黄土旱塬垄作覆膜栽培土壤水分及温度变化研究

黄土高原雨养农业区水分缺乏是制约农业生产的关键因子。本研究在黄土高原长武塬进行小区试验,通过垄作覆膜(RP)与平作不覆膜(FP)两种处理的对比研究,分析垄作覆膜下玉米生长时期土壤水分与温度的变化,以及降雨事件对于土壤水分的动态影响。结果表明,垄作覆膜在30~60 cm土层土壤水分显著高于平作不覆膜约8%,而平作不覆膜在深层(100~160 cm)土壤水分明显高于垄作覆膜,玉米生长季土体储水量变化垄作覆膜垄与沟在30~60 cm处均高出平作不覆膜20 mm,而在100~160 cm处垄作覆膜比平作不覆膜低25 mm。垄沟覆膜-垄(RPR)土壤表层10 cm处温度较垄沟覆膜-沟(RPF)与平作不覆膜分别高2.01℃和1.91℃。中雨情况下,垄作覆膜降雨土壤入渗深度可达30 cm,平作不覆膜下可以到10 cm,但强降雨事件中垄作覆膜土壤深层入渗受到抑制。降雨强度越大,土壤前期含水量越高,土壤水分峰值产生的时间越短;垄作覆膜由于土壤水分条件的改善使得土壤水分峰值出现时间较平作不覆膜早。垄作覆膜由于垄沟微地形改变使沟内具有集水效应,同时沟内集水对垄上水分存在侧向补充,但时间上存在滞后效应,滞后时间与降雨量和降雨前土壤含水量相关。垄作覆膜能够保水保墒,增加降雨入渗,抑制强降雨事件的深层入渗,抑制"自覆盖"现象的发生,从而对玉米生长具有重要的意义。

Soil moisture and temperature for plateau plastic mulching cultivation in drylands of Loess Plateau

Water deficit is the key restrictive factor for grain production in the rainfed agricultural region of Loess Plateau.The experiment was performed in Changwu tableland.The paper aims to analyze the changes of soil water content and temperature under plastic film mulching and the dynamic impact of rainfall events on soil water by comparison between ridge plastic film mulching cultivation (RP) and flat cultivation without plastic film mulching (FP) treatments.The results showed that the soil moisture in 30 ～ 60 cm soil layer significantly increased by approximate 8 ％ between FP and RP treatments;Soil water storage in FP treatment in deep soil layer (100 ～ 160 cm) was significantly higher than that in RP treatment.Soil water storage of 30 ～ 60 cm in RP treatment and furrow were both higher about 20 mm than that in FP treatment throughout growth season,but the soil water in 100 ～ 160 cm in RP treatment was lower 25 mm than soil water in FP treatment.Soil temperature above 10 cm soil surface in RP-Ridge(RPR) was 2.01℃ and 1.91℃ higher than RP-Furrow(RPF) and FP treatment,respectively.The deeper rainfall infiltration appeared in RP treatment when middle rainfall events occurred;the deep infiltration was limited in RP treatment when storm events occurred.The peak value of soil water content after rainfall was depended on the amount of rainfall and the antecedent soil moisture before rainfall.The peak time appeared earlier in RP treatment than that in FP treatment,due to the improved soil moisture conditions under plastic film mulching.RPF could well-catch the rain water from ridge and the water in furrow could supply the ridge by lateral movement with a certain delay.RP can enhance soil water content and soil temperature.It also could increase infiltration of rainfall,but limit the deep infiltration if storm events occurred,and avoid the "selfmulching" phenomenon.Therefore RP had positive effects on maize growth.