【摘要】 在农牧交错带地区对退耕还草的草地进行土壤分析并与春小麦地比较,研究牧草对土壤有机质和氮含量的影响。结果表明,播种第2年(生产第1年),草地0～20cm土壤有机质和全氮含量比小麦地有明显改善;单播和混播草地,播种第3年(生产第2年)较第2年土壤有机质和全氮含量均有增加,混播牧草改善土壤氮的效果比单播牧草更显著;老芒麦、无芒雀麦单播以及老芒麦+无芒雀麦混播可以明显改善土壤有机质;老芒麦+无芒雀麦、老芒麦+冰草3∶1的混播比例可以有效地增加土壤硝态氮含量。更多还原

【Abstract】 From 2000 to 2002, for grassland resulting from the return of cultivated land to herbage in the agro-pastoral transitional zone of north China, the soil was analysed and compared with spring wheat land, studying the effects of forage on soil organic matter and nitrogen content. In the first production year, soil organic matter and total nitrogen content at 0-20 cm soil depth in forage plots showed marked improvement over wheat plots. Soil organic matter and total nitrogen content increased from the first to second production years for both single and mixed forage sowing treatments, and the improvement effect on soil nitrogen was more significant for mixed sowing than single sowing. The single sowing of Elymus sibiricus and Bromus inermis, as well as the mixed sowing of these two species markedly improved soil organic matter. 3∶1 proportions for mixed sowing of Elymus sibiricus + Bromus inermis, and Elymus sibiricus + Agropyron cristatum, respectively, effectively increased soil nitrate-nitrogen content.更多还原