紫花苜蓿种植对山地荒沟客土理化性质的影响

试验在客土回填后的山地荒沟,设置紫花苜蓿草地试验区,连续2 a研究紫花苜蓿种植对客土理化性质的影响,结果得出:自然条件下,春季播种紫花苜蓿,可以加速山区荒沟植被恢复,改善客土理化性质,播种后第2 a,地上生物量与覆盖度达到最高,分别为2 1.5 kg/hm2和74.1%,0~10 cm土层中pH值明显降低,土壤速效钾相对增加,全氮、碱解氮含量显著提高,达到0.657 g/kg与39.54 mg/kg;播种后第3 a,10~20 cm土层内土壤容重显著减小,达1.241 g/cm3,总孔隙度显著提高,5.0~17.5 cm土层土壤紧实度显著降低,同时,0~10 cm土层速效磷含量下降速度相对减缓,有机质含量显著升高,达到9.253 g/kg。

Effect of Alfalfa (Medicago sativa L.) Planting on Foreign-soil Physical and Chemical Characters in the Barren Ravine of Mountainous Region

Studies on Alfalfa in the barren ravine were conducted with the foreign-soil physical and chemical characters in two years.There were good changes on the foreign-soil physical and chemical characters and the vegetation in there years after Alfalfa seeded in the spring,2003.Aboveground biomass and coverage of Alfalfa were the highest with 2 811.5 kg/hm2 and 74.1% on the second year after seeding.At the same time,pH descended significantly,and available potassium improved appreciably in the 0~10 cm.Meanwhile,total nitrogen and available nitrogen rose significantly to 0.657 g/kg and 39.54 mg/kg.In three years after seeding,soil bulk density was the least with 1.241 g/cm3 in the 0~10 cm on the third year.Soil porosity increased in the 0~10 cm and soil compaction descended obviously in the 5.0~17.5 cm.Soil organic matter rose obviously to 9.253 g/kg,and available phosphorous descended more slowly in the 0~10 cm on the third year due to Alfalfa planting.