The GM(1,1)grey model was used to simulate and divide the harvest years of black-skinned sugarcane yield in Wengyuan County during 2006-2021.Based on the meteorological observation data of Wengyuan County during the s...The GM(1,1)grey model was used to simulate and divide the harvest years of black-skinned sugarcane yield in Wengyuan County during 2006-2021.Based on the meteorological observation data of Wengyuan County during the same period,the impact of major meteorological disasters such as drought,flood and frost in the growth period of black-skinned sugarcane was analyzed.It is believed that the instability of black-skinned sugarcane yield was affected by comprehensive meteorological factors.It is necessary to master the characteristics of local meteorological disasters,conduct scientific cultivation according to local conditions,and continuously improve the meteorological service level of black-skinned sugarcane cultivation.展开更多
A simplified water balance model in conjunc- tion with an evapotranspiration （ET） model and cumulative forest cover data were used to quantify the changes in annual water yield in response to reforestation in a larg...A simplified water balance model in conjunc- tion with an evapotranspiration （ET） model and cumulative forest cover data were used to quantify the changes in annual water yield in response to reforestation in a large watershed, northeast China. Cumulative forest cover increased by 22 %, leading to a significant decrease in estimated annual water yield. Reforestation increased ET （P = 0.0144）, resulting in a remarkable decrease （P = 0.0001） in estimated annual water yield according to the water balance model. Reforestation increased ET by 33 mm and decreased annual water yield by 38 mm per decade. The effect of reforestation on annual water yield can be quantified using a simplified water balance model in a large watershed, although our reforestation area was small （about 20 %） in relation to the total watershed area.展开更多
Digested effluent of manure (DEM) produced by biogas-plants contains many macro- and micro-nutrients. In an experiment conducted in southern Kyushu (Japan), forage crops cultivated after receiving DEM and chemical fer...Digested effluent of manure (DEM) produced by biogas-plants contains many macro- and micro-nutrients. In an experiment conducted in southern Kyushu (Japan), forage crops cultivated after receiving DEM and chemical fertilizers exhibited similar dry matter yields. From a logistical standpoint, however, DEM in liquid form is difficult to handle and apply due to the low concentration of nutrients. To overcome this shortcoming, we prepared dehydrated DEM (DDEM) by adding DEM to cattle manure without disturbing the manure fermentation process. The objective of this research was to evaluate the effect of DDEM on dry matter yield and nitrogen recovery rate in annual dual-cropping systems (summer crop of maize or sorghum and winter crop of Italian ryegrass) that are typical of the region and to compare these results to commercial cattle manure alone, in combination with chemical fertilizer (CM or CM + CF), or no fertilizer application (NF). In both cropping systems, the DDEM treatment produced similar dry matter yields (2.6 to 3.02 kg·m-2) and apparent nitrogen recovery rates (43% to 53%) as the CM + CF and CM treatments. This suggests that DDEM can potentially replace chemical fertilizers and commercial cattle manure in the region.展开更多
The yield production and energy budget of agroecosystem was carried out at three different climatic regions, i.e., tropical, sub-tropical, and temperate in Garhwal Himalaya, India. The total human population was the h...The yield production and energy budget of agroecosystem was carried out at three different climatic regions, i.e., tropical, sub-tropical, and temperate in Garhwal Himalaya, India. The total human population was the highest （1 140） in tropical region, followed by 464 in temperate region, and 374 in sub-tropical region. Livestock population had also a similar trend with human population in each climatic region, which was 870, 290, and 188 in the tropical, temperate, and sub-tropical regions, respectively, in winter season, the crop production was the highest （2 332 kg hat yr-l） for Triticum aestivum in tropical region followed by 1 716 kg ha^-1 yr^-1 in sub-tropical region, and 1 473 kg ha^-1 yr^-1 in temperate region. The associated crops were Itordeurn vulgate, Brassica caml ＇stris, and Pisum sativa. However, in summer season, the most contributing crop was Oryza sativa, which had also the highest production in tropical region followed by sub-tropical region, and temperate region, i.e., 