Climatic changes in yield index and soil water deficit trends in China

Long-term trends of the combined effects of evapotranspiration and precipitation effect surface hydrology and soil water and consequently natural and agricultural ecosystems. This paper analyses yield index and soil water deficit time series derived from water balance calculations for multiple cropping systems with FAO methodology. The analysis shows that yield index values have increased and soil water deficits have consequently decreased over much of China during 1954–1993. The likely parameters contributing to this trend are precipitation changes north of 35°N and maximum evapotranspiration as well as available soil water trends south of this line. Increasing the assumed maximum soil water storage did not result in substantially different results. While this analysis indicates that regional climatic change appears to have had a beneficial effect for several regions in China, predictions from combined global climate model climate change experiments anticipate decreasing yields due to decreased water availability by 2050 in the same regions.