Because of serious water shortage and excessive nitrogen (N) applications in Hebei province,the effects of limited irrigation and reduced nitrogen on population dynamics and yield formation in high-yielding field have been studied to provide technical support for sustainable production,high yield and high water-nitrogen use efficiency of winter wheat.Field experiments were carried out during growing seasons in 2013-2014 and 2014-2015,at Gaocheng county in Hebei province,with a winter wheat variety Shimai 18 as material.In 2013-2014,single-factor experiment of limited water with two irrigation ways was designed,including water limited treatment(WL: irrigation of 45 mm at jointing stage,30 mm at anthesis stage,and 30 mm at grain filling stage) and water saving treatment(WS:irrigation of 60 mm at jointing stage,and 60 mm at anthesis stage).In 2014-2015,a split plot experiment with two factors was conducted including three water limited treatments (W1,W2,W3: total irrigation amount 67.5 mm),and one water saving treatment as control(WCK,irrigation 67.5 mm at jointing stage,and 67.5 mm at anthesis stage),and three nitrogen fertilization levels were 120 kg·hm-2,180 kg·hm-2 and 240 kg·hm-2.The results showed that there were not significant difference in leaf area index,light energy interception rate,biological yield,spike number,and grain number per spike between WL and WS in 2013-2014.The 1 000-grain weight of WL increased significantly; the grain yield was 10 081.08 kg·hm-2;and the water use efficiency was 27.98 kg·hm-2·mm-1.In 2014-2015,there was not significant differences in leaf area index and light energy interception rate between W3 (50% reduction in irrigation amount) and WCK.The spike number and grain number of W3 were decreased,but the 1 000-grain weight was increased significantly.The grain yield of W3 was 8 903.70 kg·hm-2,which was 7.95% lower than that of WCK; meanwhile,the biological yield was 7.15% lower than that of WCK.However, the water use efficiency and irrigation use efficiency of W3 were increased by 9.28% and 84.10%,respectively; and this did not increase the consumption of soil water storage in 0-140 cm and 0-200 cm layers.Therefore,the best water limited irrigation model was W3,ensuring high yield and high efficiency under this experiment condition.There was not significant difference in all indices among three nitrogen application treatments.Above all,the optimal combination was the irrigation model(irrigation 37.5 mm at jointing stage,15 mm at anthesis stage,and 15 mm at grain filling stage) with 120 kg·hm-2 N application during the whole wheat growth period. |