外源磷添加对茶园土壤磷有效性和微生物量碳、氮、磷的影响

摘要

贵州茶园土壤普遍缺磷,土壤微生物可活化土壤难溶性磷提高植物磷素养分,对茶园土壤肥力和土壤养分的有效性具有重要的指示意义.研究了6种施磷处理(不施磷,施25mg/kg、50mg/kg、75mg/kg、100mg/kg、150mg/kg KH2PO4)对贵州湄潭县4个茶园表层土壤(0-20cm)土壤速效磷含量及微生物量碳、氮、磷的影响.结果表明,(1)研究区域土壤pH为4.60,较适宜茶树生长,有机碳、全氮含量分别在6.86-19.18mg/L、2.25-13.50mg/L之间,茶园土壤趋于有机碳积累;(2)土壤速效磷含量在0.37-27.44mg/L之间,施农家肥的MT3样点处于丰富、施有机肥的MT2样点处于较丰富、较少施肥的MT1和MT4样点处于很缺乏水平,外源磷添加使得处于磷较丰富、磷缺乏水平的样点土壤速效磷含量增加,处于磷丰富水平的样点土壤速效磷含量短期内先降后升;(3)施肥和管理模式较好的MT2、MT3样点微生物量碳、氮较高,且不同施磷处理均能增加研究区域土壤微生物量碳、氮含量;(4)研究中土壤微生物量磷出现负值,建议提取酸性土壤微生物量磷时延长浸提时间,使熏蒸释放的生物量磷完全水解.上述结果表明,研究区域土壤有机碳缺乏,外源磷的添加有利于缺磷土壤速效磷含量的增加,并可增加茶园土壤微生物生物量碳、氮含量.%The soil of tea plantation in Guizhou Province is phosphorus deficient in general.Soil microorganisms can activate insoluble soil phosphorus and increase plant phosphorus nutrient content, which is an important indicator for the soil fertility and the soil nutrient effectiveness.By using 6 phosphorus treatments (0 phosphorus, 25 mg/kg, 50 mg/kg, 75 mg/kg, 100 mg/kg, 150 mg/kg KH2PO4), the soil available phosphorus content and microbial biomass of carbon, nitrogen and phosphorus at top soil (0-20 cm) of 4 tea plantations in Meitan County, Guizhou Province were studied.The results showed that: (1) The soil pH in the study area was 4.60, which was suitable for tea growth.The contents of organic carbon and total nitrogen were 6.86-19.18 mg/L and 2.25-13.50 mg/L respectively, which indicated that the tea soil tends to accumulation of organic carbon; (2) Soil available P content, which ranged from 0.37 mg/L to 27.44 mg/L, was rich at MT3, slightly rich at MT2, and deficient at MT1 and MT4.The application of exogenous phosphorus increased the content of available phosphorus in soils with slightly rich and deficient phosphorus, while the available phosphorus content in soils with rich phosphorus decreased at the beginning and then increased; (3) Soil microbial biomass of carbon and nitrogen in MT2 and MT3 samples, which were well fertilization and management, were higher than other treatments.The soil microbial biomass of carbon and nitrogen increased with application of exogenous phosphorus; (4) There was a negative value of soil microbial biomass phosphorus content.We propose to extend the extraction time in the extraction of soil microbial biomass phosphorus in acid soil and to fully hydrolyze the biomass phosphorus released by fumigation.The above results show that soil organic carbon is deficient in the study area, and exogenous phosphorus can increase available phosphorus content in soils with phosphorus deficiency, and can increase the soil microbial biomass carbon and nitrogen content in tea plantation.