| Availability of water and fertilizer is major constraint for wheat production in many semiarid regions of the world.Increasing water and fertilizer use efficiency is important for some semiarid regions,such as the southeast of the Loess Plateau.Varieties and sowing methods of water and fertilizer efficient use and their sutable nitrogen and phosphorus exhibits greater potential in yield production.Therefore,field experiments were conducted in experiment sites(Wenxi,Hongdong and Taigu)of Shanxi agricultural university in the southeast of the Loess Plateau.Selecting six varieties to compare the differences of wheat yield and water use efficiency in Wenxi and Hongdong to determine the efficient utilization varieties.Selecting four sowing methods to compare the differences of wheat yield and water and fertilizer use efficiency to determine the efficient use sowing method in Wenxi,Hongdong and Taigu.Effects of three sowing methods and different nitrogen rates on soil water,plant nitrogen uptake,yield and protein formation to determine the optimal planting mode.The main results were as follows:1.Selection of winter wheat varieties with efficient utilization of water and fertilizer.Compared with irrigated wheat varieties,Shannon 29 revealed the highest soil water consumption,grain yield and water use efficiency by raising ear number and 1000-grain weight in wenxi.Shannon 20 revealed the highest soil water consumption,grain yield and water use efficiency by raising ear numbers and the grain numbers per spike in hongtong.Compared with dryland wheat varieties,both higher grain yield and water use efficiency and stable varieties were Jinmai92 and Yunhan 20410,the higher spike number and grain number per spike,improved the grain yield and water use efficiency.Vatieties of more precipitation were Luohan 6,Luohan9 and Luohan 11,the higher spike number and 1000-grain weight,improved the grain yield and water use efficiency.2.Comparative study on the planting method of winter wheat with efficient utilization of water and fertilizer.The highest yield was wide space sowing(WSS),the lowest yield was Drilling sowing(DS).Comparing with Drilling sowing(DS),WSS promoted soil water consumption,wheat growth,spike froming,and improved spike number and yield of more 15%,WUE of 14%.Mulch sowing compared with drilling sowing promoted wheat growth,increased soil water consumption and effective spike number,and improved spike number of 8%,grain number per ear of 26%,and grain yield of 19%,WUE of12%,nitrogen absorption efficiency of 17%and nitrogen production of 31%.3.The optimum nitrogen application of winter wheat with high efficiency of water fertilizer.Effect of different sowing methods combined with different N rates on wheat yield formation results showed that,WSS with N 240 kg·hm-2,Furrow sowing(FS)and DS with 210 kg·hm-2 increased the winter wheat leaf area index,promoted the effective panicles formation,increased the ear numbers and grain number per ear,also improved photosynthetic rate,transpiration rate and stomatal conductance of flag leaf,decreased intercellular CO2 concentration at filling stage,eventually significantly improved the yield,especially WSS with N 240 kg·hm-2,ear number largely contributed to grain yield.Effect of plastic mulch combined with different N rates on wheat yield formation results showed that,Humid year combined with high nitrogen at 225 kg·hm-2,normal year and dry year under the condition of mulching during the fallow period combined with middle nitrogen at 150 kg·hm-2 could increase ear number by 11.3%-22.4%and yield by 23%to 23%.Effect of different sowing methods combined with different N rates on water use results showed that,WSS with N 240 kg·hm-2,Furrow sowing(FS)and DS with 210 kg·hm-2 promoted soil water consumption during growth stage,especially soil water of 100-200 cm soil depth from anthesis to maturity,promoted to increase grain yield.But water use efficiency showed that WSS with N 240 kg·hm-2 was the best in Wenxi and Hongdong.Effect of plastic mulch combined with different N rates on wheat yield formation results showed that,Spatio-temporal dynamics in the soil water storage of 0-300 cm depth exhibited a downward movement with crop development.Approximately half of soil water consumption from flowering to maturity was derived from the 200-300 cm soil layers.Hunid year combined with high nitrogen at 225 kg·hm-2,normal year and dry year under the condition of mulching during the fallow period combined with middle nitrogen at 150 kg·hm-2 could reduce soil water consumption before the jointing stage,leading to more soil water available for grain yield production,improved water use efficiency.Effect of different sowing methods combined with different N rates on plants nitrogen uptake and translocation results showed that,WSS with N 240 kg·hm-2,Furrow sowing(FS)with N 210 kg·hm-2 promoted plant nitrogen uptake during growth stage,WSS with N 240 kg·hm-2 also promoted post-anthesis N uptake to grain,but nitrogen use efficiency were lower.But DS with N 210 kg·hm-2 at wheat early stage,with N 240 kg·hm-2(Hongdong)or 270 kg.hm-2(Wenxi)at wheat early stage facilited plant nitrogen uptade,but nitrogen use efficiency was also lower.The results indicated that Supplementary nitrogen fertilizer was necessary under DS at wheat late stage.Effect of plastic mulch combined with different N rates on plants nitrogen uptake and translocation results showed that,humid year combined with high nitrogen at 225 kg·hm-2,normal year combined with middle nitrogen at 150 kg·hm-2 could facilited nitrogen uptake at middle and late stages,and nitrogen translocation,especially leaf and spike.Dry year under the condition of mulching during the fallow period combined with middle nitrogen at 150 kg·hm-2 could facilited nitrogen uptake at middle and late stages,and nitrogen translocation,especially stem and spike.Dry year under the condition of no mulching during the fallow period combined with middle nitrogen at 75 kg·hm-2 could facilited nitrogen uptake at middle stage.Effect of different sowing methods combin ed with different N rates on grain protein content results showed that,WSS with N 270 kg·hm-2,FS and DS with N 210 kg·hm-2 achieved the highest grain protein,the reason was that higher grain yield at WSS with N 270 kg·hm-2,FS and DS with N 210 kg·hm-2 diluted grain protein content,and achieved higher protein by increasing N 30 kg·hm-2.Effect of plastic mulch combined with different N rates on grain protein content(GPC)results showed that,humid year under the condition of mulching during the fallow period combined with high nitrogen at 225 kg·hm-2,increased grain yield,but GPC reduced by 5.9%.Normal year under the condition of mulching during the fallow period combined with middle nitrogen at 150 kg·hm-2 increased grain yield,but GPC reduced by 3.9%.Dry year under the condition of mulching during the fallow period combined with middle nitrogen at 150 kg·hm-2 increased grain yield,but GPC did not reduce.If the higher GPC is required such as in the wet season,the agronomic or genetic approach such as application of foliar N late in the season is required to improve higher post-anthesis N uptake,or growing cultivars with high GPC.4.Optimal phosphorus application of winter wheat with efficient utilization of water and fertilizer.The results also showed that phosphorus levels affected dry-land wheat soil water storage of 0-300 cm layer,and was decreased under the long-term phosphorus(4 year positioning test),and the difference was significant with other treatments in the fourth year.In the third and fourth year,soil moisture is not balanced,annual soil water consumption was different between phosphorus of 150 kg·hm-2 and 0 kg·hm-2.In addition,the F value test showed that years had the greatest influence on yield and water use efficiency,the yield increase effect of sub-soiling was higher than that of phosphorus fertilizer,but each additional 1kg@hm-2 phosphorus can also increase the yield by 2 to 13 kgh@hm-2.Under the sowing water storage of 0-300 cm with more than 550 mm combined with the phosphorus amount of 75 kg·hm-2,or below 550 mm combined with the phosphorUs adount of 150 kg·hm-2,made the spike number,yield and WUE higher. |
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