Irrigation Managemnet For Winter Wheat In China Based On Meta-analysis And Irrigation Evaluation

Winter wheat is one of the main food crops in China.Irrigation system,as an important parameter of farmland irrigation,has important strategic position and far-reaching significance for ensuring food security and achieving sustainable development of low energy consumption agriculture and rural economy.At present,the researches on winter wheat irrigation schedules focus on the field experiments at specific locations and the optimization of irrigation schemes based on crop models.There are abundant data of field irrigation experiments,but the results are different,and there is a lack of systematic comprehensive analysis.Therefore,based on more than 90 literatures published before 2017 on the yield and water use efficiency(WUE)under irrigation conditions of winter wheat in China,this study summarized the suitable irrigation schemes for winter wheat under different climatic conditions in different regions by using Meta-analysis and TOPSIS(technique for order preference by similarity to an ideal solution)methods,and on this basis,designed the database query software of irrigation schemes to provide field irrigation for farmers.It also provides theoretical basis and technical support for the optimization of irrigation system in different regions.The main results are as follows:(1)Compared with no irrigation during growing period,the average incremental yield of winter wheat after irrigation was 39.36%,27.99% in Northwest China,47.55% in North China,85.92% in Central China and 19.59% in East China,and the average relative water use efficiency of winter wheat was respectively 3.41%,6.40%,4.61%,34.66% and-7.82% in different regions.(2)The yield of irrigated winter wheat is affected by irrigation quota,temperature and rainfal.Compared with no irrigation in growth period,the effect size of yield increases with the increasing of irrigation quota,but the increasing trend tends to be steady gradually.The effect size of yield increases with the increase of average temperature and annual average temperature in growing period.(3)Irrigation quota,temperature and rainfall all affect the WUE of irrigated winter wheat in varying degrees.Irrigation quota > 240 mm significantly reduced the WUE of winter wheat.Irrigation significantly increased the WUE of winter wheat when rainfall was less during growth period and the effect size of WUE of irrigated winter wheat increased with the increasing of annual average temperature and growth period average temperature.(4)The results based on Meta-analysis show that the irrigation quotas for high yield in dry,normal and wet years in Northwest China are respectively 315mm、120mm and 70 mm those corresponding to high WUE are 75mm、37.5mm and 210 mm,while those for high yield in dry,normal and wet years in North China are respectively 203.7mm 、 135 mm and75mm,whose corresponding in high WUE are 75mm、75mm 和 180 mm.For dry and wet years in Central China,the irrigation quotas aiming at high yield are 90 mm and 60 mm.But when aiming at high WUE,the corresponding irrigation quotas are equal to 90 mm.The highyield irrigation quotas in dry and normal years are equal to 120 mm in East China,and the corresponding irrigation quotas in high WUE are respectively 102 mm and 120 mm.(5)The evaluation method based on the TOPSIS shows that the irrigation schedule in normal year under the sprinkler irrigation conditions of Yangling in Shaanxi Province is :irrigation quota 80 mm,irrigati ng at jointing stage and flowering stage respectively 40 mm..The drip irrigation schedule of winter wheat in dry years in Jiaozhou land in Shandong Province is as follows: irrigation quota 120 mm,greening stage,jointing stage,fil ing stage and flowering stage are irrigated separately 30 mm.