1 160, 1096, and 1 076 kg ha^-1 yr^-1, respectively. Other growing crops were Elusine coracana, Vigna mugo, Glycine soja, and Echnochlolafrumentaceae. Brassiea rugosa was the only crop grown in tropical region between the period of winter and summer season. The total root production of crops in each climatic region was the highest in tropical region （1 846.2 kg ha^-1 yr^-1）, followed by temperate region （1 841.5 kg ha^-1 yr^-1） and sub-tropical region （1442.5 kg ha^-1 yr^-1）. However, shoot components of crops were 20 241.5, 17 847.0, and 1 188.3 kg ha^-1 yr^-1, which recorded parallel to root in each climatic region. The root and shoot components of weed decreased with increasing altitudes, which were 105.39 and 1150.5 kg ha^-1 yr^-1 in tropical region, 94.55 and 1147.5 kg ha^-1 yr^-1 in sub-tropical region, and 73.33 and 871.5 kg ha^-1 yr^-1 in temperate region for root and shoot, respectively. In the energy inputs, the most contribution was of compost in each climatic region. Among the region, the highest input of compost was in temperate region followed by sub-tropical, and the lowest in temperate region. The fertilizer input was only recorded from tropical region because of its close connection with market and easy accessibility to the farmer compared to subropical and temperate regions. The energy input ranged from 0.39×10^5 to 0.44× 10^5 MJ ha^-1 （human labour）, 0.84× 10^5 to 1.09× 10^5 MJ ha^-1 （bullock labour）, 0.36×10^5 to 0.45×10^5 MJ ha^-1 （seed）, 16.65 × 10^5 to 32.65 ×10^5 MJ ha^-1 （compost）, while output ranged from 8.44 × 10^5 to 11.01 × 10^5 MJ ha^-1 （agronomic yield）, and 14.22× 10^5 to 19.35 ×10^5 MJ ha^-1 （crop-residue）. The total input was the highest in temperate region, followed by subtropical and tropical region, and the highest output was in tropical region and the lowest in sub-tropical region.展开更多
山东北部沿海平原区小麦-玉米周年两吨粮超高产技术创建是中国农业大学作物化控团队和莱州市金海种业在山东省莱州市开展的一项重要农业生产示范项目。通过精选良种、合理密植及水肥一体化等措施,以期实现小麦和玉米的高产高效种植。在2...山东北部沿海平原区小麦-玉米周年两吨粮超高产技术创建是中国农业大学作物化控团队和莱州市金海种业在山东省莱州市开展的一项重要农业生产示范项目。通过精选良种、合理密植及水肥一体化等措施,以期实现小麦和玉米的高产高效种植。在2023年该地块小麦和玉米两季的种植中,现场实测每公顷的总产量达到了31,323.90 kg(折合2088.26 kg mu^(-1))。其中冬小麦由农业农村部组织专家测产打破了黄淮海地区小麦的单产纪录,实际产量高达13,213.35 kg hm^(-2)(折合880.89 kg mu^(-1))。种植品种烟农1212每平方米穗数为692.0,穗粒数为40.1,千粒重为52.55 g,单株产量为4.74 g,收获指数为0.56,水分利用效率为3.24 kg m-3。夏玉米中金玉2513的每平方米穗数为9.1,穗粒数为584.7,千粒重为379.31 g,单株产量为206.25 g,收获指数为0.58,水分利用效率为2.86 kg m^(-3),实际产量为18,110.55 kg hm^(-2)(折合1207.37 kg mu^(-1))。在2024年的重复试验中,小麦-玉米的实际产量继续达到30,997.00 kg hm^(-2)(折合2065.13 kg mu^(-1))。本文旨在总结高产纪录小麦-玉米复种高产田生产过程的主要管理环节和高产群体的主要指标,为山东北部沿海平原区小麦-玉米复种高产提供参考。展开更多
Sediment has been identified as a significant threat to water quality and channel clogging that in turn may lead to river flooding. With the increasing awareness of the impairment from sediment to water bodies in a wa...Sediment has been identified as a significant threat to water quality and channel clogging that in turn may lead to river flooding. With the increasing awareness of the impairment from sediment to water bodies in a watershed, identifying the locations of the major sediment sources and reducing the sediment through management practices will be important for an effective watershed management. The annualized agricultural non-point source pollution(AnnAGNPS) model and newly developed GIS interface for it were applied in a small agricultural watershed, Redrock Creek watershed, Kansas, in this pilot study for exploring the effectiveness of using this model as a management tool. The calibrated model appropriately simulated monthly runoff and sediment yield through the practices in this study and potentially suggested the ways of sediment reduction through evaluating the changes of land use and field operation in the model for the purpose of watershed management.展开更多
Climate variability has become a decisive factor for the crop yields in Sub-Saharan African countries. Inter-annual variability in rainfall has been the key climatic element that determines the success of agriculture ...Climate variability has become a decisive factor for the crop yields in Sub-Saharan African countries. Inter-annual variability in rainfall has been the key climatic element that determines the success of agriculture in this region.From an analysis of recent rainfall conditions in West Africa,FAO(2001) concluded that a long-term change in rainfall has occurred in the semi-arid and sub-humid zones of West Africa.Thus,this study aims at assessing the vulnerability of crop yields to inter-annual variability in rainfall in sub-Saharan African countries taking Nigeria as a case study.A time series of the averaged value of the 12-Month Weighted Anomaly Standardized Precipita-展开更多
