陇中地区多年种植苜蓿后不同后茬作物的土壤有机氮特征  

Characterization of soil organic nitrogen component in different succeeding crops of lucerne on the Loess Plateau of central Gansu

作　　者：马欣 谢泽宇 罗珠珠[1,2] 李玲玲 牛伊宁 蔡立群 谢军红[2] 张耀全 MA Xin;XIE Ze-yu;LUO Zhu-zhu;LI Ling-ling;NIU Yi-ning;CAI Li-qun;XIE Jun-hong;ZHANG Yaoquan(College of Resources and Environmental Sciences,Gansu Agricultural University,Lanzhou Gansu 730070;Gansu Provincial Key Laboratory of Arid Land Crop Science,Lanzhou Gansu 730070)

机构地区：[1]甘肃农业大学资源与环境学院,甘肃兰州730070 [2]甘肃省干旱生境作物学省部共建国家重点实验室,甘肃兰州730070

出　　处：《中国土壤与肥料》2020年第2期17-23,共7页Soil and Fertilizer Sciences in China

基　　金：国家自然科学基金项目(31860364,41461067,31171513);甘肃省科技计划项目(18JR3RA175)。

摘　　要：依托2012年设置在陇中黄土高原雨养农业区苜蓿后茬作物的长期定位试验,探讨6种不同后茬作物[苜蓿连作(LC)、苜蓿-休闲(LF)、苜蓿-休闲-小麦(LFW)、苜蓿-休闲-玉米(LFC)、苜蓿-马铃薯(LP)和苜蓿-谷子(LMi)]对土壤有机氮组分的影响。结果表明,不同后茬作物土壤全氮含量随着土层加深逐渐降低,0~10 cm土层LC土壤全氮含量最高,与LC相比,LMi、LP、LFW、LFC、LF全氮含量分别降低21.62%、14.27%、18.98%、13.41%、6.15%。土壤微生物量氮与土壤全氮含量变化趋势一致。不同后茬作物酸解态氮在土壤全氮中占主体,酸解有机氮中酸解未知态氮含量最高,氨基酸态氮次之,氨基糖态氮含量最低。各处理0~10cm土层酸解氮组分差异显著,与苜蓿连作相比,其余处理酸解总氮含量有所降低,降幅为11.90%~35.98%,氨基酸态氮含量降幅为10.29%~37.83%,酸解铵态氮含量降幅为24.11%~39.73%,LF和LP处理酸解未知态氮含量分别提高10.76%、3.39%,LMi、LFC、LFW处理酸解未知态氮含量分别降低9.34%、43.62%、65.18%。氨基酸态氮与土壤全氮、微生物量氮呈显著正相关关系。因此,在黄土高原雨养农业区推行苜蓿连作种植模式可以保持土壤有机氮的有效态组分,有利于本地区农业的可持续发展。A long-term rainfed field experiment comparing the effects of different succeeding crops of lucerne on soil organic nitrogen composition was conducted on the Loess Plateau in 2012.Six succeeding crops of lucerne [lucerne continuous cropping(LC),lucerne-fallow(LF),lucerne-fallow-wheat(LFW),lucerne-fallow-corn(LFC),lucerne-potato(LP)and lucerne-millet(LMi)] were compared.The results showed that the soil total nitrogen content of different succeeding crops of lucerne gradually decreased with the deepening of the soil layer,In the 0 ~ 10 cm soil layer,LC had the highest total nitrogen content among treatments.Compared with LC,the total nitrogen contents of LMi,LP,LFW,LFC and LF were decreased by 21.62%,14.27%,18.98%,13.41% and 6.15% respectively.The soil microbial biomass nitrogen was consistent with the trend of soil total nitrogen content.Among all the soil organic nitrogen forms under different succeeding crops of lucerne,acid hydrolysable nitrogen was dominant in soil total nitrogen.The content of hydrolysable unidentified N in acid hydrolysable organic nitrogen was the highest,followed by amino acid nitrogen and amino sugar nitrogen.The difference of acid hydrolysable nitrogen components in 0 ~ 10 cm soil layer was significant.Compared with the lucerne continuous cropping,the total nitrogen content of the remaining acidification was reduced,the decline was 11.90% to 35.98%.The content of amino acid nitrogen decreased by 10.29% to 37.83%,the content of acid-decomposed ammonia nitrogen decreased by 24.11% to 39.73%,and the content of hydrolysable unidentified N in acid treatment of LF and LP increased by 10.76% and 3.39% respectively.The hydrolysable unidentified N content of LMi,LFC and LFW treatments decreased by 9.34%,43.62% and 65.18%,respectively.Amino acid nitrogen was positively correlated with soil total nitrogen and microbial biomass nitrogen.Therefore,the implementation of the continuous cropping system in the rain-fed agriculture area of the Loess Plateau can maintain the effective composition of soil o

关 键 词：苜蓿 有机氮组分 后茬作物 

分 类 号：S153.6[农业科学—土壤学]