辽宁省不同土地利用对土壤微生物量碳氮的影响

Effects of Different Land Use Patterns on Soil Microbial Biomass Carbon and Nitrogen in Liaoning Province,China

通过野外调查采样和室内氯仿熏蒸提取法分析,研究了辽宁省旱地、稻田、湿地、草地、森林、果园6种不同土地利用方式共计35个样地表层土壤(0～10 cm、10～20 cm、20～30 cm)对土壤微生物量碳(SMBC)和土壤微生物量氮(SMBN)的影响。结果表明,土地利用方式对土壤微生物量有显著影响,其中土壤微生物量碳依次为森林>湿地>稻田>旱地>果园>草地;土壤微生物量氮则为森林>旱地>稻田>果园>湿地>草地。土壤微生物量碳氮均表现为森林显著高于其他土地利用方式,湿地、稻田、旱地、果园高于草地。除旱地和稻田,土壤微生物量碳随土层加深含量递减;而土壤微生物量氮在6种土地利用类型中,均表现为随土层加深含量递减。相关分析表明,土壤微生物量碳、氮之间显著相关,土壤微生物量碳、氮是可以表征土壤肥力的敏感因子。

Soil microbial biomass carbon（SMBC）and soil microbial biomass nitrogen（SMBN）are the important factors to evaluate soil quality and fertility.The objective of this study is to discuss the effect of different land use patterns on contents of SMBC and SMBN.Based on the field investigation,six land use patterns with 35 sampling sites were selected in Liaoning Province,including dry land,paddy field,wetland,grass-land,woodland and orchard.Soil samples of three soil layers,i.e.0～10 cm,10～20 cm and 20～30 cm,were collected from September 19 to 28,2007 by soil profile method.SMBC and SMBN contents were measured by chloroform fumigation extraction method.Results showed that the effects of land use patterns on soil microbial biomass were significant.The contents of SMBC and SMBN were obviously different in different land use patterns of Liaoning Province.The order of SMBC contents in 0~30 cm deep soil layer was：woodlandwetlandpaddy fielddry land orchardgrassland,while that of SMBN contents was：woodlanddry landpaddy fieldorchardwetlandgrassland.SMBC and SMBN contents were all higher in woodland than in other five land use patterns,while those were all lower in grassland.The deeper soil layers were,the less SMBC contents were in woodland,wetland,grassland and orchard.There was not an obvious rule for SMBC contents in dry land and paddy field.The deeper soil layers were,the less SMBN contents were in six land use patterns.There was a significant positive correlation between SMBC and SMBN.Their correlation coefficien（tR）reached 0.894 6.It suggested that the contents of SMBC and SMBN were the sensitive indi-cators for soil fertility.The results could provide references for agricultural structure regulation and management in Liaoning Province.