China has to raise agricultural productivity in its limited and shrinking farmland to guarantee food security for its huge and ever-growing population. Sustainable soil nutrient management is of paramount importance t...China has to raise agricultural productivity in its limited and shrinking farmland to guarantee food security for its huge and ever-growing population. Sustainable soil nutrient management is of paramount importance to the world's most populous country. Critical challenges the country is facing in sustaining soil fertility and in alleviating the hazardous impact of intensive fertilizer use are discussed in this paper. It is emphatically pointed out that national strategies as well as area-specific action plans with respect to scientific nutrient management are urgently needed to balance productivity and sustainability in the future. Relevant proposals for addressing those challenges are also presented.展开更多
Global nitrogen (N) budgets for intensive agricultural systems were compiled for a 0.5 by 0.5 degree resolution. These budgets include N inputs (N fertilizer, animal manure, biological N fixation and atmospheric N dep...Global nitrogen (N) budgets for intensive agricultural systems were compiled for a 0.5 by 0.5 degree resolution. These budgets include N inputs (N fertilizer, animal manure, biological N fixation and atmospheric N deposition) and outputs (N removal from the field in harvested crops and grass and grass consumption by grazing animals, ammonia volatilization,denitrification and leaching). Data for the historical years 1970 and 1995 and a projection for 2030 were used to study changes in the recovery of N and the different loss terms for intensive agricultural systems. The results indicate that the overall system N recovery and fertilizer use efficiency slowly increased in the industrialized countries between 1970 and 1995, the values for developing countries have decreased in the same period. For the coming three decades our results indicate a rapid increase in both the industrialized and developing countries. High values of ＞ 80% for fertilizer use efficiency may be related to surface N balance deficits, implying a depletion of soil N and loss of soil fertility. The projected intensification in most developing countries will cause a gradual shift from deficits to surpluses in the coming decades.The projected fast growth of crop and livestock production, and intensification and associated increase in fertilizer inputs will cause a major increase in the surface N balance surplus in the coming three decades. This implies increasing losses of N compounds to air (ammonia, nitrous oxide and nitric oxide), and groundwater and surface water (nitrate).展开更多
The study was undertaken to assess the inorganic fertilizer production and consumption, export and import trends in Nigeria, assess the effect of food legume technology on farmers＇output, income, household inventorie...The study was undertaken to assess the inorganic fertilizer production and consumption, export and import trends in Nigeria, assess the effect of food legume technology on farmers＇output, income, household inventories and inorganic fertilizer usage. Multi-stage sampling technique procedure was adopted in obtaining 300 respondents. Primary and secondary data were used. Simple descriptive statistics, t-test and correlation were used to analyse the data. Both the trend analysis result and test of mean differences showed a wide gap. The result revealed a significant increase in the yields of maize, millet, cocoyam, sweet potato, okro, tomato and overall aggregate crop yield of farmers after the adoption of the food legume technology （t = 2.78, 2.23, 3.70, 3.30, 2.20, 3.5 and 2.297; P 〈 0.05）, hence improves food security. Similarly, the result revealed significant positive change in terms of farmers＇ownership of house, increase in the number of rooms, improvement in water source, possession of radio, television/tape recorders and cell phone. Major constraints to production as revealed by the study include pests and diseases, low soil fertility, inadequate finance, storage problem and poor market for products. The study recommends adequate and regular supply of food legume production inputs to farmers and intensive control of pests and diseases.展开更多
基金Project supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Nos. KZCX3-SW-417 and KZCX2-413).
文摘China has to raise agricultural productivity in its limited and shrinking farmland to guarantee food security for its huge and ever-growing population. Sustainable soil nutrient management is of paramount importance to the world's most populous country. Critical challenges the country is facing in sustaining soil fertility and in alleviating the hazardous impact of intensive fertilizer use are discussed in this paper. It is emphatically pointed out that national strategies as well as area-specific action plans with respect to scientific nutrient management are urgently needed to balance productivity and sustainability in the future. Relevant proposals for addressing those challenges are also presented.
基金Project supported by the Netherlands Environmental Assessment Agency, National Institute for Public Health and the Environment (No. S/550005/01/DD) the Canadian International Development Agency, Canada and the Chinese Academy of Sciences, China (No.KZCX2-413)
文摘Global nitrogen (N) budgets for intensive agricultural systems were compiled for a 0.5 by 0.5 degree resolution. These budgets include N inputs (N fertilizer, animal manure, biological N fixation and atmospheric N deposition) and outputs (N removal from the field in harvested crops and grass and grass consumption by grazing animals, ammonia volatilization,denitrification and leaching). Data for the historical years 1970 and 1995 and a projection for 2030 were used to study changes in the recovery of N and the different loss terms for intensive agricultural systems. The results indicate that the overall system N recovery and fertilizer use efficiency slowly increased in the industrialized countries between 1970 and 1995, the values for developing countries have decreased in the same period. For the coming three decades our results indicate a rapid increase in both the industrialized and developing countries. High values of ＞ 80% for fertilizer use efficiency may be related to surface N balance deficits, implying a depletion of soil N and loss of soil fertility. The projected intensification in most developing countries will cause a gradual shift from deficits to surpluses in the coming decades.The projected fast growth of crop and livestock production, and intensification and associated increase in fertilizer inputs will cause a major increase in the surface N balance surplus in the coming three decades. This implies increasing losses of N compounds to air (ammonia, nitrous oxide and nitric oxide), and groundwater and surface water (nitrate).
文摘The study was undertaken to assess the inorganic fertilizer production and consumption, export and import trends in Nigeria, assess the effect of food legume technology on farmers＇output, income, household inventories and inorganic fertilizer usage. Multi-stage sampling technique procedure was adopted in obtaining 300 respondents. Primary and secondary data were used. Simple descriptive statistics, t-test and correlation were used to analyse the data. Both the trend analysis result and test of mean differences showed a wide gap. The result revealed a significant increase in the yields of maize, millet, cocoyam, sweet potato, okro, tomato and overall aggregate crop yield of farmers after the adoption of the food legume technology （t = 2.78, 2.23, 3.70, 3.30, 2.20, 3.5 and 2.297; P 〈 0.05）, hence improves food security. Similarly, the result revealed significant positive change in terms of farmers＇ownership of house, increase in the number of rooms, improvement in water source, possession of radio, television/tape recorders and cell phone. Major constraints to production as revealed by the study include pests and diseases, low soil fertility, inadequate finance, storage problem and poor market for products. The study recommends adequate and regular supply of food legume production inputs to farmers and intensive control of pests and diseases.
