[目的]研究不同桉树枝条废弃物生物炭施用量对桉树人工林土壤磷形态转化及磷素有效性的影响,评估生物炭对土壤磷素的活化潜力,为生物炭在农林业土壤改良中的应用提供参考依据.[方法]依托2017年开展的桉树人工林生物炭长期定位试验,按生物炭与土壤的质量百分比,设置0(CK)、0.5％(T1)、1.0％(T2)、2％(T3)、4％(T4)和6％(T5)共6个处理,一次性施用生物炭5年后测定不同处理下0～10、10～20和20～30 cm 土层中土壤全磷、有效磷、无机磷和有机磷形态的含量.[结果]与CK相比,在0～30 cm 土层中,施用生物炭能显著增加土壤全磷、有效磷、二钙磷、铝磷、铁磷、八钙磷、活性有机磷和中等活性有机磷含量并提高磷素活化系数(P＜0.05),降低十钙磷、闭蓄态磷、中稳定性有机磷和高稳定性有机磷含量.在0～30 cm 土层中,不同生物炭处理下土壤无机磷和有机磷组分含量平均值的大小分别为铁磷＞铝磷＞闭蓄态磷＞八钙磷＞二钙磷＞十钙磷,中等活性有机磷＞活性有机磷＞中稳定性有机磷＞高稳定性有机磷.随着土层深度的增加,在同一生物炭处理中,土壤全磷、有效磷、无机磷和有机磷组分含量均趋于减少.土壤有效磷分别与pH、有机质、全磷、二钙磷、八钙磷、铝磷、铁磷、活性有机磷和中等活性有机磷之间呈极显著正相关(P＜0.01).主成分分析表明,施用生物炭对土壤无机磷组分、有机磷组分和有效磷具有正向作用;与有机磷组分相比,施用生物炭对土壤无机磷组分的影响更大.[结论]桉树枝条废弃物生物炭通过自身中磷素的释放和对土壤理化性质的积极作用,显著增加土壤有效磷和磷组分含量,促进土壤中难溶态磷向有效态磷的转化和有机磷向无机磷的转化,提高桉树林土壤磷素有效性和土壤供磷能力.
Effects of biochar application for five years on soil phosphorus in Eucalyptus plantations in northern Guangxi
[Objective]The present paper aimed to study the effects of application amounts of biochar from different Eucalyptus branches on soil phosphorus transformation and availability,to evaluate the potential of soil phosphorus activation,and to provide a basis for the practical application of biochar in agricultural and forestry soil improvement.[Method]In a long-term positioning test of biochar application from 2017,six different treatments were selected:0(CK),0.5％(T1),1.0％(T2),2.0％(T3),4.0％(T4),and 6.0％(T5)in terms of mass percentage of biochar to soil.The contents of soil total phosphorus(TP),available phosphorus(AP),inorganic phosphorus(IP)and organic phosphorus(OP)components in different soil layers of 0-10,10-20 and 20-30 cm following the different treatments were meas-ured after five years of biochar application.[Result]Compared with the CK,soil TP,AP,dicalcium phosphorus(Ca2-P),aluminium phos-phate(Al-P),ferric phosphate(Fe-P),ocalcium phosphorus(Ca8-P),labile organic phosphorus(LOP),moderately labile organic phos-phorus(MLOP)and phosphorus activation coefficient(PAC)in 0-30 cm soil layers all significantly increased with the application of bio-char(P＜0.05),and soil decalcium phosphorus(Ca10-P),occluded phosphorus(O-P),moderately resistant organic phosphorus(MROP)and highly resistant organic phosphorus(HROP)all decreased,respectively.In 0-30 cm,the trend of the average value of IP and OP components under different biochar treatments followed the increasing order of Fe-P＞Al-P＞O-P＞Ca8-P＞Ca2-P＞Ca10-P,moderately la-bile organic phosphorus(MLOP)＞labile organic phosphorus(LOP)＞MROP＞HROP.The contents of TP,AP,IP and OP in soil all de-creased with the deepening of the soil layer.AP was extremely significantly positive correlated with pH,soil organic matter(SOM),TP,Ca2-P,Ca8-P,Al-P,Fe-P,LOP and MLOP respectively(P＜0.01).The principal component analysis revealed that biochar had a positive effect on soil IPcomponents,OP components and AP.Compared to OP components,biochar had a greater impact on soil IP components.[Conclusion]The Eucalyptus branch waste biochar significantly increases the content of soil AP and phosphorus forms after five years of ap-plication by releasing of phosphorus content from biochar itself and its positive impact on soil physico-chemical properties,and it promots the conversion of insoluble phosphorus to effective phosphorus and organic phosphorus to inorganic phosphorus in the soil,which is conducive to improving the availability and supply capacity of soil phosphorus.
万方数据
维普
