A review of agricultural water-saving research at Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences over the last 30 years

Farmland water-saving research was conducted since the establishment of Luancheng Agro-Ecosystem Experimental Station, Chinese Academy of Sciences (simplified as Luancheng Station). In 1980s, the research was concentrating on optimizing irrigation scheduling to reduce irrigation application for practical use. During that period, farmers usually irrigated winter wheat 7 to 10 times per season. By application an optimized irrigation scheduling, irrigation number was reduced to 5 per season without penalties to yield. In 1990s, the research was changed to fundamental studies of water movement in field. Water transfer and regulation mechanisms in soil-plant-atmosphere continuum were the research focuses during that period, resulting improved understanding of the principles and potential in water-saving. Extensive root sampling was carried out to study the pattern of root growth and soil water utilization. Root distribution down the soil profile was then modified to allow the crop to use soil water more efficiently. Evapotranspiration (ET) and soil evaporation were determined from long term data for different growing stages of winter wheat and summer maize to provide basis for crop-water relation studies. The results showed that seasonal soil water evaporation (measured by micro-lysimeters) accounted for 20%~30% of seasonal ET that reduced soil evaporation could contribute significantly to in-field water-saving. With the intensifying in water shortage in this area, research focuses for the last ten years were on physiological and ecological bases of deficit irrigation. The effects of water deficit on crop growth, water use, yield and water use efficiency (WUE) of winter wheat were studied. The results established that grain production could increase even though irrigation applications were reduced by using a Regulated Deficit Irrigation strategy. The contribution of cultivar improvement on grain production, crop water use and WUE of winter wheat from 1970s to the present time was studied and the results provided guideline for selecting better cultivars for yield and WUE. Combining the technologies and experience of the last 30 years, integrated water-saving models were developed and extended for sustainable groundwater use. In future, water-saving research will still be one of the important research topics at Luancheng Station. Interdisciplinary research that combines breeding, nutrient, cultivation and water will improve crop yield and resource use efficiency.