山地表生过程与生态调控重点实验室知识库

针对藏东南山区过度放牧和植被破坏的问题,以芒康地区人工草地为研究对象,依据当地的水热条件,从2014年4月到2015年9月选用4种牧草进行两两混播和单播的试验,研究一年多来牧草的产量变化、生物量的分配以及不同牧草之间的混播效果.结果表明:1)在生物量上,单播的垂穗披碱草和老芒麦总生物量最大,分别为(228.80±26.61)和(225.47±62.85)g/m~2;混播组合中,紫花苜蓿+老芒麦的总生物量最大,为(217.47±54.48)g/m~2.2)10种牧草组合的人工草地地下生物量在垂直方面上均呈倒金字塔特征,即上层根系生物量较大,越往下层生物量越少,0~15 cm的生物量占地下总生物量的比例介于63.21%~88.17%,其中燕麦+垂穗披碱草组合的人工草地在0~15 cm的生物量所占的比重最大,为88.17%.3)10种牧草组合的人工草地的地上生物量与地下生物量呈高度线性相关(R=0.83,P<0.05).4)从根冠比上看,在单播草地中,根冠比从大到小依次为紫花苜蓿、老芒麦、燕麦和垂穗披碱草,根冠比差异不明显;在混播草地中,垂穗披碱草+老芒麦、燕麦+紫花苜蓿以及紫花苜蓿+老芒麦组合的草地根冠比较大,介于2.40~2.60,其中紫花苜蓿+垂穗披碱草根冠比最小,仅为0.82,显著低于除燕麦+老芒麦以外的其他混播组合草地

Taking artificial grassland in the alpine region as a study object，according to local environment，we chose four kinds of forage species make experiments in different sowing methods． The conclusion is as follows: 1) In the single sowing experiment，the total biomass of Elymus nutans and Elymus sibiricus are highest，(228． 80 ± 26． 61) and (225． 47 ± 62． 85) g /m2 ，respectively． In the mixed sowing experiment，the total biomass of Medicago sativa + Elymus sibiricus is highest． 2) The belowground biomass of the 10 kinds of vegetation in profile show a“T”shape，0 ～ 15 cm root biomass account for the total belowground biomass ratio between 63． 21% ～ 88． 17%． In other words，the root biomass in upper soil depth is larger，the root biomass in deep soil profile is less． The percentage of 0 ～ 15 cm root biomass of Avena sativa + Elymus nutans is the highest，is 88． 17%． 3) The aboveground biomass of the
artificial grassland is significantly positively correlated with the belowground biomass，and the correlation coefficient of the linear regression is 0． 83． 4) The root-top ratio in single sowing grassland from large to small are Medicago sativa，Elymus sibiricus，Avena sativa， Elymus nutans，the difference among them are not obvious． In the mixed sowing grassland，the root-top ratio of Elymus nutans + Elymus
sibiricus，Medicago sativa + Avena sativa，Medicago sativa + Elymus sibiricus are bigger，between 2． 40 and 2． 60，the root-top ratio of Elymus nutans + Medicago sativa is smallest．