柠檬酸对土壤养分的活化及对作物吸收Fe、P的影响

Effect of citrate on nutrient activation in calcareous soil and on P and Fe uptake by crops

土壤pH值是影响石灰性土壤Fe、Zn、Mn等微量元素有效性的重要因素,利用土壤培养法,研究了不同浓度柠檬酸溶液对石灰性土壤的pH值以及对P、Fe、Mn、Zn等元素的活化效应。结果表明,浓度高于0.001mol/L的柠檬酸溶液培养土壤,可降低土壤pH值,增加土壤有效P、Fe、Mn、Zn等元素的质量分数。培养24h后,P、Fe、Mn、Zn等有效养分质量分数最高,随着培养时间的延长,有效养分的质量分数下降,活化效果减弱,土壤表现出一定的钝化效应。利用盆栽模拟滴灌施肥条件,柠檬酸溶液处理可显著促进花生、菜豆植株的生长,叶片SPAD读数增加,并提高植株对P、Fe元素的吸收量,因此滴灌施肥条件下,可考虑使用柠檬酸增加石灰性土壤根区微量元素的有效性。

Soil pH could affect micronutrients availability in calcareous soil. High pH value is a disadvantage for increasing avail- ability of the microelement. Effect of citrate solution on pH and the activation of P, Fe, Mn and Zn in calcareous soil was studied through soil cultivating experiment. The research indicated that citrate solution with the concentration 0.001 mol/L decreased soil pH and increased the availability of P, Fe, Mn and Zn in calcareous soil. Calcareous soil showed buffer effect significantly with soil available nutrient content. The contents were the highest in 24 h, and decreased in 48 h and 72 h. Pot experiments with the drip irri- gation of citrate solution showed the increase uptake of P and Fe by bean and peanut and improved plant weights. It is concluded that citrate solution can be used in drip irrigation to improve availability of the microelements.