有机物料与锌肥配施对石灰性土壤锌有效性及形态转化的影响

Effects of combined addition of organic materials with zinc fertilizer on zinc availability and transformation in calcareous soil

采用尼龙网袋田间填埋培养法探究了外源施锌条件下石灰性土壤Zn有效性及形态转化对不同有机物料(作物秸秆、生物菌肥、黄腐酸和腐熟鸡粪)的响应.结果表明:与对照相比,Zn肥单施和与有机物料配施均显著提高了土壤全Zn含量(7.2%~13.8%)和DTPA-Zn含量(2.1~2.8倍).在施Zn条件下,有机物料对土壤全Zn和DTPA-Zn的贡献量表现为腐熟鸡粪>生物菌肥>玉米秸秆>黄腐酸,但外源锌的DTPA-Zn转化率以添加秸秆和生物菌肥处理最高.与单施Zn肥相比,有机物料与Zn配施处理显著提高了土壤有机质含量,促进了松结有机态Zn的形成,进而提高了土壤Zn转移因子,降低了Zn分配指数.不同物料与Zn肥配施土壤Zn有效性及形态转化之间存在差异,这可能与有机物料自身性质如腐熟度和含Zn量有关.尽管秸秆与Zn配施对DTPA-Zn含量的提升效果不及生物菌肥或腐熟鸡粪与Zn配施,但综合考虑环境和经济效益,其仍是改善缺锌石灰性土壤Zn有效性的最佳选择.

To investigate the changes of Zn availability and transformation in calcareous soil,orga-nic materials(maize straw,biofertilizer,fulvic acids,and chicken manure)were thoroughly mixed with the soils amended with Zn fertilizer in the nylon net bags and buried in a field.Results showed that compared with control(neither Zn nor organic materials),Zn fertilizer alone and combined addition with organic materials significantly increased soil total Zn concentration(7.2%-13.8%)and DTPA-Zn concentration(2.1-2.8 folds).For the Zn amended treatments,the contributions of organic amendments to soil total Zn and DTPA-Zn concentration decreased in the order of chicken manure>biofertilizer>maize straw>fulvic acids.The highest conversion rate of exogenous Zn into DTPA-Zn occurred in the treatments with straw and biofertilizer.In comparison with single Zn application,combination of Zn fertilizer with organic materials increased soil organic matter and stimulated more Zn weakly bound to organic matter,enhanced mobility factor and reduced distribution index of Zn in soil.The differences in soil Zn availability and transformation among the combinations of Zn fertilizer and organic materials were likely linked to the inherent properties of organic materials such as maturity degree and Zn content.Considering the environment safety and cost reduction,combining Zn fertilizer and straw return was the best practice to enhance Zn availability in the Zn-deficient calcareous soil,although its contribution to Zn availability was less than the combination of biofertilizer or chicken manure with Zn fertilizer.