冻融对农田黑土可溶性氮库、氮转化过程及酶活性的影响  

Effects of freeze-thaw on dissolved nitrogen pool,nitrogen transformation processes and enzyme activity in farm-land black soil

作　　者：刘艳[1] 隋世江[1] 包红静[1] 邢月华[1] 隽英华[1] LIU Yan;SUI Shi-jiang;BAO Hong-jing;XING Yue-hua;JUAN Ying-hua(Institute of Plant Nutrition and Environmental Resources,Liaoning Academy of Agricultural Sciences,Shenyang Liaoning 110161)

机构地区：[1]辽宁省农业科学院植物营养与环境资源研究所,辽宁沈阳110161

出　　处：《中国土壤与肥料》2023年第4期40-46,共7页Soil and Fertilizer Sciences in China

基　　金：沈阳市科技计划项目(21-109-3-01)。

摘　　要：探讨非生长季土壤可溶性氮库、氮素转化过程及氮代谢关键酶活性如何响应冻融交替,对于支撑土壤肥力保持和农田养分管理具有重要意义。以农田黑土为研究对象,采用室内模拟培养试验分析冻融循环作用下土壤可溶性氮库组分[可溶性无机氮(NH_(4)^(+)-N+NO_(3)^(-)-N,DIN)、可溶性有机氮(DON)、可溶性全氮(DTN)]、净氮矿化速率(NNMR)、微生物量氮(MBN)和氮代谢关键酶活性的变化行为,阐明冻融循环对土壤可溶性氮转化过程的影响机制。冻融循环对农田黑土可溶性氮库、氮素转化过程、MBN及氮代谢关键酶活性影响显著(P<0.05)。随着循环次数增加,冻融土壤NH_(4)^(+)-N、NO_(3)^(-)-N、DIN和NNMR均显著降低,而DON、DTN和MBN均先升高后降低,在循环次数6时达到最大值,较对照土壤分别增加了4.65%、5.43%和18.38%。随着循环次数增加,冻融土壤蛋白酶活性显著增加,硝酸还原酶活性先增加后降低,以循环次数6的最大[1.19 NO_(2)^(-)-Nµg/(g·24 h)]。可见,适宜的冻融循环(1~6)能够显著促进非生长季农田黑土氮素转化,有利于土壤有效氮累积。Exploring how soil dissolved nitrogen pool fractions,nitrogen transformation processes and key enzyme activities of nitrogen metabolism respond to freezing-thawing cycle during non-growing season is important for supporting soil fertility sustainment and farmland nutriment management.With the farmland black soil as the research object,a laboratory simulation experiment was conducted to analyze the changes of soil dissolved nitrogen pool fractions[dissolved inorganic nitrogen(NH_(4)^(+)-N+NO_(3)^(-)-N,DIN),dissolved organic nitrogen(DON),dissolved total nitrogen(DTN)],net nitrogen mineralization rate(NNMR),microbial biomass nitrogen(MBN)and key enzyme activities of nitrogen metabolism under the freezing-thawing cycle for clarifying mechanisms of the effects of freezing-thawing cycle on soil dissolved nitrogen transformation.Freezing-thawing cycle had significant influence on dissolved nitrogen pool fractions,nitrogen transformation processes,MBN and key enzyme activities of nitrogen metabolism in the farmland black soil(P<0.05).The contents of NH_(4)^(+)-N、NO_(3)^(-)-N、DIN and NNMR decreased significantly in response to increasing cycles of freeze-thaw,but the contents of DON、DTN and MBN first increased then decreased,reaching the highest values at cycle number 6 with increment of 4.65%,5.43%and 18.38%,compared with the control check,respectively.With the increasing of freezing-thawing cycle,soil protease activity significantly increased,and nitrate reductase activity first increased then decreased,reaching the highest values at cycle number 6 with 1.19 NO_(2)^(-)-Nµg/(g·24 h).Therefore,it is preliminarily concluded that the reasonable freezing-thawing cycle number(1~6)could significantly promote nitrogen transformation of farmland black soil during non-growing season,and was beneficial to the accumulation of soil available nitrogen.

关 键 词：冻融 可溶性氮库 净氮矿化速率 微生物量氮 蛋白酶 硝酸还原酶 

分 类 号：S153.6[农业科学—土壤学]