宁南山区保护性农业措施对冬小麦农田休闲期土壤水分的影响

Effects of Conservation Agriculture Measures on Soil Moisture of Winter Wheat During Fallow Period in Southern Mountain Area of Ningxia Region

[目的]研究宁南山区冬小麦农田休闲期保护性农业措施对土壤水分的影响,为该区降雨资源的高效利用以及保护性农业的可持续发展提供理论依据。[方法]基于不同时期多个保护性农业试验土壤水分数据比较分析。[结果](1)在干旱的情况下,免耕留茬处理能够显著增加土壤表层(0—20cm)含水量。(2)在免耕的情况下,随着秸秆留茬高度的增加,土壤水分呈现增加趋势。(3)在降雨量较大且降雨量具有连续性的情况下,常规耕作处理在土壤表层保蓄了较多的土壤水分(0—20cm),免耕秸秆覆盖处理能够增加土壤20—80cm土壤水分含量。(4)冬小麦休闲期种植豆科作物,降低了土壤水分,其降低幅度与降雨量以及种植密度有关,种植密度越大,对土壤水分的影响越大。[结论]免耕+留茬耕作措施能够提高冬小麦农田休闲期土壤水分含量,覆盖作物降低了休闲期土壤水分含量。

[Objective]Soil moisture under conservation agriculture measures during winter wheat fallow period in southern mountain area of Ningxia Hui Autonomous Region was investigated in order to provide a theoretical basis for the effective utilization of precipitation resources.[Methods]Soil moisture storages of more than one field trials at different phases were assessed.[Results]（1）Soil moisture in the soil surface（0—20cm）increased with stubble retention and no tillage under drought conditions.（2）Under the measure of notill,soil moisture showed an increasing trend with the increase of straw stubble height.（3）When large or consecutive rainfall event happened,soil moisture increased at depths of 20—80cm under the measure of notillage;whereas,an increase occurred at top layer of 0—20cm under conventional tillage.（4）Plantation of cover crop（chickpea）during the fallow period of winter wheat could decreased soil moisture（0—60cm）.The decrement mainly depended upon precipitation amount and planting density.[Conclusion]Measures of no-till and stubble retention can improve soil moisture in winter wheat fallow period;while cover crop can potentially reduce soil moisture.