Scope for improved eco-efficiency varies among diverse cropping systems

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 110; no. 21; pp. 8381 - 8386
• Main Authors: Carberry, Peter S., Liang, Wei-li, Twomlow, Stephen, Holzworth, Dean P., Dimes, John P., McClelland, Tim, Huth, Neil I., Chen, Fu, Hochman, Zvi, Keating, Brian A.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 21.05.2013; National Acad Sciences
• Subjects: AGRICULTURAL INNOVATION TO PROTECT THE ENVIRONMENT SPECIAL FEATURE; Agricultural production; Agriculture - economics; Agriculture - methods; Australia; Biological Sciences; Crop economics; Crop management; Crop production; Crop science; Cropping systems; Crops; Crops, Agricultural - economics; Crops, Agricultural - growth & development; Ecosystem; Farmers; Fertilizers - economics; Food crops; Food supply; Food Supply - economics; Food Supply - methods; Grains; International comparisons; Nitrous Oxide; Rainfed farming; Risk assessment; Sustainable agriculture; Australia; Zimbabwe; China; APSIM; nitrogen fertilizer; yield gap; greenhouse gas; potential yield
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1208050110

Global food security requires eco-efficient agriculture to produce the required food and fiber products concomitant with ecologically efficient use of resources. This eco-efficiency concept is used to diagnose the state of agricultural production in China (irrigated wheat–maize double-cropping systems), Zimbabwe (rainfed maize systems), and Australia (rainfed wheat systems). More than 3,000 surveyed crop yields in these three countries were compared against simulated grain yields at farmer-specified levels of nitrogen (N) input. Many Australian commercial wheat farmers are both close to existing production frontiers and gain little prospective return from increasing their N input. Significant losses of N from their systems, either as nitrous oxide emissions or as nitrate leached from the soil profile, are infrequent and at low intensities relative to their level of grain production. These Australian farmers operate close to eco-efficient frontiers in regard to N, and so innovations in technologies and practices are essential to increasing their production without added economic or environmental risks. In contrast, many Chinese farmers can reduce N input without sacrificing production through more efficient use of their fertilizer input. In fact, there are real prospects for the double-cropping systems on the North China Plain to achieve both production increases and reduced environmental risks. Zimbabwean farmers have the opportunity for significant production increases by both improving their technical efficiency and increasing their level of input; however, doing so will require improved management expertise and greater access to institutional support for addressing the higher risks. This paper shows that pathways for achieving improved eco-efficiency will differ among diverse cropping systems.