秸秆对根区土壤酶活性、无机氮及呼吸量的影响

Effect of straw on enzyme activity,inorganic nitrogen and CO_2 respiration of root zone soil

采用田间小区试验和室内土壤培养相结合的方法,研究了秸秆对根区土壤酶活性、无机氮总量和呼吸量的影响。结果表明:秸秆的加入,使土壤脲酶活性和蔗糖酶活性升高,过氧化氢酶活性与秸秆加入量达显著差异,但其活性随培养时间的延长而逐渐降低;土壤多酚氧化酶活性与其它酶活性变化规律不同,大豆田土壤多酚氧化酶活性高于玉米田多酚氧化酶活性。土壤无机氮含量随培养时间的延长而增加,其中大豆田土壤加入秸秆后,处理间没有显著差异,而玉米田土壤差异显著。各处理间土壤呼吸总量与秸秆加入量均达差异显著水平,玉米田土壤高于大豆田土壤。相关性分析表明,玉米田土壤4种酶活性与无机氮和呼吸量均呈显著相关,而大豆田土壤脲酶、多酚氧化酶活性与土壤无机氮均呈极显著相关。因此,秸秆的加入可以促进土壤微生物的活动,提高了土壤酶活性、无机氮的含量及呼吸量。

The field plot and the indoor soil incubation experiment were conducted to research the effect of straw on enzyme activity,total inorganic nitrogen and respiration of the root zone soil.Results showed that both of urease activity and invertase activity increased with straw increasing.There was a significant difference between catalase activity and amount of straw,but catalase activity gradually reduced with incubation time.Polyphenol oxidase activities had different change patterns with that of the other enzyme activities;Activities of polyphenol oxidase of soybean field soil were higher than that of corn field.The content of soil inorganic nitrogen increased with incubation time.There was no significance among treatments of straw applied to soybean field soil,but it was significantly different between treatments of corn field soil.The respirations among all the treatments were significantly different with each other,and the respirations of corn field soil were higher than that of soybean field soil.The correlation analysis showed that all the four enzyme activities of corn field soil had significant correlation with inorganic nitrogen and respirations,and the activities of urease and polyphenol oxidase of soybean field had a very significant correlation with soil inorganic nitrogen.Therefore,the addition of straw could improve soil microbial activity,and promote soil enzyme activities and soil inorganic nitrogen content.