水氮耦合对西北旱区覆膜农田土壤有机碳、氮矿化的影响  

Effects of Water-Nitrogen Coupling on the Mineralization of Organic Carbon and Nitrogen for Mulched Farmland Soils in the Arid Regions of Northwest China

作　　者：赵彤彤 谷晓博 谭川东 延廷霖 李晓雁 常甜 杜娅丹 ZHAO TongTong;GU XiaoBo;TAN ChuanDong;YAN TingLin;LI XiaoYan;CHANG Tian;DU YaDan(College of Water Resources and Architectural Engineering,Northwest A&F University/Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Area of Ministry of Education,Yangling 712100,Shaanxi)

机构地区：[1]西北农林科技大学水利与建筑工程学院/西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《中国农业科学》2025年第5期929-942,共14页Scientia Agricultura Sinica

基　　金：国家重点研发计划(2021YFD1900700);陕西省重点研发计划(2023-YBNY-040)。

摘　　要：【目的】明确灌溉和施氮对土壤肥力的影响,探明不同水氮条件下覆膜农田土壤有机碳、氮矿化特征及其影响因素,为西北旱区覆膜农田水氮调控提供理论依据。【方法】在连续5年覆膜施氮冬小麦-夏玉米田间定位试验田块,采集施氮量为0(N0)、180 kg·hm^(-2)(N1)和360 kg·hm^(-2)(N2)3个施氮水平覆膜小区的土壤样品,并分别设置40%田间持水量(W0)、60%田间持水量(W1)和100%田间持水量(W2)3个土壤水分梯度进行室内有机碳、氮矿化培养试验,分析不同水氮条件对覆膜农田土壤有机碳、氮矿化的影响特征。【结果】增加土壤含水量显著提高了土壤累积碳矿化量(C_(min))、碳矿化速率、土壤累积净氮矿化量(N_(min))、氮矿化速率和潜在矿化氮(N_(p))。C_(min)、N_(min)和N_(p)均随施氮量的增加呈先增后降的趋势。培养结束后,N1W1处理C_(min)最高(1781.00 mg·kg^(-1)),比其他处理显著提高8.8%—51.8%,且其N_(min)(29.52 mg·kg^(-1))、潜在矿化碳(5883.79 mg·kg^(-1))和N_(p)(30.74 mg·kg^(-1))也维持在相对较高水平。随机森林算法表明,土壤微生物碳(MBC)、土壤微生物氮、溶解性有机碳、有机碳和总溶解氮是影响C_(min)和N_(min)的重要因子。MBC随土壤水分增加呈先增后降趋势,W1下MBC含量分别比W0和W2处理显著增加60.1%—340.0%和3.1%—6.7%。结构方程表明,土壤水分对土壤碳矿化有直接正效应(0.70),对土壤氮矿化有间接正效应(0.55);施氮对土壤氮矿化有直接正效应(0.90),对土壤碳矿化有间接负效应(0.24)。【结论】从土壤碳、氮矿化角度出发,60%田间持水量和施氮肥180 kg·hm^(-2)作为西北旱区覆膜农田适宜的水、氮推荐量。【Objective】This study aimed to clarify the effects of irrigation and nitrogen application on soil fertility,to explore the characteristics of organic carbon and nitrogen mineralization and their influencing factors in mulched farmland soils under different water and nitrogen conditions,so as to provide the theoretical basis for water and nitrogen control measures for mulched farmland crops in the Northwest of China.【Method】In this study,on the basis of five consecutive years of field trials of winter wheat-summer maize with nitrogen application in mulching,the soil samples were collected under three nitrogen application levels of 0(N0),180 kg·hm^(-2)(N1)and 360 kg·hm^(-2)(N2),and three soil moisture gradients,namely,40%of the field holding capacity(W0),60%of the field holding capacity(W1),and 100%of the field holding capacity(W2),were set up for indoor organic carbon and nitrogen mineralization.Then,the effect of water-nitrogen coupling on soil organic carbon and nitrogen mineralisation in mulched farmland were analyzed.【Result】Increasing water content significantly increased the cumulative soil carbon mineralization(C_(min)),carbon mineralization rate,cumulative net soil nitrogen mineralization(N_(min)),nitrogen mineralization rate,and potential mineralized nitrogen(N_(p)).C_(min),N_(min)and N_(p)all showed a tendency to increase and then decrease with increasing nitrogen application.At the end of incubation,C_(min)was the highest under N1W1 treatment(1781.00 mg·kg^(-1)),which was significantly higher than that under other treatments(N0W0,N0W1,N0W2,N1W0,N1W2,N2W0,N2W1,N2W2)by 8.8%to 51.8%,respectively,and its N_(min)was also maintained at a relatively high level(29.52 mg·kg^(-1)),while the potential mineralized carbon(5883.79 mg·kg^(-1))and N_(p)(30.74 mg·kg^(-1))were also maintained at a relatively high level.The random forest algorithm indicated that soil microbial carbon(MBC),soil microbial nitrogen,dissolved organic carbon,organic carbon,and total dissolved nitrogen were the important facto

关 键 词：施氮量 土壤水分 碳矿化 净氮矿化 矿化动力学 西北旱区 

分 类 号：S15[农业科学—土壤学]