摘要
【目的】为探明土壤盐碱化对氮素转化的影响,研究了不同盐碱化条件下氮素的矿化和硝化特征以及这些特征与土壤盐分、养分含量的关系,为盐碱化土壤养分的科学管理提供理论依据和数据支撑。【方法】随机采集了30个不同盐碱化程度的稻田土壤(0—20 cm)样品,根据盐碱化程度将采集的土壤样品划分为轻度(含盐量0.1%~0.3%,碱化度5%~15%)、中度(含盐量0.3%~0.5%,碱化度15%~30%)和重度(含盐量0.5%~0.7%,碱化度30%~45%)盐碱土3类,每个类别中依据最小归类样品数选取盐碱化程度接近的3个土样作为3次重复,进行氮素矿化和硝化室内培养试验(25℃,24 h光照)。于培养的第0、3、6、9、15、21天取样测定土壤铵态氮、硝态氮含量及脲酶和碱性蛋白酶活性。通过相关性分析研究土壤各指标与氮素矿化、硝化过程间的相关关系,采用逐步回归分析筛选影响氮素矿化和硝化过程的主要因子。【结果】随着土壤盐碱化程度的加剧,氮素矿化和硝化作用显著下降(P<0.05)。与轻度盐碱土相比,中度和重度盐碱土的氮素最大净矿化速率分别低12.7%和29.8%,累积矿化氮量分别低15.7%和25.2%,最大净硝化速率分别低15.4%和23.1%,累积硝化氮量分别低15.4%和23.1%,最大脲酶活性分别低16.0%和34.8%,最大碱性蛋白酶活性分别低6.0%和15.6%。逐步回归分析表明,土壤电导率(EC)、pH、CO_(3)^(2-)、Na^(+)、全氮和有机质是影响土壤氮素矿化作用的主要因子,EC、pH、CO_(3)^(2-)、Na^(+)和有机质是影响土壤氮素硝化作用的主要因子。【结论】随着土壤盐碱化程度的增加,土壤氮素净矿化速率、净硝化速率、累积矿化氮量、累积硝化氮量、脲酶和碱性蛋白酶活性不断下降,土壤盐碱化显著抑制了氮素的矿化和硝化作用。
【Objectives】Nitrogen mineralization and nitrification under different saline conditions and the relationships between the two processes and soil salinity and nutrient content were studied to clarify the effect of soil salinization on nitrogen transformation,to provide a theoretical basis and data support for the scientific management of soil nutrients.【Methods】Thirty paddy soil samples from at 0-20 cm depth with different degrees of salinization were randomly collected.According to the degree of salinization,the collected soil samples were divided into light(salt 0.1%-0.3%,exchange sodium percentage 5%-15%),moderate(salt 0.3%-0.5%,exchange sodium percentage 15%-30%)and severe(salt 0.5%-0.7%,exchange sodium percentage 30%-45%)saline-sodic soils.The incubation experiments for N mineralization and nitrification were carried out in the laboratory(25℃,24 hours illumination).The NH_(4)^(+)-N and NO_(3)^(-)-N contents and urease and alkaline protease activities were measured on 0,3,6,9,15 and 21 days of incubation.The correlation between soil indexes and nitrogen mineralization and nitrification was studied by correlation analysis.The main influencing factors of soil nitrogen mineralization and nitrification were screened by stepwise regression analysis.【Results】With the intensification of soil salinity,nitrogen mineralization and nitrification decreased significantly(P<0.05).The maximum net mineralization rate,cumulative mineralization,maximum net nitrification rate,cumulative nitrification in moderate and severe saline-sodic soils were 12.7%and 29.8%,15.7%and 25.2%,15.4%and 23.1%,15.4%and 23.1%lower than those of light saline-sodic soils,respectively(P<0.05).The maximum activities of urease and alkaline protease were 16.0%and 34.8%,6.0%and 15.6%lower than those of light saline�sodic soils,respectively.Stepwise regression analysis showed that soil electrical conductivity(EC),pH,CO32-,Na+,total N and organic matter contents were the main factors affecting soil nitrogen mineralization,and EC,pH,CO32-,Na+and organic matter contents were the main factors affecting soil nitrogen nitrification.【Conclusions】With the increase in soil salinization,soil net nitrogen mineralization rate,net nitrification rate,cumulative mineralized nitrogen,cumulative nitrification nitrogen,urease and alkaline protease activities decrease,and soil salinization significantly inhibits nitrogen mineralization and nitrification.
作者
杨易
黄立华
肖扬
黄金鑫
刘伯顺
杨靖民
YANG Yi;HUANG Li-hua;XIAO Yang;HUANG Jin-xin;LIU Bai-shun;YANG Jing-min(College of Resources and Environmental,Jilin Agricultural University,Changchun,Jilin 130118,China;Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun,Jilin 130102,China;Jilin Da’an Farmland Ecosystem National Observation and Research Station,Da’an,Jilin 131317,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2022年第10期1816-1827,共12页
Journal of Plant Nutrition and Fertilizers
基金
黑土地保护与利用科技创新工程专项(XDA28110103)
国家自然科学基金面上项目(41977148)
吉林省科技发展项目(20220508110RC)。
关键词
苏打盐碱土
氮素矿化
氮素硝化
土壤酶活性
影响因素
saline-sodic soil
nitrogen mineralization
nitrogen nitrification
soil enzyme activities
influencing factor