水保所知识产出(1956---)知识库

Water and nitrogen (N) inputs are essential for increasing crop yields, but overuse inevitably causes substantial
nitrate leaching and the subsequent contamination of groundwater. Water and N use in wheat production in
China is relatively inefficient, so a synthesis of data for the effects of water and N inputs on wheat yield, water-
use efficiency (WUE) and nitrogen-use efficiency (NUE) is necessary. We conducted a meta-analysis based on
4162 yield, 4158 WUE and 3694 NUE observations from 332 peer-reviewed publications to quantify the effects
of water and N inputs on wheat yield, WUE and NUE and to clarify the potentials for saving water and N for
wheat production in China. The positive effects of water or N input on all variables decreased when the optimum
levels of input were exceeded. Actual yield, WUE and NUE were 29.8, 47.2 and 41.8% significantly lower,
respectively, than those potentially attainable. Results differed greatly among regions due to differences in
management and climate. The differences between actual and attainable yield, WUE and NUE were highest in the
northwestern region and lowest in the north-central region. The difference in WUE was largest in the lower and
middle reaches of the Yangtze River. The overall water- and N-saving potentials for wheat production across
China were 22.4 and 26.0%, respectively. Yield was highest at a plant density of 180 plants m −2 . The effects of
the water and N inputs were more pronounced in areas with silty soil and high levels of soil organic carbon.
Yield, WUE and NUE were negatively correlated with mean seasonal temperature, so suitable measures should be
taken to control temperatures <15 ◦ C. This analysis provides scientific guidance for improving the use effi-
ciencies of resources, reducing environmental pollution, advancing China’s food security and improving yield
stability.