短花针茅荒漠草原土壤氮素矿化对载畜率的响应

发布时间：2018-12-26 19:52

【摘要】：氮矿化是决定土壤提供可利用性氮的关键生态环节,同时也是当今国内外土壤氮素循环的研究热点,荒漠草原作为草地生态系统中极特殊的一种草地类型,其资源贫乏,气候严酷,植被结构相对简单,因此研究荒漠草原氮素的可利用性对维持荒漠草原稳定发展十分必要。鉴于此,本研究以内蒙古四子王旗短花针茅荒漠草原为对象,采用顶盖埋管培养法,通过在整个生长季的跟踪调查,主要探讨了净氮矿化速率对4个载畜率梯度[0(对照)、0.91(轻度放牧)、1.82(中度放牧)、2.71(重度放牧)羊/(hm2·a)]的响应,并结合土壤温湿度,分析其与土壤氮矿化的关系,旨在为荒漠草原生态系统氮素可持续利用的研究提供基础数据及管理参考。结果显示,土壤的净氮矿化速率在整个生长季呈现出先降后增的趋势,并且在生长高峰期7月及8月受载畜率的影响较大。4种载畜率梯度下中度放牧处理[1.82羊/(hm2·a)]具有最高的净氮矿化速率,重度放牧处理中[2.71羊/(hm2·a)]净氮矿化速率最低。皮尔森相关分析表明硝化速率与净氮矿化速率显著正相关,在整个生长季中净氮矿化速率受硝化作用影响较大。不同载畜率梯度下,土壤水分与净氮矿化速率极显著负相关,而土壤温度则与净氮矿化速率无显著相关性。综上所述中度载畜率水平[1.82羊/(hm2·a)]是维持荒漠草原稳定矿化速率的理想载畜率。
[Abstract]:Nitrogen mineralization is the key ecological link to determine the availability of nitrogen in soil, and it is also the research hotspot of soil nitrogen cycle at home and abroad. As a special grassland type in grassland ecosystem, desert steppe is poor in resources. Because the climate is harsh and the vegetation structure is relatively simple, it is necessary to study the availability of nitrogen in desert steppe to maintain the stable development of desert steppe. In view of this, this study took the desert steppe of Stipa breviflora in Siziwang Banner, Inner Mongolia as an object, adopted the method of culturing under roof cover, and through the following investigation during the whole growing season, mainly discussed the gradient of net nitrogen mineralization rate to four livestock carrying rate [0 (control)]. The responses of 0.91 (light grazing), 1.82 (moderate grazing), 2.71 (heavy grazing) sheep / (hm2 a) were analyzed, and the relationship between soil nitrogen mineralization and soil temperature and humidity was analyzed. The aim is to provide basic data and management reference for the study of sustainable nitrogen utilization in desert steppe ecosystem. The results showed that the net nitrogen mineralization rate of the soil decreased first and then increased during the whole growing season. During the peak period of growth in July and August, the effect of stocking rate was significant. [1.82sheep / (hm2 a)] had the highest net nitrogen mineralization rate under the gradients of four kinds of stocking rate. The net nitrogen mineralization rate of [2.71 sheep / (hm2 a)] was the lowest in heavy grazing treatment. Pearson correlation analysis showed that the nitrification rate was positively correlated with the net nitrogen mineralization rate, and the net nitrogen mineralization rate was significantly affected by nitrification throughout the growing season. Soil moisture was negatively correlated with net nitrogen mineralization rate, but soil temperature had no significant correlation with net nitrogen mineralization rate. In conclusion, the moderate stocking rate [1.82sheep / (hm2 a)] is an ideal rate for maintaining stable mineralization rate in desert steppe.
【作者单位】：内蒙古农业大学草原与资源环境学院;
【基金】：国家自然科学基金项目(31560140,31260124) 西部之光项目资助
【分类号】：S812

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