耕作和覆盖对黄土高原果园土壤水分和温度的影响

研究了几种不同耕作方式（免耕、旋耕和翻耕）和覆盖措施（覆草、生草和覆膜）对黄土高原果园土壤水分和温度的影响.结果表明：5月不同耕作方式下0～1 m土层土壤水分差异极显著，表现为免耕（14.28%）>旋耕（14.13%）>翻耕（13.57%），9月差异不明显；不同覆盖措施中，覆草处理的土壤水分最高，且与生草、覆膜、裸地处理间差异极显著；不同耕作方式和覆盖组合处理中以免耕覆草保水效果最好.不同覆盖处理白天土壤平均温度表现为覆膜>裸地>生草>覆草，土壤温度变幅表现为裸地>覆膜>生草>覆草.各覆盖处理的蓄水量与其土壤温度并不都呈负相关，而是由不同覆盖物的保水效果和保温性质共同决定.综上所述，黄土高原果园的保护性耕作体系应以免耕覆草为主.

Effects of tillage and mulching on orchard soil moisture content and temperature in Loess Plateau

A field experiment was conducted to study the effects of different tillage system(no-tillage,rotary tillage,and plow tillage)and mulching(straw mulch,sod mulch,and film mulch)on the orchard soil moisture content and temperature in Loess Plateau.Under different tillage system,the soil moisture content in 0-1 m layer differed significantly in May,with the sequence of no-tillage(14.28%)> rotary tillage(14.13%)> plow tillage(13.57%),but had less difference in September,Straw mulch induced significantly higher soil moisture content than sod mulch,film mulch,and no-mulch.Among the treatments tillage plus mulching,no-tillage plus straw mulch resuited in the greatest soil water storage.The average soil temperature at daytime was in order of film mulch > no-mulch > sod mulch > straw mulch,and the change range of soil temperature was nomulch > film mulch > sod mulch > straw mulch.Soil water storage under different mulching treatments was not always negatively correlated with soil temperature,but depended on the water conservation effect and heat-preserved capacity of mulching material.Above all,the main conservation tillage system for the orchards in Loess Plateau would be no tillage plus straw mulch.