Cassman Kenneth G, Dobermann Achim, Walters Daniel T
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583-0915, USA.
Ambio. 2002 Mar;31(2):132-40. doi: 10.1579/0044-7447-31.2.132.
The global challenge of meeting increased food demand and protecting environmental quality will be won or lost in cropping systems that produce maize, rice, and wheat. Achieving synchrony between N supply and crop demand without excess or deficiency is the key to optimizing trade-offs amongst yield, profit, and environmental protection in both large-scale systems in developed countries and small-scale systems in developing countries. Setting the research agenda and developing effective policies to meet this challenge requires quantitative understanding of current levels of N-use efficiency and losses in these systems, the biophysical controls on these factors, and the economic returns from adoption of improved management practices. Although advances in basic biology, ecology, and biogeochemistry can provide answers, the magnitude of the scientific challenge should not be underestimated because it becomes increasingly difficult to control the fate of N in cropping systems that must sustain yield increases on the world's limited supply of productive farm land.
满足不断增长的粮食需求并保护环境质量这一全球挑战的成败，将取决于生产玉米、水稻和小麦的种植系统。在发达国家的大规模系统和发展中国家的小规模系统中，实现氮供应与作物需求同步且无过剩或不足，是优化产量、利润和环境保护之间权衡的关键。制定研究议程并制定有效政策以应对这一挑战，需要对这些系统中当前的氮利用效率水平和损失、对这些因素的生物物理控制以及采用改进管理措施的经济回报有定量的了解。尽管基础生物学、生态学和生物地球化学的进展可以提供答案，但不应低估这一科学挑战的规模，因为在世界有限的高产农田供应上必须维持产量增长的种植系统中，控制氮的去向变得越来越困难。
