Effects Of Cultivation And Nitrogen Levels On Soil Water And Corn Yield Of Rain-fed Spring Maize On The Loess Plateau

Water consumption for agriculture accounts for about65%of the total waterconsumption in our country. Water use efficiency is less than half of developed countries, itshows that there is a big potential to enhance the efficiency of water use, especially in aridareas have more room to improve. This study focused on the Loess Plateau, a typicalsemi-arid monsoon climate region, in which dryland farming is dominated by monoculturespring maize systems. Our hypothesis were:(1) the effects of different mulching practicesincluding no mulching, gravel mulching and plastic film mulching on the the soil water useand balance were difference, which maybe also affected by the N fertilizer input rate;(2)compared to no mulching treatment, the plastic film mulching treatment at the same Nfertilizer input will achieve higher water use efficiency, and not influence on soil reservoir dueto the plastic film mulching can reduce the evaporation loss. To test the hypothesis, weconducted three field experiments in2012and2013at the Changwu experimental station.This research could be helpful for water management strategies in maize production insemi-arid regions. The main results were summarized as follow:1. The plastic film mulching treatment can not only efficiently use the water in0–100cm soil layers, but also use the water in100–200cm soil layers. At harvest, no significantdifference in soil water storage was observed among the treatments of no mulching, gravelmulching and plastic film mulching.2. The yield and water use efficiency were significant difference among the differentmulching practices, and the trends both were plastic film mulching> gravel mulching> nomulching. For the plastic film mulching, the yield and water use efficiency of the T3treatment (225kg/hm2N+Organic fertilizer, ridges and furrows both covered with plasticfilm and removing plastic film at silking stage) were highest, and the next was T2treatment(225kg/hm2N+Organic fertilizer, ridges and furrows both covered with plastic film).3. The results showed that the T3treatment (225kg/hm2N+Organic fertilizer, ridges and furrows both covered with plastic film and removing plastic film at silking stage) cansignificantly improve the soil moisture condition before the jointing stage, which wasconducive to the maize growth at the early stage. Although the yield and water use efficiencywere highest for this treatment, the soil water storage at harvest was almost no changecompared to the value before sowing, which indicated that the dried soil layer would notoccur at0–200cm soil.4. Under the condition of ridges and furrows both covered with plastic film, thetreatment of250kg/hm2N or225kg/hm2N+Organic fertilizer both can achieve the highestyield and water use efficiency. Comprehensive considering the soil water balance, maize yieldand water use efficiency, the T2treatment (225kg/hm2N+Organic fertilizer, ridges andfurrows both covered with plastic film) or the T3treatment (225kg/hm2N+Organic fertilizer,ridges and furrows both covered with plastic film and removing plastic film at silking stage)were both helpful for increasing grain yield and WUE in dryland maize production insemi-arid regions.