The design of a stall-regulated wind turbine to achieve a maximum annual energy output is still a formidable task for engineers. The design could be carried out using an average wind speed together with a standard sta...The design of a stall-regulated wind turbine to achieve a maximum annual energy output is still a formidable task for engineers. The design could be carried out using an average wind speed together with a standard statistical distribution such as a Weibull with k = 2.0. In this study a more elaborated design will be attempted by also considering the statistical bias as a design criterion. The wind data used in this study were collected from three areas of the Lamtakong weather station in Nakhonratchasima Provice, the Khaokoh weather station in Phetchaboon and the Sirindhorn dam weather station in Ubonratchathani, Thailand. The objective is to design a best aerodynamic configurations for the blade (chord, twist and pitch) using the same airfoil as that of NREL Phase VI wind turbine. Such design is carried out at a design wind speed point. Wind turbine blades were optimized for both maximum annual energy production and minimum cost of energy using a method that take into account aerodynamic and structural considerations. The work will be carried out by the program “SuWiTStat” which was developed by the authors and based on BEM Theory (Blade Element Momentum). Another side issue is the credibility of the Weibull statistic in representing the real wind measurement. This study uses a regression analysis to determine this issue.展开更多
Based on grain yield data of China, the vanation features of grain yield in China in recent 40 years and their relationships with the associated factors were analyzed. Results show that the total grain yield increased...Based on grain yield data of China, the vanation features of grain yield in China in recent 40 years and their relationships with the associated factors were analyzed. Results show that the total grain yield increased gradually, and its interannual variation is influenced principally by unit area crop yield (about 70 percent in average). The influences of agricultural technology, social factors and weather conditions on thet area crop yield can be separated because of their unique variation trends and time scales. The influence of agricultural technology is in a smoothly and gradually incremental trend, and the influence of the social factors is oscillated with three waves in recent 40 years, and the influence of weather conditions is fiuctuated sharply from year to year. Their mean effects on the inter-annual variation of unit area crop yield are about 35 to 40 percent, 10 to 15 percent and 50 percent respectively. In the view point of predictions, the effects of weather conditions are much more important.展开更多
文摘The GM(1,1)grey model was used to simulate and divide the harvest years of black-skinned sugarcane yield in Wengyuan County during 2006-2021.Based on the meteorological observation data of Wengyuan County during the same period,the impact of major meteorological disasters such as drought,flood and frost in the growth period of black-skinned sugarcane was analyzed.It is believed that the instability of black-skinned sugarcane yield was affected by comprehensive meteorological factors.It is necessary to master the characteristics of local meteorological disasters,conduct scientific cultivation according to local conditions,and continuously improve the meteorological service level of black-skinned sugarcane cultivation.
基金financially supported by the State Forestry Administration of China(201404201)the Guangxi Natural Science Foundation of China(2012GXNSFBA053140)+2 种基金the Fundamental Research Funds of Guangxi Academy of Sciences(13YJ22ZWS22)the Guangxi Institute of Botany(12001)CFERN&GENE Award Funds on Ecological Paper
文摘A simplified water balance model in conjunc- tion with an evapotranspiration （ET） model and cumulative forest cover data were used to quantify the changes in annual water yield in response to reforestation in a large watershed, northeast China. Cumulative forest cover increased by 22 %, leading to a significant decrease in estimated annual water yield. Reforestation increased ET （P = 0.0144）, resulting in a remarkable decrease （P = 0.0001） in estimated annual water yield according to the water balance model. Reforestation increased ET by 33 mm and decreased annual water yield by 38 mm per decade. The effect of reforestation on annual water yield can be quantified using a simplified water balance model in a large watershed, although our reforestation area was small （about 20 %） in relation to the total watershed area.
