Date Published: June 29, 2017
Publisher: Public Library of Science
Author(s): Linlin Wang, Shiwen Wang, Wei Chen, Hongbing Li, Xiping Deng, Aimin Zhang.
Improving the efficiency of resource utilization has received increasing research attention in recent years. In this study, we explored the potential physiological mechanisms underlying improved grain yield and water-use efficiency of winter wheat (Triticum aestivum L.) following organic fertilizer application. Two wheat cultivars, ChangHan58 (CH58) and XiNong9871 (XN9871), were grown under the same nitrogen (N) fertilizer rate (urea-N, CK; and manure plus urea-N, M) and under two watering regimes (WW, well-watered; and WS, water stress) imposed after anthesis. The M fertilizer treatment had a higher Pn and lower gs and Tr than CK under both water conditions, in particular, it significantly increased WRC and Ψw, and decreased EWLR and MDA under WS. Also, the M treatment increased post-anthesis N uptake by 81.4 and 16.4% under WS and WW, thus increasing post-anthesis photosynthetic capacity and delaying leaf senescence. Consequently, the M treatment increased post-anthesis DM accumulation under WS and WW by 51.5 and 29.6%, WUEB by 44.5 and 50.9%, grain number per plant by 11.5 and 12.2% and 1000-grain weight by 7.3 and 3.6%, respectively, compared with CK. The grain yield under M treatment increased by 23 and 15%, and water use efficiency (WUEg) by 25 and 23%, respectively. The increased WUE under organic fertilizer treatment was due to elevated photosynthesis and decreased Tr and gs. Our results suggest that the organic fertilizer treatment enabled plants to use water more efficiently under drought stress.
Water shortage is the main abiotic factor limiting plant production on the Loess Plateau of China, with crop growth and economic yield being severely affected. Although the vegetative growth of winter wheat in the area occurs during relatively good soil moisture conditions, the grain filling is often impaired by terminal water stress. In most cases, crops may not be able to use nitrogen (N) efficiently if water is a limiting factor for growth and production ; thus, N content is also a limiting factor for crop production in dryland cropping systems . To achieve higher crop yield, the application of synthetic N fertilizers has markedly increased in recent years . The increasing use of inorganic fertilizer and neglect of organic fertilizer as a valuable source of nutrients have contributed to nutrient imbalance, low fertilizer use efficiency , deterioration in soil quality [5–7], nitrate leaching, and nitrous oxide emissions, soil acidification  and carbon (C) loss , which seriously limit crop productivity. Therefore, the effective use of limited water resources and chemical fertilizer to achieve high yield is a major objective of modern agriculture in the Loess Plateau, and will have a considerable impact at local and regional scales.