施肥对川中丘陵杨树人工林土壤生物活性的影响

Effect of Fertilization on Soil Biological Activity for Poplar Plantation in Sichuan Hilly Basin

以川中丘陵区3年生I-107杨树(Populus×euramericana cv.‘74/76’)人工林为研究对象,通过对丘间平地和丘上坡地两种立地条件样地进行施肥(氮肥+磷肥+农家肥)处理,研究丘间平地和丘上坡地土壤微生物数量、土壤酶活性和土壤养分含量对施肥的响应。结果表明:丘间平地的土壤微生物数量、酶活性、土壤养分含量都高于丘上坡地,除酶活性外其他指标差异均达到显著水平(P<0.05);土壤微生物数量、土壤酶活性和有效养分含量随着土层加深逐渐降低,且不同土层之间差异显著(P<0.05);施肥可显著提高土壤微生物数量、酶活性和养分的含量(P<0.05);施肥与立地条件两者交互作用显著(P<0.05)。从土壤养分供给角度看,在川中丘陵区,平地土壤较坡地更适合种植杨树,在两种立地上施肥均可提高土壤肥力,且在平地更为显著。坡地施肥土壤微生物数量、酶活性、养分含量均高于平地对照,施肥可以在一定程度上弥补地位质量引起的土壤肥力的不足。

This study selected 3-year I-107 poplar(Populus×euramericana cv.'74/76') plantation in Sichuan hilly basin as the research object, was to investigate the responses of soil microorganism quantity, soil enzyme activity and soil nutrient to fertilizer application(nitrogen fertilizer + phosphate fertilizer + farmyard manure) in flat and slope land respectively. The results indicated that soil microbial quantity, soil enzyme activity and soil nutrient content in flat were higher than them in slope-land respectively. Except the enzyme activities, the variance analysis had a significant difference between two site conditions(P<0.05). In addition, these indices reduced gradually with the soil depth increase and the significant difference occurred between different depths(P<0.05). Fertilization obviously improved soil biological activity(P<0.05). The interaction between fertilization and site conditions was significant(P<0.05). From the angle of soil nutrient supplement, we concluded that the flat-land was more suitable for poplar plantation than slope-land in Sichuan hilly basin. Soil fertility in two sites were all increased by fertilization, meanwhile the flat-land was more obvious. Soil microbial quantity, soil enzyme activity and soil nutrient content in slope-land were higher than in flat-land due to fertilitzation. Therefore, fertilization could offset soil fertility shortage which was caused by location in a certain degree.