文摘Digested effluent of manure (DEM) produced by biogas-plants contains many macro- and micro-nutrients. In an experiment conducted in southern Kyushu (Japan), forage crops cultivated after receiving DEM and chemical fertilizers exhibited similar dry matter yields. From a logistical standpoint, however, DEM in liquid form is difficult to handle and apply due to the low concentration of nutrients. To overcome this shortcoming, we prepared dehydrated DEM (DDEM) by adding DEM to cattle manure without disturbing the manure fermentation process. The objective of this research was to evaluate the effect of DDEM on dry matter yield and nitrogen recovery rate in annual dual-cropping systems (summer crop of maize or sorghum and winter crop of Italian ryegrass) that are typical of the region and to compare these results to commercial cattle manure alone, in combination with chemical fertilizer (CM or CM + CF), or no fertilizer application (NF). In both cropping systems, the DDEM treatment produced similar dry matter yields (2.6 to 3.02 kg·m-2) and apparent nitrogen recovery rates (43% to 53%) as the CM + CF and CM treatments. This suggests that DDEM can potentially replace chemical fertilizers and commercial cattle manure in the region.
文摘The yield production and energy budget of agroecosystem was carried out at three different climatic regions, i.e., tropical, sub-tropical, and temperate in Garhwal Himalaya, India. The total human population was the highest （1 140） in tropical region, followed by 464 in temperate region, and 374 in sub-tropical region. Livestock population had also a similar trend with human population in each climatic region, which was 870, 290, and 188 in the tropical, temperate, and sub-tropical regions, respectively, in winter season, the crop production was the highest （2 332 kg hat yr-l） for Triticum aestivum in tropical region followed by 1 716 kg ha^-1 yr^-1 in sub-tropical region, and 1 473 kg ha^-1 yr^-1 in temperate region. The associated crops were Itordeurn vulgate, Brassica caml ＇stris, and Pisum sativa. However, in summer season, the most contributing crop was Oryza sativa, which had also the highest production in tropical region followed by sub-tropical region, and temperate region, i.e., 1 160, 1096, and 1 076 kg ha^-1 yr^-1, respectively. Other growing crops were Elusine coracana, Vigna mugo, Glycine soja, and Echnochlolafrumentaceae. Brassiea rugosa was the only crop grown in tropical region between the period of winter and summer season. The total root production of crops in each climatic region was the highest in tropical region （1 846.2 kg ha^-1 yr^-1）, followed by temperate region （1 841.5 kg ha^-1 yr^-1） and sub-tropical region （1442.5 kg ha^-1 yr^-1）. However, shoot components of crops were 20 241.5, 17 847.0, and 1 188.3 kg ha^-1 yr^-1, which recorded parallel to root in each climatic region. The root and shoot components of weed decreased with increasing altitudes, which were 105.39 and 1150.5 kg ha^-1 yr^-1 in tropical region, 94.55 and 1147.5 kg ha^-1 yr^-1 in sub-tropical region, and 73.33 and 871.5 kg ha^-1 yr^-1 in temperate region for root and shoot, respectively. In the energy inputs, the most contribution was of compost in each climatic region. Among the region, the highest input of compost was in temperate region followed by sub-tropical, and the lowest in temperate region. The fertilizer input was only recorded from tropical region because of its close connection with market and easy accessibility to the farmer compared to subropical and temperate regions. The energy input ranged from 0.39×10^5 to 0.44× 10^5 MJ ha^-1 （human labour）, 0.84× 10^5 to 1.09× 10^5 MJ ha^-1 （bullock labour）, 0.36×10^5 to 0.45×10^5 MJ ha^-1 （seed）, 16.65 × 10^5 to 32.65 ×10^5 MJ ha^-1 （compost）, while output ranged from 8.44 × 10^5 to 11.01 × 10^5 MJ ha^-1 （agronomic yield）, and 14.22× 10^5 to 19.35 ×10^5 MJ ha^-1 （crop-residue）. The total input was the highest in temperate region, followed by subtropical and tropical region, and the highest output was in tropical region and the lowest in sub-tropical region.
