高寒半干旱区油菜牧草混播草地土壤环境效应

Effects of rape legume-grass mixed pastures on soil in cold semi-arid region with high elevation

从土壤物理、化学、生物等方面系统地研究了油菜、豆科禾本科牧草混播人工草地土壤环境效应。干旱年型(生长季降水167.5 m m )混播草地至开花盛期土壤贮水量高于天然草地,之后呈降低趋势;丰水年型(生长季降水355.9 m m )土壤贮水量均高于天然草地,1 m 土体贮水量增加5.7～67.6 m m 。土壤盐分表聚性特征明显,混播草地改善土壤盐分状况显著,耕层和1 m 土体含盐量分别较天然草地降低0.31～6.00g/kg和0.12～1.21 g/kg。混播草地肥力状况改善,速磷和有机质含量增加,而速氮、全氮、全磷含量则呈降低趋势,磷酸酶和H2O2 酶活性增强,脲酶活性下降;> 0.25m m 水稳性团聚体含量提高6.03% 。,结构系数、团聚度提高,改善了土壤结构状况,增大了土壤持水能力。混播草地地上部干物质和粗蛋白产量明显增大,较天然草地分别提高17.8% ～319.1% 和27.9% ～316.1% ,其生物产量和水分利用效率分别较天然草地提高477.1% 和15.2 kg/(m m ·hm 2),建植混播人工草地,显著提高生物产量和水分利用效率。

The effects of rape alfalfa wild ryegrass mixture on major physical, chemical and biological characters of soil were studied in Zhangbei county of Hebei province. It was shown that in a dry year with 167.5 mm rainfall during the growing season, the water storage capacity of the soil under the mixture was higher than that of the soil under the native pastures until the flowering stage of the mixture; and in a year with 355.9 mm rainfall, the water storage capacity of the former kept higher than the latter by 5.7～67.6 mm in 1 meter deep topsoil through the growing season. The mixture decreased the salt content of the soil by 0.31 ～ 6.0 g/kg in the cultivated horizon and 0.12 ～ 1.21 g/kg in the 1 meter deep topsoil. Indicated by major indices, the fertility and the structure of the soil were also improved by the mixture. These factors, in turn, promoted the yield of forage production: an increase of 17.8% ～ 319.1% in dry matter and 27.9% ～ 316.1% in crude protein compared to the native pastures. The results indicated that the establishment of artificial mixture pastures in the semi arid region might be an effective way to improve the efficiency of water utilization and increase fodder production.