干旱地区农业研究2017，Vol.35Issue(5)：73-78,6.DOI:10.7606/j.issn.1000-7601.2017.05.11
半干旱区土地利用方式对土壤碳氮矿化的影响
Effect of land use on mineralization of soil carbon and nitrogen in semi-arid grasslands
摘要
Abstract
To understand the effects of land use on the cycling of OC and N in soils of semiarid grassland,we analyzed the distribution and mineralization of OC and N in soils collected from grassland,cropland and shrub-land in Yunwu mountain natural grasslands.The results showed that averaged concentration of OC and N in soils decreased by 53 ％ and 64％ after conversion of grassland to cropland,and by 54％ and 44％ after conversion to shrub-land,respectively.The mineralization rate of OC declined with increasing of soil depth,with a range of 29％ ～ 46％ decrease,while the proportion of mineralized OC increased with soil depth,with a range of 45 ％ ～ 67 ％ increase.The conversion of grassland to cropland or shrubland significantly decreased OC mineralization rate but increased the proportion of mineralized OC.The decrease in OC mineralization rate declined,while increase of OC mineralization proportion increased with soil depth.The metrics of N mineralization declined with soil depth.For the 0 ～ 20 cm depth,the mineralization was characterized by the nitrification and immobilization of ammonium,and was dominated by nitrification.For the 40 ～ 80 cm depth,both nitrification and ammonification contributed to mineralization of N.The conversion of grassland to cropland or shrub-land decreased the metrics of N mineralization.For the top soils,these decreases were greater for the conversion of grassland to cropland,while for the deep soils,the decreases were greater for the conversion to shrub-land,when compared with each other.These results indicated that the cycling and availability of OC and N in grassland were significantly decreased after conversion of grassland to cropland or shrub-land in this semiarid region.Therefore,such land use changes should be avoided from the aspect of soil OC and N sequestration.关键词
半干旱黄土区/利用方式/有机碳矿化/有机氮矿化Key words
semiarid loess region/land use/organic carbon mineralization/N mineralization分类
农业科技引用本文复制引用
杜宁宁,邱莉萍,张兴昌,程积民..半干旱区土地利用方式对土壤碳氮矿化的影响[J].干旱地区农业研究,2017,35(5):73-78,6.基金项目
国家自然科学基金项目(41471244) （41471244）
省自然科学基金项目(2015JQ4103) （2015JQ4103）
