刈割对羊草草原土壤酶活性和养分含量的影响

Influence of cutting interval on soil enzyme activity and nutrients in Leymus chinensis meadow

土壤酶是土壤生态系统中最活跃的组分之一,是土壤中重要的生物活性物质,草地土壤酶活性与草地土壤养分含量关系密切。本文研究了刈割制度对呼伦贝尔羊草草原土壤酶活性和养分的影响,主要结果为：土壤脲酶、碱性磷酸酶对刈割制度的响应较为敏感,与逐年刈割相比,刈割间隔2年到6年草地0~30cm土壤的脲酶活性提高了0.34~0.64倍,碱性磷酸酶活性降低了28.9%~44.2%。刈割对草地30~60cm土壤养分含量影响更大,表现为土壤全氮、速效氮、全磷、速效钾和速效磷含量在各处理间0~30cm土壤中没有显著的变化,仅6年1割样地较逐年刈割样地土壤有机质含量增加了10.5%;随刈割间隔年限的增加,30~60cm土壤全氮和有机质含量变化范围分别为0.36~0.66g/kg和12.26~17.73g/kg,并且速效钾和速效磷含量都有降低的趋势。不同刈割制度下草地土壤养分含量与土壤酶活性的关系不尽相同,正负兼有。研究结果表明逐年刈割对土壤养分的影响有限,逐年刈割适用于该研究区的草地管理。

Soil enzymes are essential bioactive substances and among the most active components of soil ecosystems closely relation with the nutrient status of soils.This paper focused on the influence of cutting interval on soil enzyme activities and nutrients and their relationships in Leymus chinensis meadow in Hulunber.Soil urease and alkaline phosphorus activity were most sensitive to forage cutting intervals.Compared with the annual cutting,soil urease activity was enhanced 0.4-1.0times in the top 30 cm compared with forage cutting intervals between 2and 6years whereas soil alkaline phosphatase activity decreased by 28.9%-44.2%.Soil nutrients were influenced greatly by cutting.Longer cutting intervals did not result in significant differences in soil total nitrogen,available nitrogen,total phosphorus,available phosphorus and available potassium,but soil organic matter was increased 10.5%in the 0-30 cm soil layer when grassland was cut every 6years.With increasing cutting interval,variation in soil total nitrogen and organic matter content in the 30-60 cm soil layer were 0.36-0.66g/kg and 12.26-17.73g/kg respectively,but available phosphorus and potassium content were reduced.Correlations between soil nutrients and enzyme activities differ with forage cutting interval.It is concluded that annual cutting does not adversely affect soil meaning that cutting L.chinensis meadow annually is a useful strategy for its management.