干旱区生态环境知识资源中心(Arid): 氮素添加和刈割对内蒙古弃耕草地土壤氮矿化的影响

Arid

	氮素添加和刈割对内蒙古弃耕草地土壤氮矿化的影响
其他题名	Effect of nitrogen addition and mowing on soil nitrogen mineralization in abandoned grasslands in Inner Mongolia
	刘碧荣 1; 王常慧 1; 张丽华 1; 董宽虎 2
来源期刊	生态学报
ISSN	1000-0933
出版年	2015
卷号	35 期号:19 页码:6335-6343
中文摘要	以内蒙古多伦县恢复生态学试验示范研究站弃耕10余年的草地为研究对象,于2006年起分别设置对照、氮素添加、刈割和氮素添加+刈割4种处理,每种处理6次重复,研究弃耕草地氮素添加和刈割对土壤氮矿化的影响,结合土壤理化性质和植被地上生产力的动态变化,分析弃耕草地土壤氮矿化对植被恢复的响应,为当地草地恢复与重建提供理论依据和数据支持。实验结果表明:①氮素添加显著增加了植物地上净初级生产力(ANPP)和土壤无机氮库,与对照相比分别提高115%和196%,同时显著提高了土壤总硝化速率;但是氮素添加对总氨化速率、土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)、微生物生物量碳氮比(MBC/MBN)、微生物呼吸(MR)以及呼吸熵(qCO_2)均无显著影响;②总氨化速率和硝化速率对刈割处理的响应均不显著,但是刈割处理显著降低了土壤MR(P < 0.05);③氮素添加+刈割处理5-7a后,土壤总氨化和硝化速率均无显著变化;但是氮素添加+刈割处理显著增加了ANPP、土壤无机氮库和qCO_2,同时显著降低了MBC和MBC/MBN。这说明在弃耕草地适应性管理中,氮素添加可以显著提高草地生产力,但是长期的氮添加对土壤微生物氮的转化是否有利还值得我们进一步研究。
英文摘要	Agricultural restructuring and conservation priorities have led to the abandonment of farmlands in China and elsewhere. Restoration of croplands to grassland has become an important management practice during the past ten years in the grassland of Inner Mongolia in northern China. In our experimental region,grassland (steppe) represents the typical arid and semiarid regional vegetation type, which is also typical across a vast area of the Eurasian continent. Mowing of grassland is an important management practice in this area. N availability and microbial N transformation processes are key parameters for evaluation of this management practice, because these parameters greatly affect steppe productivity. However, few studies have evaluated their relative importance and interaction in old-fields in China. We investigated effects of N addition and mowing on soil N mineralization in abandoned croplands, and examined the relationships between soil N mineralization and vegetation recovery in combination with dynamic variation in soil physical -chemical properties and aboveground productivity, to provide a scientific foundation for restoration and reconstruction practices. In this study, we examined how two management practices, namely mowing and N addition, affect gross microbial N mineralization (ammonification and nitrification),microbial biomass carbon (MBC),microbial biomass nitrogen (MBN) and microbial respiration (MR) in a grass-dominated grassland in an old-field community in northern China. We began the long-term N addition and mowing experiment in 2006 in grassland that had been abandoned for ten years, near the Duolun Restoration Ecology Experimentation and Demonstration Station in Inner Mongolia, China. Four treatments were conducted, each with six replicates: control (no N addition or mowing),N addition, mowing, and N addition + mowing. N addition increased gross nitrification rate, while it had no effect on gross ammonification rate, soil MBC,MBN,microbial biomass carbon/ nitrogen ratio (MBC/MBN), MR, or microbial metabolic quotient (qCO_2). However, N addition significantly enhanced aboveground net primary productivity (ANPP) and soil inorganic nitrogen, which increased by 115% and 196% respectively compared to controls. Mowing had no significant effect on gross nitrification and ammonification rates, while it significantly reduced soil MR. After five to seven years, N addition + mowing had no significant effect on soil gross ammonification and nitrification rates. However, this treatment had significant positive effects on ANPP, NH_4~+-N + NO_3~--N, and qCO_2, while it had significant negative effects on MBC and MBC/MBN. Therefore, N addition is an effective means of increasing productivity in abandoned grasslands, but we need think carefully whether long-term N addition promotes soil microbial N transformation in abandoned grasslands. Our results highlight the need for further study of the importance of belowground C supply as a control of microbial N cycling processes. Furthermore, during the restoration of degenerated croplands, N cycling rates are stimulated, but the magnitude of this stimulation is modulated by plant community composition. Considering the significant effect of inter-annual rainfall variability on the key microbial parameters we investigated in our semi-arid study region,we emphasize that further long-term studies are needed to examine the responses of N transformation, microbial biomass, and MR to anthropogenic perturbations such as mowing and N addition.
中文关键词	氮素添加 ; 刈割 ; 草地 ; 微生物 ; 氮转化 ; 交互作用 ; 恢复
英文关键词	nitrogen addition mowing grassland microbe nitrogen transformation interaction effect restoration
语种	中文
国家	中国
收录类别	CSCD
WOS类目	ECOLOGY
WOS研究方向	Environmental Sciences & Ecology
CSCD记录号	CSCD:5540557
来源机构	中国科学院植物研究所
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/233205
作者单位	1.中国科学院植物研究所, 植被与环境变化国家重点实验室, 北京 100093, 中国; 2.山西农业大学动物科技学院, 太谷, 山西 030801, 中国
推荐引用方式 GB/T 7714	刘碧荣,王常慧,张丽华,等. 氮素添加和刈割对内蒙古弃耕草地土壤氮矿化的影响[J]. 中国科学院植物研究所,2015,35(19):6335-6343.
APA	刘碧荣,王常慧,张丽华,&董宽虎.(2015).氮素添加和刈割对内蒙古弃耕草地土壤氮矿化的影响.生态学报,35(19),6335-6343.
MLA	刘碧荣,et al."氮素添加和刈割对内蒙古弃耕草地土壤氮矿化的影响".生态学报 35.19(2015):6335-6343.