蚯蚓粪肥对水稻土磷形态及微生物活性的影响

Impacts of vermicompost application on phosphorus species and microbial activity in paddy soils

采用盆栽试验方法,以小白菜为试验作物,研究蚯蚓粪肥对水稻土磷形态以及微生物活性的影响。结果表明:蚯蚓粪肥对土壤pH、Eh、水溶态Fe(Ⅱ)、盐酸提取态Fe(Ⅱ)、微生物生物量碳、微生物生物量磷、微生物生物量碳磷比以及酸性磷酸酶活性均有显著影响(P<0.05);蚯蚓粪肥对于除稳定性磷C.HCl-Pi外的土壤各形态磷含量均有明显提高,其中对活性磷(Resin-P、NaHCO_3-Pi和NaHCO_3-Po)和中稳定性磷(NaOH-Pi和NaOH-Po)具有极显著性影响(P<0.01)。相关性分析结果表明:在蚯蚓粪肥添加的土壤中,酸性磷酸酶活性与微生物生物量碳之间存在极显著正相关关系,与NaHCO3-Po存在显著负相关关系,与Resin-P、NaOH-Po均达到极显著负相关水平;微生物生物量碳与Resin-P、NaHCO_3-Po之间均存在极显著负相关关系,与盐酸提取态Fe(Ⅱ)之间存在极显著正相关关系;盐酸提取态Fe(Ⅱ)与NaHCO_3-Po、NaOH-Pi之间均为显著负相关;NaHCO_3-Pi与NaOH-Pi之间存在极显著正相关关系,Resin-P与NaHCO_3-Po、NaOH-Po均存在极显著正相关关系。研究表明:蚯蚓粪肥能够有效促进土壤铁溶解和还原,进而促进NaOH-Pi释放;蚯蚓粪肥添加有效改善土壤微生物环境,促进微生物对磷的活化和固持,同时增强了土壤酸性磷酸酶活性,其对NaOH-Po活化具有显著影响;蚯蚓粪肥添加的土壤中Resin-P主要来自NaHCO_3-Po、NaOH-Po的分解,而NaOH-Pi是NaHCO_3-Pi的主要来源。

In this study,a pot experiment was conducted to investigate the effects of vermicompost application on phosphorus(P)transformation and microbial activity in a paddy soil cropped with pakchoi.The results showed that:(1)vermicompost application significantly affected the pH,Eh,water soluble Fe(Ⅱ),hydrochloric acid extractable Fe(Ⅱ),microbial biomass carbon(C),microbial biomass P,microbial biomass C/P ratio,and acid phosphatase activity of paddy soils(P<0.05)and(2)with the exception of C.HCl-Pi,vermicompost application greatly increased the contents of various P species in soil;specifically,labile P(including Resin-P,NaHCO3-Pi and NaHCO3-Po)and moderately stable P(including NaOH-Pi and NaOH-Po)were significantly increased(P<0.01).Correlation analyses indicated the following:acid phosphatase activity had a significant positive correlation with microbial biomass C,but a significant negative correlation with NaHCO3-Po(P<0.05),Resin-P(P<0.01),and NaOH-Po(P<0.01);microbial biomass C had a significant negative correlation with both Resin-P and NaHCO3-Po(P<0.01),but a significant positive correlation with hydrochloric acid extractable Fe(Ⅱ)(P<0.01);hydrochloric acid extractable Fe(Ⅱ)had a significant negative correlation with both NaHCO3-Po and NaOH-Pi(P<0.05);NaHCO3-Pi had a significant positive correlation with NaOH-Pi(P<0.01);and Resin-P had a significant positive correlation with both NaHCO3-Po and NaOH-Po(P<0.01).These results indicated that earthworm cast application could effectively promote the dissolution and reduction of Fe(Ⅲ)and the consequent release of NaOH-Pi.In addition,earthworm cast application could effectively improve soil quality,promote P activation and fixation by soil microorganisms,and enhance acid phosphatase activity,which has a significant impact on NaOH-Po.The Resin-P increase was mainly due to the decomposition of NaHCO3-Po and NaOH-Po,and NaOH-Pi was the main source of NaHCO3-Pi.These results are expected to provide a scientific basis for improving the utilization rate of P fertilizers and promote the better use of vermicompost.