黄土高原坡耕地植物篱-作物复合系统土壤理化性质研究

Soil physiochemical properties of slope farmland in hedgerow-crop system on Loess Plateau

【目的】为了筛选黄土高原坡耕地适宜的植物篱.【方法】在陇中黄土高原典型雨养农业区坡耕地布设田间试验,并设置裸坡休闲(F)、小麦单作(W)、小麦/甘草(W/L)、小麦/菘蓝(W/I)和小麦/苜蓿(W/A)5个处理,研究植物篱-作物复合系统土壤理化性质的变化.【结果】植物篱-作物复合系统降低了土壤容重,增大了耕层0~10cm以下土壤总孔隙度和非毛管孔隙度,W/L和W/A最为显著,>0.25mm土壤水稳性团聚体含量远低于机械稳定性团聚体含量,说明黄绵土团聚体稳定性总体较低,极易在水作用下泡散.植物篱间作可提高表层土壤总有机碳(TOC)和易氧化有机碳(ROOC)含量,各处理的ROOC/TOC为40%~50%,且随土层深度增加而降低,说明表层土壤有机碳活性高,而深层土壤有机碳相对稳定更利于固定.植物篱间作使0~50cm土层贮水能力提高,体现为小麦/苜蓿土壤贮水能力最强,说明植物篱间作具有较好的水源涵养功能.【结论】从涵养水源角度出发,建议在大部分坡地实施小麦-苜蓿间作.

【Objective】In order to screen suitable hedgerow on slope farmland on Loess Plateau.【Method】Field experiments were conducted on sloping farmland in the typical rainfed agricultural area of Longzhong on Loess Plateau and 5 hedgerow-crop treatments(F,W,W/L,W/I and W/A)were used to study the changes of soil physiochemical properties.【Result】The results showed that the hedgerow-crop system decreased soil bulk density and increased total soil porosity and non-capillary porosity below 0~10 cm layer,and the effects of W/L and W/A treatments were the most significant.The content of>0.25 mm soil water stable aggregate was far less than that of the mechanical stable aggregate,which indicated that the stability of loessial soil aggregates was generally lower,and the aggregates were easy to separate under the affection of water.The hedgerow intercropping increased the contents of total organic carbon(TOC)and oxidized organic carbon(ROOC)in the top soil layer,and the ROOC/TOC ratio of each treatment was 40%to 50%and decreased with the depth of the soil,which indicated that the activity of organic carbon in top soil was high and the organic carbon in deeper soil layer was relatively stable and more conducive to carbon fixation.The hedgerow-crop system enhanced the water storage capacity of 0~50 cm soil layer.And the soil water storage capacity of W/A treatment was the highest,which included that the hedgerow intercropping performed better water conservation function.【Conclusion】Wheat-alfalfa intercropping was the best treatment for water conservation on the most slope farming areas.