Producing more grain with lower environmental costs

In an experiment across China to test integrated soil–crop system management for rice, wheat and maize against current practice, improvements in grain yield are equivalent to high-input techniques, but nutrient use, nutrient loss and greenhouse gas emissions are lower than current practice. Integrated soil–crop system management is a technique that aims to maximize yield and minimize environmental impact by adapting cropping systems to local conditions through optimal nutrient application, seasonal timing and the use of the best crop varieties. Fusuo Zhang and colleagues report the results of a China-wide test of this technique for the three main cereal crops — rice, wheat and maize. In comparisons with current practice and high input techniques, the authors find that the integrated system achieves yield improvements equivalent to high input techniques but with lower nutrient use, nutrient loss and greenhouse gas emissions than those found with the current practice. Agriculture faces great challenges to ensure global food security by increasing yields while reducing environmental costs1,2. Here we address this challenge by conducting a total of 153 site-year field experiments covering the main agro-ecological areas for rice, wheat and maize production in China. A set of integrated soil–crop system management practices based on a modern understanding of crop ecophysiology and soil biogeochemistry increases average yields for rice, wheat and maize from 7.2 million grams per hectare (Mg ha−1), 7.2 Mg ha−1 and 10.5 Mg ha−1 to 8.5 Mg ha−1, 8.9 Mg ha−1 and 14.2 Mg ha−1, respectively, without any increase in nitrogen fertilizer. Model simulation and life-cycle assessment3 show that reactive nitrogen losses and greenhouse gas emissions are reduced substantially by integrated soil–crop system management. If farmers in China could achieve average grain yields equivalent to 80% of this treatment by 2030, over the same planting area as in 2012, total production of rice, wheat and maize in China would be more than enough to meet the demand for direct human consumption and a substantially increased demand for animal feed, while decreasing the environmental costs of intensive agriculture.