Effect Of Agronomic Practices On Water Use Efficiency Of Winter Wheat In Rainfed Dryland Of Loess Plateau

The imbalance between water supply and demand leads to water shortage,which has become one of the most pressing problems in the world.For the agriculture sector especially in the rainfed region,water is a more valuable resource.The Loess Plateau is one of the main areas of wheat production in China.In this region,the groundwater level is very deep and it is impossible to be used for irrigation in agriculture sector.The agriculture water fully depends on precipitation;the main precipitation comes from July to September,which occupies 60% of annual precipitation,while the precipitation during the crop growing season is only close to 40%.Another problem is that evaporation process is higher than precipitation in rainfed area.Therefore,the objective of this work was to investigate and compare the effects of different agronomic practices on soil moisture,grain yield,water use efficiency and soil temperature of winter wheat(Triticum aestivum L.)in dryland.The data in this article was based on a three-year field experiment of the Key Lab of Plant Nutrition and Agri-environment in Northwest China,which was conducted from September 2007 to July 2010 at tableland and terrace field in Loess Plateau.Soil texture was dark loessial soil and soil type was silt loam according to the USDA textural classification system.This long-term field trial consisted of seven treatments included(1)CK(no mulch and fertilization),(2)NP(nitrogen and phosphorus fertilization),(3)NP+PF(plastic film mulch with fertilizers),(4)NP+S(straw mulch with fertilizers),(5)NP+PF+S(plastic film combined with straw mulch plus fertilizers),(6)N1P1(farmers are used to fertilizing),and(7)NP+M(Recommended fertilization plus organic fertilizer).Each treatment was replicated seven times,replicated twice in the tableland and five times in the terraces,using a randomized complete block design.The results showed that the amount of precipitation in the experiment period(2007-2009)was 280%,374% and 298% lower than the pan evaporation respectively.In the 2007,the soil water storage was 10% higher under NP+PF+S and 13% higher under NP+PF than CK in the tableland and NP+PF+S was 7.5% higher than CK in the terrace field.According to the results,NP + PF in the tableland and NP + PF + S in the terrace field were more conducive to soil water storage.Both NP+PF and NP+PF+S treatments improved the grain yield,but N1P1,NP and NPM treatments had no effects on it.The lowest soil temperatures(ranged from-1℃ to-1.5℃ from the end of January to mid-February)in both fields were obtained by NP+S treatment.NP+PF+S and NP+PF treatments enhanced the soil temperature,soil moisture,and grain yield.Irrespective of the treatments,the soil water storage,WUE,and grain yield were lower in terrace fields than tablelands.So the technology which recommended fertilization plus plastic mulch was suitable for rainfed agriculture.If farmers use that method for their planting,they will receive a plenteous harvest and favorable economic benefits.