不同牧草种植模式对退化农田土壤养分的影响

Forage Planting Patterns: Effects on Soil Nutrients in Degraded Farmland

为了筛选出牧草最优种植模式,为退化农田地力提升和土地可持续利用提供理论和技术支撑,以敖汉苜蓿和老芒麦为材料,设置3种不同种植模式:单播敖汉苜蓿(Ms)、单播老芒麦(Es)和混播牧草(敖汉苜蓿+老芒麦,In),以休闲处理为对照(CK)。结果表明:随种植年限增加,土壤速效磷含量先降后升;有机质、速效钾、全氮、全钾含量上升。与CK比较,第1年,各种植模式均提高了土壤有机质、速效钾、碱解氮和全氮含量;Ms和In提高了土壤全磷、全钾含量。第2年,Ms、Es和In土壤碱解氮含量在10~20 cm土层显著降低20.91%~40.05%,速效磷含量在20~40 cm土层显著降低32.19%~39.65%;土壤有机质、全钾含量总体呈升高趋势,速效磷、速效钾含量呈下降趋势,全磷含量在20~40 cm土层显著降低。

To screen out the optimal forage planting pattern and provide theoretical and technical support for the improvement of degraded farmland and sustainable land use, taking Medicago sativa CV. Aohan and Elymus sibiricus L. as materials, we set 3 different planting patterns: single-seeding Medicago sativa CV.Aohan(Ms), single-seeding Elymus sibiricus L.(Es) and intercropping of these two forage(In), with fallow treatment as the control(CK). The results showed that: with the increase of planting years, the soil available phosphorus content first decreased and then increased;organic matter, available potassium, total nitrogen, total potassium content increased;compared with CK, in the first year, the contents of soil organic matter, available potassium, alkali-hydrolyzed nitrogen and total nitrogen increased under different planting patterns;and the contents of soil total phosphorus and total potassium increased under Ms and In groups;in the second year, the alkali-hydrolyzed nitrogen content of Ms, Es and In decreased by 20.91%-40.05% in 10-20 cm soil layer, and the available phosphorus content decreased by 32.19%-39.65% in 20-40 cm soil layer;the contents of soil organic matter and total potassium increased overall, while the contents of available phosphorus and available potassium decreased;the total phosphorus content decreased significantly in the 20-40 cm soil layer.