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对取自科尔沁沙地东南部3种典型植被(草地,樟子松人工林,杨树人工林)下的0–20cm土壤进行了室内冻融处理(于–12℃冻10天,然后于20℃培养10天)和常温培养(于20℃培养20天),测定了培养过程中土壤NO3–-N、NH4+-N、活性无机磷(LPi)和微生物磷含量。结果表明,冻融处理使土壤的净氮矿化速率和硝化速率降低了50%~85%,且冻融的影响在杨树人工林中最大。除LPi和NH4+-N含量在刚解冻时有所升高外,土壤NH4+-N、LPi和微生物磷含量受冻融处理的影响不显著。冻融对土壤氮转化的影响主要是由于冻融过程中土壤生物过程的变化引起的,而土壤有效磷几乎不受冻融影响可归因于研究区冬季土壤的干旱。图2表2参25。
Freezing and thawing treatments were conducted on 0-20 cm soil from three typical vegetations (grassland, Pinus sylvestris var. Mongolica and poplar plantation) from southeastern Horqin sandy land (frozen at -12 ° C for 10 days and then at 20 ℃ for 10 days) and at room temperature (20 ℃ for 20 days). The contents of NO3 - N, NH4 + -N, LPI and microbial phosphorus in the soil were measured. The results showed that the freeze-thaw treatment reduced the net nitrogen mineralization rate and the nitrification rate by 50% -85%, and the effect of freeze-thaw was the largest among poplar plantations. Except for LPi and NH4 + -N content increased at the time of fresh thawing, the content of soil NH4 + -N, LPi and microbial phosphorus was not significantly affected by freeze-thaw treatment. The effects of freeze-thaw on soil nitrogen transformation are mainly caused by the changes of soil biological processes in the process of freezing and thawing. However, the effect of freezing and thawing on soil available phosphorus almost can be attributed to the soil drought in winter in the study area. Figure 2 Table 2 Reference 25.