摘要
为探究冻融作用下添加秸秆对农田土壤氮动态的影响,采用室内模拟试验研究了冻融循环、添加秸秆、土壤湿度以及三者间的交叉作用对土壤有效氮含量和氮矿化速率的影响。结果表明,冻融能显著增加土壤铵氮和无机氮含量,增幅分别为98%和33%,但对硝氮含量影响不显著;冻融作用下,相较未加秸秆的对照,添加秸秆后土壤铵氮含量显著减少了62%,而硝氮含量变化不显著;不同水分处理下,60%和100%水分处理下的铵氮含量和氨化速率显著高于20%的水分处理,而其硝氮含量和硝化速率则显著低于20%的水分处理,60%和100%的水分处理间各指标差异不显著;冻融循环次数显著影响土壤氮动态指标,其中,在第1次冻融循环后,土壤氨化和净氮矿化速率最高,此后显著降低,在第4次冻融循环后,趋于稳定;不同处理下,硝化速率随着冻融循环次数的增加呈现出不同的变化趋势。方差分离结果表明,添加秸秆与水分处理对无机氮含量的方差解释量较大,分别为35.1%和21.2%;冻融循环次数对氨化和净氮矿化的方差解释量较大,分别为56.0%和43.5%;三因素间的交叉作用对土壤硝化作用的方差解释量最大。冻融循环作用对农田土壤氮矿化过程有着重要影响,且影响程度受秸秆添加和土壤水分含量的影响。
To examine the effects of freeze-thaw cycles and straw addition on soil nitrogen(N) dynamics, the laboratory experiment was used to determine the effects of straw addition, freeze-thaw cycles, soil moisture treatments and their interaction effects on soil available N contents and mineralization rates. The results showed that both freezing and thawing significantly increased soil ammonium(NH+4) and total inorganic N(TIN) by 98% and 33%, respectively. Relative to the control without straw, straw addition significantly reduced soil NH+4by 62% under freeze-thaw cycle conditions, and exerted no significant effect on soil nitrate(NO-3). Under different water treatments, soil NH+4and ammoniation rates under the 60% and 100% water treatments were significantly higher than those under the 20% water treatment, while soil NO-3and nitrification rates were significantly lower than those under the 20% water treatment. Additionally, there was no significant difference between 60% and 100% water treatments. The number of freeze-thaw cycles significantly affected the soil N dynamics. After the first freeze-thaw cycle, the soil ammoniation and net N mineralization rates were the highest, then significantly decreased, and lastly remained stable after the fourth freeze-thaw cycle. Under different water treatments, the nitrification rates showed different trends with the increase of freeze-thaw times. The results of variance partitioning showed that soil water treatment and straw addition explained 35.1% and 21.2% of the total variance in soil TIN, respectively. The number of freeze-thaw cycle respectively explained 56.0% and 43.5% of the total variance in soil ammoniation and net nitrogen mineralization rates. The interaction effect of the three factors explained the largest part of the variance in soil nitrification rate. This study indicates that freeze-thaw cycles could have an important impact on the process of soil nitrogen mineralization, and the influence degree is affected by straw addition and soil moisture.
作者
孔健健
李梦
齐楠
杨扬
刘晓晴
王凯泽
KONG Jianjian;LI Meng;QI Nan;YANG Yang;LIU Xiaoqing;WANG Kaize(College of Life Science,Shenyang Normal University,Shenyang 110034,China;Department of Science and Technology,Shenyang Normal University,Shenyang 110034,China)
出处
《沈阳师范大学学报（自然科学版）》
CAS
2022年第6期527-534,共8页
Journal of Shenyang Normal University:Natural Science Edition
基金
国家重点研发计划项目(2017YFA0604403)
辽宁省教育厅重点项目(LNKZ0994)。
关键词
冻融循环
秸秆还田
无机氮
氮矿化速率
freeze-thaw cycles
straw return
inorganic nitrogen
nitrogen mineralization rates
