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ABSTRACT
Water resources in the North China Plain (NCP) are limited, so it's in urgent need to optimize deficit by irrigation for sustainable winter wheat production in this area. Winter wheat grain yield (GY), contribution of dry matter (DM) remobilization to GY (CDMRG), and water use efficiency (WUE) were investigated in NCP. Compared with non-irrigation treatment, irrigated with 60 mm each at the winter wheat jointing stage (JS) and heading stage (HS) achieved reasonable winter wheat GY and WUE. Compared with irrigation with 120 mm only at JS and irrigation with 40 mm each at JS, HS, and milking stage (MS) of winter wheat, irrigation with 60 mm each at JS and HS provided the highest CDMRG, which resulted to the highest GY and WUE; this result was mainly due to a significant increase of the spike numbers (SN) per m2. The results suggest that in the NCP, in order to achieve reasonable GY and WUE, winter wheat should be irrigated with 60 mm each at JS and HS.
Keywords: Aboveground dry matter; Soil water content; Evapotranspiration; Precipitation; Growing season
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INTRODUCTION
The NCP, covers an area of more than 1.5 million hectare. In this region, winter common wheat is the most important cultivated crop, and produces about 50% of the total winter wheat GY (Tian et al., 2013). Many results indicated that the water requirement over the growing season of winter wheat was more than 400 mm (Bian et al., 2016; Zhao et al., 2013; Zhou et al., 2011); however, during the growing season of winter wheat, precipitation ranges from 100 to 180 mm. Therefore, water is the most important limiting factor for the production of winter wheat.
In order to increase winter wheat GY in the NCP, additional irrigation is required. For the shortage of surface water, groundwater has become the most important source of irrigation water (Sun et al., 2010). In recent years, 70% of irrigation water is used for winter wheat (Li et al., 2005). With the increase of winter wheat cultivated land, groundwater levels are persistently declining, and resulting in serious environmental problems, it has already been the widest funnel-shaped zone of groundwater in the world (Guo et al., 2010). Current limitation of...