黑土微生物活力对不同养分的响应

The response of soil microbial activity to different nutrition conditions

土壤呼吸是土壤有机碳分解的主要生物化学过程,可反映土壤有机质的分解程度及有效养分供给水平,可用于评价土壤微生物活力状况。通过设置8个养分处理,对黑土进行41d的室内好气培养,考查了黑土微生物活力对不同养分响应的规律。结果表明,单加N或P以及NP组合均不能提高黑土微生物活力;单加葡萄糖能够使土壤呼吸释放的CO2累积量达到对照的10倍以上,使黑土微生物活力显著提高。在可利用碳底物充足的条件下,N的加入能够显著提高黑土微生物活力,土壤呼吸释放出的CO2累积量达到对照的13倍以上,显著促进土壤有机质中无机养分的释放,CN交互作用显著;在C和N养分都充足的条件下,P的加入才能够对黑土微生物产生激发效应。不同养分状况下,黑土微生物活力达到峰值的时间不同,表现为,CNP(C+N+P)处理土壤呼吸强度在第3d达到最高值,CN(C+N)处理在第5天达到最高值,单加C和CP(C+P)处理,在15d左右达到最高值。

Soil respiration is a main biochemistry process for the decomposition of the soil organic carbon. It can reflect the extent of the decomposition of soil organic matter and the level of nutrition supplying. It also can be used as an index for the evaluation for the total activity of the microorganisms. We set eight treatments and incubated the soil for 41 days in the laboratory. The response of soil respiration to different nutrient status is studied. The results showed that the addition of nitrogen （N）or phosphorus （P） only cannot raise the soil respiration rate, so is the NP treatment; the cumulative amount of CO2 under the C （glucose） treatment was almost 10 times that of the control. The addition of nitrogen （N） can raise soil respiration rate significantly when the labile carbon substrate is sufficient; the carbon and nitrogen interaction is significant; the addition of phosphorus raise the soil microorganisms＇ activity when the carbon and nitrogen are both plentiful. In addition, under different nutrient status, the soil respiration rate reached the highest value at different time; the CNP （C ＋ N ＋ P） treatment at 3 d, and then the CN （C＋N） treatment at 5 d; the C and CP （C＋P） treatments reached the peak value at about 15 d.