天山北坡典型草地施肥阈值及不确定性分析  

Nitrogen fertilizer threshold and uncertainty analysis of typical grassland on the northern slopes of Tianshan Mountains

作　　者：韩其飞 尹龙[1] 李超凡 张润钢 王文彪 崔正南 HAN Qi-fei;YIN Long;LI Chao-fan;ZHANG Run-gang;WANG Wen-biao;CUI Zheng-nan(School of Geographical Sciences,Nanjing University of Information Science&Technology,Nanjing 210044,China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanjing 210044,China;Elion Resources Group Co.,Ltd.,Beijing 100020,China)

机构地区：[1]南京信息工程大学地理科学学院,江苏南京210044 [2]南京信息工程大学气象灾害预报预警与评估协同创新中心,江苏南京210044 [3]亿利资源集团有限公司,北京100020

出　　处：《草业学报》2024年第1期19-32,共14页Acta Prataculturae Sinica

基　　金：国家自然科学基金(42271493,42177436)资助。

摘　　要：在全球气候变化的背景下,干旱半干旱区草地作为陆地生态系统中重要且非常脆弱的组分之一,显现出一系列生态问题。探究气候变化及人类活动对于该区草地生态系统净初级生产力(NPP)的影响,对于合理利用自然资源,保持农牧业可持续发展具有重要的意义。施肥作为促进作物生长的一种方式,合理施肥也可以提高退化草地的NPP。基于此,本研究拟以天山北坡沿海拔梯度分布的4种草地类型:高山草甸(AM)、中山森林草甸(MMFM)、低山干草原(LMDG)和平原荒漠草原(PDG)为研究对象,基于反硝化-分解模型(DNDC)分析该区典型草地生态系统净初级生产力对施加不同氮肥的响应,并揭示施肥阈值及最优施肥方式。结果表明:1)适度氮肥添加促进了各个类型草地生态系统NPP的增长,但草地NPP对施肥量的响应存在阈值,且不存在适用于4种草地类型的统一最优施肥方式。LMDG草地生态系统对施氮肥的响应最敏感。2)PDG草地NPP达到最大的施肥方式为一年分两次施加100 kg·hm^(-2)硝酸盐,NPP的最大值为68.72 g C·m^(-2)·a^(-1)。LMDG草地NPP最大的施肥方式为一年分两次施加尿素260 kg·hm^(-2),NPP的最大值为263.28 g C·m^(-2)·a^(-1)。MMFM草地生态系统达到NPP最大的施肥方式为一年一次施尿素80 kg·hm^(-2),NPP的最大值为171.22 g C·m^(-2)·a^(-1)。无水氨作为在AM草地中反应最好的氮肥,以最小的施肥量(60 kg·hm^(-2))达到了NPP的最大值(114.62 g C·m^(-2)·a^(-1))。3)通过蒙特卡洛不确定分析的结果显示,施肥时间对PDG和LMDG的影响更为明显,施肥量波动对LMDG和MMFM的影响较其他两种草地更为明显。In the context of climate change and increasing human activities,a series of ecological problems have emerged in arid and semi-arid regions as one of the important and very vulnerable components of the terrestrial ecosystem.Exploring the impact of climate change and human activities on the net primary productivity(NPP)is of great significance for the rational use of natural resources and the sustainable development of agriculture and animal husbandry.Nitrogen fertilization is a way to promote increased NPP and appropriate fertilization can improve the NPP of grassland.To further explore the potential use of N fertilization,this study investigated four grassland types,alpine meadow(AM),mid-mountain forest meadow(MMFM),low mountain dry grassland(LMDG)and plain desert grassland(PDG),distributed along the altitude gradient on the northern slope of Tianshan Mountains,and employed a denitrification-decomposition model to analyze the NPP responses of the typical grassland ecosystem in this region to the application of different nitrogen fertilizers,and reveal the nitrogen fertilizer threshold and the optimal fertilization strategy.It was found that:1)Appropriate nitrogen addition led to an increase in NPP of all types of grassland ecosystems,but there was a threshold value for the response of grassland NPP to fertilizer application,and different types of grassland NPP had different threshold values.There was no unified optimal fertilization method applicable to the four types of grassland.LMDG grassland ecosystem is the most sensitive to nitrogen application.2)The maximum NPP in PDG grassland was achieved by applying 100 kg·ha^(-1) nitrate twice a year,and the maximum NPP was 68.72 g C·m^(-2)·yr^(-1).The maximum NPP fertilization strategy in LMDG grassland is 260 kg·ha^(-1) of urea applied twice a year,and the maximum NPP value is 263.28 g C·m^(-2)·yr^(-1).The maximum NPP of MMFM was achieved by applying 80 kg·ha^(-1) of urea once a year,and the maximum NPP is 171.22 g C·m^(-2)·yr^(-1).In AM grassland,anhydrous

关 键 词：天山北坡 DNDC模型 施肥阈值 净初级生产力 蒙特卡洛分析 

分 类 号：S812[农业科学—草业科学]