不同形态氮素添加下三江源区高寒草甸草场氮素分配与利用  

Nitrogen allocation and utilization in alpine meadows of the Sanjiangyuan region under exogenous additions of different nitrogen forms

作　　者：向雪梅 德科加[1] 张琳[1] 冯廷旭 林伟山[1] 钱诗祎 魏希杰[1] 王伟[1] 徐成体[1] 耿晓平 XIANG Xue-mei;DE Ke-jia;ZHANG Lin;FENG Ting-xu;LIN Wei-shan;QIAN Shi-yi;WEI Xi-jie;WANG Wei;XU Cheng-ti;GENG Xiao-ping(Qinghai University/Qinghai Academy of Animal Husbandry and Veterinary Science,Xining,Qinghai 810016,China;Chenduo Bureau of Meteorology,Chenduo,Qinghai 815199,China)

机构地区：[1]青海大学/青海省畜牧兽医科学院,青海西宁810016 [2]青海省称多县气象局,青海称多815199

出　　处：《植物营养与肥料学报》2023年第3期511-520,共10页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金项目(31860678);青海三江源草地生态系统国家野外科学观测研究站称多子站建设项目(K9922050)。

摘　　要：【目的】研究三江源区高寒草甸牧草对不同形态氮素的吸收利用和残留氮素在土壤中的去向及分配,以期为制定三江源区高寒草甸草场养分科学添加方案提供理论依据。【方法】于2020年6月至2021年9月,在青海省称多县高寒草甸试验站开展^(15)N田间微区示踪试验,试验设置3个不同氮素形态处理,分别为(^(15)NH_(4))_(2)SO_(4)、Ca(15NO3)2、CO(^(15)NH_(2))_(2),各处理的氮素施用量均为N 300 kg/hm^(2)。分析了施肥当年和次年不同形态氮素在高寒草甸牧草地上部、地下部中的含量,及在0—15、15—30 cm土层土壤中的去向及分配。【结果】1)在施肥当年,与Ca(^(15)NO_(3))_(2)、(^(15)NH_(4))_(2)SO_(4)处理相比,CO(^(15)NH2)2处理下牧草地上部氮素吸收量分别显著增加了276.4%、48.1%,地下部分别显著增加了360.3%、129.2%;0—15 cm土层中的氮素残留量分别增加了275.6%、78.4%,15—30 cm土层分别增加了240.1%、115.6%(P<0.05)。2)在施肥次年,与Ca(^(15)NO_(3))_(2)、(^(15)NH_(4))_(2)SO_(4)处理相比,CO(15NH2)2处理牧草地上部分氮素吸收量分别显著增加了206.9%、66.1%,牧草地下部分显著增加了473.2%、234.4%;0—15 cm土层中氮素残留量分别显著增加了635.6%、129.5%,15—30 cm土层分别显著增加了22.5%、188.2%(P<0.05)。3)在施氮当年,(^(15)NH_(4))_(2)SO_(4)和Ca(^(15)NO_(3))_(2)处理氮素去向表现为:^(15)N损失量>^(15)N土壤残留量>^(15)N植物吸收量,而CO(^(15)NH_(2))_(2)处理为:^(15)N土壤残留量>^(15)N植物吸收量>^(15)N损失量;在施氮次年(^(15)NH_(4))_(2)SO_(4)和Ca(^(15)NO_(3))_(2)处理的氮素去向为:^(15)N损失量>^(15)N植物吸收量>15N土壤残留量,而CO(^(15)NH_(2))_(2)处理为:^(15)N植物吸收量>^(15)N损失量>^(15)N土壤残留量。【结论】外源添加CO(^(15)NH_(2))_(2)能保证较高的氮素吸收率、较低的损失率,且残留氮素能发挥较好的后效作用,因此酰胺态氮为三江源区高寒草甸草场优选的氮素�【Objective】We studied the absorption and utilization of different N forms by alpine meadow plants,and the fate of residual N in the soil to provide a theoretical basis for efficient and environmentally friendly fertilization of alpine meadows in the Sanjiangyuan area.【Methods】A field microplot experiment was carried out using the^(15)N tracer method at the Alpine Meadow Experimental Station in Chengduo County,Qinghai Province,from June 2020 to September 2021.The three N sources tested were(^(15)NH_(4))_(2)SO_(4),Ca(^(15)NO_(3))_(2),and CO(^(15)NH_(2))_(2),applied at N 300 kg/hm^(2)in early 2020.The N content and uptake in the above-and under-ground parts of forages were measured,and the N content in the 0–15 cm and 15–40 cm soil layers was analyzed in 2020 and 2021.【Results】1)In the same year of N application,compared with Ca(^(15)NO_(3))_(2)and(^(15)NH_(4))_(2)SO_(4),CO(^(15)NH_(2))_(2)increased N absorption by 276.4%and 48.1%in the aboveground part,360.3%and 129.2%in the underground part of forages,275.6%and 78.4%for the N residual amount in the 0-15 cm soil layer,and 240.1%and 115.6%in the 15-30 cm soil layer(P<0.05).2)In the following year of N application,compared with Ca(^(15)NO_(3))_(2)and(^(15)NH4)_(2)SO_(4),CO(^(15)NH_(2))_(2)increased the N absorption in the aboveground part by 206.9%and 66.1%,473.2%and 234.4%in the underground part of forages,635.6%and 129.5%for residual N amount in 0-15 cm soil layer,and 22.5%and 188.2%in 15-30 cm soil layer(P<0.05).3)In the same year of N application,the fate of(^(15)NH_(4))_(2)SO_(4)and Ca(^(15)NO3)2 were in the order^(15)N loss>^(15)N soil residue>^(15)N plant uptake and^(15)N soil residue>^(15)N plant uptake>^(15)N loss for CO(^(15)NH_(2))_(2).In the following year of N application,the fate of(^(15)NH_(4))_(2)SO_(4)and Ca(^(15)NO_(3))_(2)were:^(15)N loss>^(15)N plant absorption>^(15)N soil residue and^(15)N plant absorption>^(15)N loss>^(15)N soil residue for CO(^(15)NH_(2))_(2).【Conclusion】CO(^(15)NH_(2))_(2)promotes a high nitrogen uptake rat

关 键 词：氮素形态 高寒草甸 氮素去向 ^(15)N示踪技术 

分 类 号：S812[农业科学—草业科学]