文摘山东北部沿海平原区小麦-玉米周年两吨粮超高产技术创建是中国农业大学作物化控团队和莱州市金海种业在山东省莱州市开展的一项重要农业生产示范项目。通过精选良种、合理密植及水肥一体化等措施,以期实现小麦和玉米的高产高效种植。在2023年该地块小麦和玉米两季的种植中,现场实测每公顷的总产量达到了31,323.90 kg(折合2088.26 kg mu^(-1))。其中冬小麦由农业农村部组织专家测产打破了黄淮海地区小麦的单产纪录,实际产量高达13,213.35 kg hm^(-2)(折合880.89 kg mu^(-1))。种植品种烟农1212每平方米穗数为692.0,穗粒数为40.1,千粒重为52.55 g,单株产量为4.74 g,收获指数为0.56,水分利用效率为3.24 kg m-3。夏玉米中金玉2513的每平方米穗数为9.1,穗粒数为584.7,千粒重为379.31 g,单株产量为206.25 g,收获指数为0.58,水分利用效率为2.86 kg m^(-3),实际产量为18,110.55 kg hm^(-2)(折合1207.37 kg mu^(-1))。在2024年的重复试验中,小麦-玉米的实际产量继续达到30,997.00 kg hm^(-2)(折合2065.13 kg mu^(-1))。本文旨在总结高产纪录小麦-玉米复种高产田生产过程的主要管理环节和高产群体的主要指标,为山东北部沿海平原区小麦-玉米复种高产提供参考。
文摘Sediment has been identified as a significant threat to water quality and channel clogging that in turn may lead to river flooding. With the increasing awareness of the impairment from sediment to water bodies in a watershed, identifying the locations of the major sediment sources and reducing the sediment through management practices will be important for an effective watershed management. The annualized agricultural non-point source pollution(AnnAGNPS) model and newly developed GIS interface for it were applied in a small agricultural watershed, Redrock Creek watershed, Kansas, in this pilot study for exploring the effectiveness of using this model as a management tool. The calibrated model appropriately simulated monthly runoff and sediment yield through the practices in this study and potentially suggested the ways of sediment reduction through evaluating the changes of land use and field operation in the model for the purpose of watershed management.
文摘Climate variability has become a decisive factor for the crop yields in Sub-Saharan African countries. Inter-annual variability in rainfall has been the key climatic element that determines the success of agriculture in this region.From an analysis of recent rainfall conditions in West Africa,FAO(2001) concluded that a long-term change in rainfall has occurred in the semi-arid and sub-humid zones of West Africa.Thus,this study aims at assessing the vulnerability of crop yields to inter-annual variability in rainfall in sub-Saharan African countries taking Nigeria as a case study.A time series of the averaged value of the 12-Month Weighted Anomaly Standardized Precipita-
文摘The design of a stall-regulated wind turbine to achieve a maximum annual energy output is still a formidable task for engineers. The design could be carried out using an average wind speed together with a standard statistical distribution such as a Weibull with k = 2.0. In this study a more elaborated design will be attempted by also considering the statistical bias as a design criterion. The wind data used in this study were collected from three areas of the Lamtakong weather station in Nakhonratchasima Provice, the Khaokoh weather station in Phetchaboon and the Sirindhorn dam weather station in Ubonratchathani, Thailand. The objective is to design a best aerodynamic configurations for the blade (chord, twist and pitch) using the same airfoil as that of NREL Phase VI wind turbine. Such design is carried out at a design wind speed point. Wind turbine blades were optimized for both maximum annual energy production and minimum cost of energy using a method that take into account aerodynamic and structural considerations. The work will be carried out by the program “SuWiTStat” which was developed by the authors and based on BEM Theory (Blade Element Momentum). Another side issue is the credibility of the Weibull statistic in representing the real wind measurement. This study uses a regression analysis to determine this issue.
文摘Based on grain yield data of China, the vanation features of grain yield in China in recent 40 years and their relationships with the associated factors were analyzed. Results show that the total grain yield increased gradually, and its interannual variation is influenced principally by unit area crop yield (about 70 percent in average). The influences of agricultural technology, social factors and weather conditions on thet area crop yield can be separated because of their unique variation trends and time scales. The influence of agricultural technology is in a smoothly and gradually incremental trend, and the influence of the social factors is oscillated with three waves in recent 40 years, and the influence of weather conditions is fiuctuated sharply from year to year. Their mean effects on the inter-annual variation of unit area crop yield are about 35 to 40 percent, 10 to 15 percent and 50 percent respectively. In the view point of predictions, the effects of weather conditions are much more important.
