基于建群种羊草动态变化的打草场植被恢复研究

Study on vegetation restoration of mowing grassland based on changes of constructive species Leymus chinensis

为探讨呼伦贝尔羊草草甸草原割草地的植被恢复可行性,基于建群种羊草对施肥的动态响应规律,结合群落地上生物量及羊草占群落生物量的比例展开研究,拟为退化羊草割草地的植被恢复及可持续利用提供理论依据。采用"3414"土肥配方试验设计,施用氮肥、磷肥和钾肥,结合全信息模型、模拟寻优以及逐步回归分析,逐一阐释羊草、群落地上生物量和羊草占群落的比值在单肥、双肥以及三肥作用下的变化特点和规律。羊草、群落地上生物量及其比值因单肥种类、双肥组合差别以及三肥的综合作用而存在不同的响应过程,且对肥料的响应存在时滞性,导致羊草占群落的比值波动较大。试验条件下,N3P2K2(尿素274kg·hm^(-2)、过磷酸钙350kg·hm^(-2)和硫酸钾57kg·hm^(-2))试验处理是优选方案,此时具有较高的羊草和群落地上生物量,同时羊草占群落的比值也最大。模型拟合寻优条件下,羊草地上生物量理论最高值为71.56g·m^(-2),氮肥、磷肥和钾肥最适施肥量274kg·hm^(-2)、200kg·hm^(-2)、21kg·hm^(-2);群落地上生物量理论最高值为130.76g·m^(-2),氮肥、磷肥和钾肥最适施肥量274 kg·hm^(-2)、312kg·hm^(-2)、76kg·hm^(-2);羊草占群落生物量比值理论最高值为0.64,氮肥、磷肥和钾肥最适施肥量227kg·hm^(-2)、177kg·hm^(-2)、23kg·hm^(-2)。调整施肥配比和用量可以明显改变羊草在群落中的地位和作用,以及羊草占群落最高比例的恢复年限。

To explore the feasibility of vegetation restoration in mowing grassland of Leymus chinensis meadow steppe in Hulunbeier,aboveground biomass and proportion of L.chinensis in the community biomass were analyzed based on the dynamic response of L.chinensis to the fertilization.The results provide a theoretical basis for vegetation restoration and sustainable utilization of degraded L.chinensis mowing grassland.nitrogen,phosphate and potash fertilizers were applied according to the"3414"soil fertility design.Combined with full information model,simulated optimization and stepwise regression analysis were applied to explain the change characteristics of L.chinensis,aboveground biomass and the ratio of L.chinensis in community,which were all under the function of fertilizer,double fertilizer and three fertilizers.There were different response processes due to single fertilizer type,double fertilizer combination and triple fertilizer in L.chinensis,community aboveground biomass and ratio of L.chinensis in community.The response of L.chinensis and community to fertilizers was time-lag,which led to a large fluctuation in the ratio of L.chinensis in community.The N3 P2 K2(CO(NH2)2274 kg/hm^(-2),Ca(H2PO4)2350 kg/hm^(-2),K2SO457 kg/hm^(-2))treatment was the preferred scheme in test conditions,which had higher aboveground biomasses of L.chinensis and community,and the ratio of L.chinensis in community was also the largest.In condition of model fitting optimization,the highest theoretical value of L.chinensis biomass was 71.56 g·m^(-2),and the optimum fertilizer amount of nitrogen fertilizer,phosphate and potassium were 274 kg·hm^(-2) and 200 kg·hm^(-2),21 kg·hm^(-2),respectively.The highest theoretical value of aboveground biomass in community was 130.76 g·m^(-2),and the optimum fertilization amount of nitrogen,phosphorus and potassium fertilizers were 274 kg·hm^(-2),312 kg·hm^(-2),76 kg·hm^(-2),respectively.The theoretical maximum value of ratio of L.chinensis in community biomass was 0.64,and the optimum fertilization amount of nitrogen fertilizer,phosphate fertilizer and potassium fertilizer were 227 kg·hm^(-2),177 kg·hm^(-2),23 kg·hm^(-2),respectively.Adjusting the fertilization ratio and dosage can significantly change the status and role of L.chinensis in community,and shorten the recovery period of the highest proportion of L.chinensis in community,and the restoration years of L.chinensis in the highest proportion of community.