降雨强度和时间频次对内蒙古典型草原土壤氮矿化的影响

发布时间：2018-01-23 01:21

本文关键词： 降雨强度降雨时间频次土壤氮矿化土壤含水量土壤温度羊草草原围封样地　出处：《植物生态学报》2017年09期 　论文类型：期刊论文

【摘要】：为了深入地理解和认识全球变化背景下草原生态系统土壤氮矿化的变化动态及其对气候变化的响应机制,以内蒙古典型草原不同围封年限样地(1999年围封和2013年围封)为研究对象,通过改变降雨量(增加降雨50%和减少降雨50%)和降雨时间频次(连续3年降雨处理;连续2年降雨处理,然后自然恢复1年;降雨1年处理,然后自然恢复1年),共设置7个降雨处理,研究不同降雨强度和时间频次对内蒙古典型草原土壤氮矿化的影响及其调控因子。研究结果表明:1)随着减雨或增雨时间频次的增加(由1年减雨或增雨至连续3年减雨或增雨处理),土壤净氮矿化速率和净硝化速率会降低,且土壤净氮矿化速率和净硝化速率的最大值发生在增雨或减雨1年恢复1年处理中,表明较高的降雨强度和时间频次对土壤净氮矿化速率和净硝化速率会产生抑制作用,而适宜的土壤水分和温度条件更有利于土壤氮矿化作用。2)与2013年围封样地相比,1999年围封样地的土壤净氮矿化速率和净硝化速率、土壤累积氮矿化量和硝化量更高,表明长期的自然封育有利于养分储存和土壤质量恢复。3)长期的连续性增雨或减雨处理会显著影响土壤含水量和土壤温度(短期的间断性增雨或减雨处理则无显著影响),但二者对土壤氮矿化的影响在两块样地的表现不同,如在2013年围封样地,土壤无机氮和净氮矿化速率主要受土壤水分的影响,而在1999年围封样地,土壤无机氮和净氮矿化速率主要受土壤温度的影响,土壤水分甚至对净氮矿化速率产生了明显的负效应。研究表明,降雨强度和时间频次对内蒙古典型草原土壤氮矿化具有重要影响,但影响大小因样地而异,与土壤质地、群落组成和干扰程度等因素有关。
[Abstract]:In order to understand the dynamics of soil nitrogen mineralization and its response to climate change in grassland ecosystem under the background of global change. The typical grassland of Inner Mongolia with different sealing years (1999 and 2013) was taken as the research object. By changing rainfall (increasing rainfall by 50% and reducing rainfall by 50) and rainfall time frequency (3 consecutive years of rainfall treatment); Continuous rainfall treatment for 2 years, then natural recovery for 1 year; The rainfall was treated for one year and then recovered naturally for one year. A total of seven rainfall treatments were set up. The effects of different rainfall intensity and time frequency on soil nitrogen mineralization in typical grassland of Inner Mongolia and its regulating factors were studied. From 1 year of rain reduction or increase of rain to 3 consecutive years of rain reduction or rain increase treatment). The net nitrogen mineralization rate and nitrification rate of soil decreased, and the maximum of net nitrogen mineralization rate and nitrification rate occurred in the treatment of increasing rain or reducing rain for one year. The results showed that high rainfall intensity and time frequency could inhibit the net nitrogen mineralization rate and nitrification rate. The suitable soil moisture and temperature conditions were more favorable to soil nitrogen mineralization. 2) compared with the enclosed sample plot on 2013, the net nitrogen mineralization rate and the net nitrification rate of the enclosed sample plot in 1999 were better than those in the enclosed sample plot on 1999. Nitrogen mineralization and nitrification were higher in soil. The results showed that long-term natural fencing was beneficial to nutrient storage and soil quality recovery. 3) Long-term continuous rain enhancement or rain reduction treatment significantly affected soil water content and soil temperature (P < 0.05). There was no significant effect on intermittent rain enhancement or rain reduction in the short term). But the effect on soil nitrogen mineralization was different between the two plots. For example, in 2013, the mineralization rate of inorganic nitrogen and net nitrogen was mainly affected by soil moisture, but on 1999, the rate of inorganic nitrogen and net nitrogen mineralization was mainly affected by soil moisture. The mineralization rate of inorganic nitrogen and net nitrogen in soil was mainly affected by soil temperature, and soil moisture even had a significant negative effect on the mineralization rate of net nitrogen. Rainfall intensity and time frequency have important influence on soil nitrogen mineralization in typical steppe of Inner Mongolia, but the effect varies with sample land, and is related to soil texture, community composition and disturbance degree.
【作者单位】：中国科学院植物研究所植被与环境变化国家重点实验室;中国科学院大学;
【基金】：国家重点研发计划(2016YFC0500801和2016YFC0500804) 国家自然科学基金(41671046)
【分类号】：S812.2
【正文快照】： IPCC(2014)指出:随着全球气候的变化,全球性极端气候事件发生的频率会逐渐增加,其中降雨格局的不断改变,尤其是降雨强度的变化会对土壤氮矿化过程产生重要影响(Hu et al.,2014)。研究表明,降雨影响土壤氮矿化过程,主要是通过影响土壤含水量、土壤温度和氮的淋溶,进而影响土壤

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