生物炭与螯合剂配施条件下土壤无机磷的动态变化

Effects of biochar and chelating agent on dynamic change of inorganic phosphorus in soil

为了提高土壤磷素使用的有效性,以辽宁碱性土壤为研究对象进行试验研究。采用室内培养,测定了在不同地力下,生物炭与3种螯合剂(草酸、柠檬酸、EDTA)在低中高三种浓度下对土壤磷素的活化规律。从各形态无机磷自身活化情况来看,土壤中Ca2-P、Ca8-P的含量有所提高。其中Al-P的活化率最高,低中高地力在3种浓度下的平均活化率为34.5%,35.1%和35.3%,Ca-P的活化率最低,但是其贡献率最高,含量占到土壤总无机磷含量的74.4%、73.5%和72.9%。土壤无机磷总活化量以及各形态无机磷组分含量随着螯合剂浓度的升高而增多。相同浓度下,草酸的活化能力最强,其次为EDTA。低浓度时,柠檬酸对Fe-P的活化能力最强,草酸对Al-P的活化能力最强。在中、高浓度时,草酸对各形态无机磷的活化能力都最强。试验证明生物炭与螯合剂配施,可以有效增加土壤磷素无效态向有效态的转化。

In order to improve the availability of soil phosphorus,alkaline soil in Liaoning province was studied.In this study,indoor culture was used to determine the activation rules of soil phosphorus by biochar and three chelating agents(oxalic acid,citric acid and EDTA)at low,medium and high concentrations under different soil forces.From Self-activation of inorganic phosphorus in various forms of view,the contents of Ca2-P and Ca8-P in soil were increased.Among them,the activation rate of Al-P was the highest,the average activation rate was 34.5%,35.1%and 35.3%at three concentrations of low,medium and high soil fertility,and the activation rate of Ca-P was the lowest,but its contribution rate was the highest,accounting for 74.4%,73.5%and 72.9%of the total inorganic phosphorus content in the soil.The total activation amount of soil inorganic phosphorus and the content of inorganic phosphorus in various forms increased with the increase of chelating agent concentration.At the same concentration,oxalic acid had the strongest activation ability,followed by EDTA.At low concentration,citric acid had the strongest activation ability to Fe-P and oxalic acid had the strongest activation ability to Al-P.At medium and high concentration,oxalic acid has the strongest activation ability to all forms of inorganic phosphorus.It was proved that the combination of biochar and chelating agent could effectively increase the conversion of soil phosphorus from invalid state to effective state.