improved to the productive level of high-yield cropland and the low-yield cropland could be improved to the level of medium-yield cropland, the total productivity of the land would increase 19% and 24%, respectively.
