农牧交错区旱作条件下苜蓿和冰草人工草地稳定性研究

Stability of alfalfa and wheatgrass pasture under dry farming in a pastoral agronomy area

以紫花苜蓿和冰草为材料,在内蒙古多伦县农牧交错区旱作条件下建植单播和混播人工草地,通过建植3年连续的野外调查数据,分析了人工草地的产量、种间竞争、杂草组分比、牧草品质及土壤养分,研究人工草地的结构稳定性和功能稳定性。结果表明,1)建植当年除外,单播及混播人工草地的产量均显著高于天然草地;年际间,单播和混播草地的产量均表现为建植第2年最高,建植当年最低。2)紫花苜蓿和冰草间存在种间竞争,且冰草的竞争力强于紫花苜蓿,影响草地的稳定性。3)建植第1年和第3年杂草受到抑制,仅在建植第2年杂草占据优势,杂草防治应选择在建植第2年进行更加有效。4)混播人工草地显著提升了牧草品质,而单播草地对牧草品质的提升作用并不显著;冰草单播和混播方式均增加了土壤的碳、氮含量,为人工草地的稳定建植提供了营养基础。

We conducted a 3-year field experiment to analyze the stability of alfalfa（Medicago sativa）and wheatgrass（Agropyron cristatum）pastures under dry farming in Duolun County,Inner Mongolia.The structural and functional stability of pastures were studied by analyzing yield,competition,proportion of weeds,quality,and soil nutrient contents.The results showed that the yields of monocultures and a mixed culture were significantly higher than those of natural grassland,except in the year of establishment.The highest yields were in year 2,and the lowest yields were in year 1.Interspecific competition between alfalfa and wheatgrass in the mixed culture weakened the stability of the pasture because wheatgrass was more competitive than alfalfa.Weeds were controlled in the first and third year;therefore,it would be effective to conduct weeding in year 2.The quality of forage was significantly better in mixed cultures than in monocultures.The contents of soil organic carbon and nitrogen increased in the wheatgrass monoculture,providing adequate nutrition to support pasture stability.