果园绿肥对土壤磷组分及磷素有效性的影响

Effects of Green Manure on Soil Phosphorus Fractions and Availability in Orchard

以天津市桃园土壤为研究对象,采用Tiessen磷分级方法研究绿肥栽培并利用条件下土壤磷组分含量变化和磷素活化周转特征。试验共设3个处理:绿肥覆盖(SC)、翻压(BU)和清耕对照(CT)处理。分别于绿肥处理1,4,7年后采集0—20,20—40 cm的土壤样品,测定全磷、活性磷库(Resin—P_(i)和NaHCO3—P)、中稳性磷库(NaOH—P)和稳定态磷库(Dil.HCl—P_(i)、Conc.HCl—P和Residual—P)含量。结果表明,与CT处理相比,SC和BU处理在各采样年份均提高了土壤全磷、Resin—P_(i)、NaHCO3—P、NaOH—P和Residual—P含量,降低Dil.HCl—P_(i)和Conc.HCl—P含量,处理间差异性随绿肥利用年限的增加而增加;其中,各指标BU处理均优于SC处理,且0—20 cm土层变化最为明显。绿肥利用7年后,BU处理0—20 cm土壤Resin—P_(i)、NaHCO3—P、NaOH—P和Residual—P含量较CT处理分别显著增加48.82%~128.41%,145.93%~231.16%,206.26%~590.06%和34.67%~37.66%,Dil.HCl—P_(i)和Conc.HCl—P含量分别显著降低12.37%~15.79%和43.72%~91.39%。综上,相对于清耕对照处理,果园绿肥栽培并利用可显著增加土壤活性磷库和中稳性磷库的比例,并显著降低稳定态磷库的比例;同时,随着绿肥利用年限的增加,土壤活性磷库和中稳性磷库的比例随之增加,稳定态磷库的比例随之降低。研究结果表明,果园绿肥栽培并利用可以有效促进土壤难溶性磷的活化周转,提高土壤磷素生物有效性。

Taking peach orchard as the research object,the effect of green manure on soil phosphorus fractions and phosphorus turnover characteristics were investigated by Tiessen’s phosphorus fractionation method.There were three treatments,including green manure utilization as surface cover(SC),buried underground(BU)and clean tillage control(CT).Soil samples from 0—20 and 20—40 cm were collected after green manure utilization for 1,4,and 7 years,to measure the content of total phosphorus,labile phosphorus pool(Resin-P_(i)and NaHCO3—P),moderately stable phosphorus pool(NaOH—P)and stable phosphorus pool(Dil.HCl—P_(i),Conc.HCl—P and Residual—P).The results showed that,compared with CT,SC and BU increased soil total phosphorus,Resin-P_(i),NaHCO3—P,NaOH—P and Residual—P contents,and decreased Dil.HCl—P_(i)and Conc.HCl—P contents in each sampling year.These differences were more pronounced with the increase of green manure utilization time.And,the BU showed the higher phosphorus availability than SC and the green manure mainly affected 0—20 cm soil layer.After seven years of cultivation and utilization of green manure,compared with CT,the contents of Resin—P_(i),NaHCO3—P,NaOH—P and Residual—P of BU were significantly increased by 48.82%~128.41%,145.93%~231.16%,206.26%~590.06%and 34.67%~37.66%,respectively,and the contents of Dil.HCl—P_(i)and Conc.HCl—P were significantly reduced by 12.37%~15.79%and 43.72%~91.39%,respectively.In summary,compared with CT,green manure utilization could significantly increase the proportion of soil labile and moderately stable phosphorus pool,and significantly decrease the proportion of stable phosphorus pool.Moreover,with the increasing green manure utilization years,the proportion of soil labile and moderately stable phosphorus pool also increased,while the proportion of stable phosphorus pool decreased.This study shows that the cultivation and utilization of green manure in orchards could effectively promote the mobilization and turnover of insoluble phosphorus and improve the bioavailability of soil phosphorus.