Integrated soil–crop system management for food security

Abstract

China and other rapidly developing economies face the dual challenge of substantially increasing yields of cereal grains while at the same time reducing the very substantial environmental impacts of intensive agriculture. We used a model-driven integrated soil-crop system management approach to develop a maize production system that achieved mean maize yields of 13.0 t ha −1 on 66 on-farm experimental plots-nearly twice the yield of current farmers' practices-with no increase in N fertilizer use. Such integrated soil-crop system management systems represent a priority for agricultural research and implementation, especially in rapidly growing economies.environmental integrity | nutrient use efficiency | crop yield | nitrogen fertilization | smallholder farm

Scope for improved eco-efficiency varies among diverse cropping systems

“…In this survey, the Chinese farmers achieved a reasonable platform in technical efficiency, reflecting both a baseline in the application of available technologies and the advantages of irrigated systems. However, farmer-implemented on-farm demonstrations achieved an average technical efficiency of 0.85, demonstrating what can be realistically achieved when identified constraints are addressed (12).…”

“…Many of Australia's commercial wheat farmers achieve high technical efficiency and have little prospect of returns from increasing their N inputs; new technologies and practices are essential to increasing their production without debilitating risks. Many Chinese farmers can reduce N inputs without sacrificing production through more efficient use of their current fertilizer resources; their environment will benefit as well (12). Most African farmers have the opportunity for significant production increases by both improving their technical efficiency and increasing their N inputs, but doing so will require improved management expertise and institutional support in dealing with the higher risks from investing in increased inputs (14,23).…”

“…None of the systems surveyed here come close to that value, and the rainfed systems never will (without irrigation); average Y p values were 61% for the Chinese wheat-maize systems, 14% for maize in Zimbabwe, and 40% for wheat in Australia (Table 1). That said, the irrigated systems in China should be able to reach 80% or more of Y p , and can do so with the added benefits of reducing N losses to the environment (12). With average wheat yields already at 90% of Y w , Australian rainfed agriculture will not contribute significantly to future food demands without technological breakthroughs.…”

“…However, N unused by crops can be lost as emissions of potent greenhouse gases, including nitrous oxide (N 2 O), or from the root zone, leading to acidification in soils and nitrate contamination of water resources (11). Consequently, improved management of N fertilizers, leading to zero or low-intensity N emissions, serves as a key indicator of improved production and environmental performance of cropping systems (12)(13)(14)(15).…”

Solutions for a cultivated planet

“…Targeting particular 'hotspots' of low efficiency, measured as the disproportionate use of water and nutrient inputs relative to production, could significantly reduce the environmental problems of intensive agriculture. Furthermore, agroecological innovations in crop and soil management 1,67 show great promise for improving the resource efficiency of agriculture, maintaining the benefits of intensive agriculture while greatly reducing harm to the environment.…”