论文部分内容阅读
通过室内模拟试验(2013年7月23日~8月15日),研究不同含水量(20%,35%,60%)条件对东北黑土区土壤氮素转化及土壤酶活性的影响,初步探讨了其作用机制。结果表明:随着培养时间的增加,不同含水量的铵态氮含量呈波动性变化,最后呈下降趋势;硝态氮含量随着时间的增加一直呈下降趋势,35%及60%含水量的黑土铵态氮和硝态氮含量在相同培养时间高于20%含水量的黑土。各含水量处理组氨化速率、矿化速率、硝化速率随着培养时间的增加均逐渐下降,说明土壤中可被转化的有机氮含量逐渐降低,60%含水量的黑土净矿化速率和净硝化速率变化幅度最大,分别从1.518 g kg-1d-1、1.376 g kg-1d-1下降到0.009 g kg-1d-1,0.007 g kg-1d-1;除了35%含水量处理组在24 h内的氨化速率高于其他两组含水量氨化速率外,整个培养期间的氮素转化速率均表现为60%含水量>35%含水量>20%含水量。对土壤酶活性的研究表明:在培养初期(前2 d),20%含水量土壤脲酶活性逐渐增加,35%和60%含水量土壤脲酶活性先增加后下降,随后脲酶活性趋于稳定,直到第13 d开始略有下降,总体来看,2 d后不同含水量对脲酶活性的影响变化不显著;而转化酶活性呈波动性变化,整个培养周期,35%含水量的转化酶活性始终高于60%含水量处理组,而20%含水量的转化酶活性在其他两组含水量的转化酶活性上下波动。研究表明含水量对黑土氮素转化影响显著,硝化、矿化、反硝化作用及土壤中微生物活性的变化是氮素转化及酶活性变化的主要原因。
The effects of different water content (20%, 35%, 60%) on soil nitrogen transformation and soil enzyme activities in the black soil region of Northeast China were studied by laboratory simulation (from July 23 to August 15, 2013) The mechanism of action. The results showed that with the increase of incubation time, the content of ammonium nitrogen in different water contents fluctuated and finally decreased. The content of nitrate nitrogen decreased with the increase of time, while the content of 35% and 60% water content Black soil ammonium nitrogen and nitrate nitrogen content in the same culture time is higher than 20% moisture content of black soil. The ammonification rate, mineralization rate and nitrification rate decreased gradually with the increase of incubation time in each water content treatment group, indicating that the content of organic nitrogen that can be transformed in soil decreased gradually. The net mineralization rate of black soil with 60% The rate of change of nitrification ranged from 1.518 g kg-1d-1 and from 1.3776 g kg-1d-1 to 0.009 g kg-1d-1 and 0.007 g kg-1d-1, respectively. h, the rate of ammonification was higher than that of the other two groups. The nitrogen conversion rate of all the cultivars was 60% water content> 35% water content> 20% water content. The results showed that the activity of urease in soil increased gradually at 20% water content, while the urease activity increased at first and then decreased at 35% and 60% water content, then the urease activity tended to be stable until On the whole, the activity of urease did not change significantly after 2 d, while the invertase activity showed a fluctuant change. The activity of invertase at 35% water content was always high throughout the incubation period At 60% water content, the invertase activity of 20% water content fluctuated between the two other water invertase activities. The results showed that water content had a significant effect on nitrogen conversion in black soil. Nitrification, mineralization, denitrification and changes in soil microbial activity were the main reasons for nitrogen transformation and enzyme activity changes.