Abstract: 【Objective】The objective of the experiment is to study the effects of supplemental irrigation with micro-sprinkling hoses on flag leaves senescence, photosynthetic rate, grain filling rate, grain yield and water use efficiency in winter wheat. 【Method】 Field experiments were carried out in 2011-2013 growth seasons, using high-yield wheat cultivar Jimai 22. Three irrigation treatments were arranged with no irrigation during the whole growth stage (W0), supplemental irrigation with micro-sprinkling hoses (W1), traditional border irrigation (W2), to explore the changes of winter wheat under different treatments in leaf water potential, activities of superoxide dismutase (SOD) and catalase (CAT), chlorophyll fluorescence parameters, canopy apparent photosynthetic rate, grain filling rate, and so on. The irrigation stage in W1 was the same as that in W2. they were all irrigated once at jointing stage and anthesis stage respectively. W1 was irrigated with the micro-sprinkling hoses special for wheat (ZL201220356553.7). The soil water content was measured before irrigation. The target relative soil moisture content in the 0–140 cm soil layer after supplemental irrigation at jointing was set as 70% of field water capacity in 2011-2012 and 2012-2013. The target relative soil moisture content in the 0–140 cm soil layer after supplemental irrigation at anthesis was set as 70% and 65% of field water capacity in 2011-2012 and 2012-2013, respectively. The amount of the supplemental irrigation was calculated according to the irrigation quota formula. W2 was irrigated by the traditional border irrigation method. The inflow cutoff was set as 90% of border length, namely, stopping irrigation when the water reached 90% of the border length. The amount of irrigation was measured by water meter. W1 was the same as W2 in the specifications of experiment plot. In each experimental plot, the border width (the vertical distance between the center of two adjacent border ridges) was 2 m; the border ridge width was 0.4 m; the border length was 60 m and the plot area was 120 m². A 1.0 m wide unirrigated zone was maintained between adjacent plots to minimize the effects of adjacent treatments. Eight rows of winter wheat were planted in each experimental plot with row spacing of 22.9 cm. The micro-sprinkling hose was laid between the fourth and the fifth rows of wheat. A pressure-regulated valve and a flow-meter were installed at the head of each micro-sprinkling irrigation hose. The working pressure of each micro-sprinkling irrigation hose was 0.02 MPa. The irrigation water was pumped from well and then was transported to the inlet of micro-sprinkling irrigation hose or border through the PVC belt. The discharge per unit width of border irrigation was 4.6-5.2 L·m^-1·s^-1.【Result】During the two growth seasons, the supplemental irrigation amounts of W1 were 21.3-96.0 mm at jointing and 29.0-38.5 mm at anthesis. The irrigation water distribution uniformity of W1 reached 82.7%-97.0% after irrigation, not lower than that of the border irrigation with inflow cutoff designed as 90% (W2). The total irrigation amount of W1 reduced by 33.2-70.8 mm, saving 21.0%-54.2% of irrigation water, compared to that of W2. In contrast, there was no significant difference between W1 and W2 in the flag leaf water potential, the activities of SOD and CAT, the content of methane dicarboxylic aldehyde, the flag leaf maximum photochemical efficiency, actual photochemical efficiency, canopy apparent photosynthetic rate, grain filling rate, and grain yield. The water use efficiency of W1 increased by 2.1-2.9 kg·hm^-2·mm^-1 and reached 21.6-23.2 kg·hm^-2·mm^-1. 【Conclusion】 The irrigation amount applied at jointing and anthesis can be adjusted according to the precipitation and soil water content before irrigation by supplemental irrigation with micro-sprinkling hoses, to moderately supply the physiological water requirement of winter wheat for high-yield, and the irrigation water also can be uniformly and accurately sprayed into the field. This technology can excavate greater potential of winter wheat for water-saving.

Key words: wheat, micro-sprinkling hoses, supplemental irrigation, border irrigation, flag leaf senescence, photosynthetic characteristics, yield, water use efficiency