磷石膏与石灰石粉配施对新垦红壤耕地的改良效果

Improvement Effect of Combined Application of Phosphogypsum and Limestone Powder on Newly Cultivated Red Soil

新垦红壤耕地兼具有强酸与养分贫瘠等多种缺陷,需要采取多种措施加以改良。为了解磷石膏与石灰石粉配施对新垦红壤耕地降酸与增加矿质养分的作用,以新垦黄筋泥为研究对象,设计磷石膏、石灰石粉不同用量及其组合的盆栽试验,研究不同改良剂处理对土壤酸度、有效养分及作物生长的影响。结果表明,磷石膏和石灰石粉对土壤具有明显的降酸与增加有效钙的作用,其效果随用量增加而增加;等质量施用条件下,单施石灰石粉、磷石膏与石灰石粉配施对土壤的降酸效果高于单施磷石膏。在改善土壤矿物养分、物理性状和蔬菜生长方面,磷石膏与石灰石粉配施和单施磷石膏的效果高于单施石灰石粉。在试验条件下,施用磷石膏没有明显增加土壤中重金属的积累,且因土壤pH的提高蔬菜中Cd、Cr、Pb含量有所下降,但As含量呈轻微增加,对蔬菜中其他重金属积累的影响不明显。研究认为,对于酸化明显和养分低下的新垦红壤可采用磷石膏与石灰石粉配施替代单独施用石灰石粉加以改良,但应适当控制磷石膏施用量。

Newly cultivated red soil has many defects,such as strong acid and poor nutrient content,and needs to be improved by many measures.To understand the effect of phosphogypsum and limestone powder on reducing acidity and increasing mineral nutrients in the newly cultivated red soil,a pot experiment was designed to study the effect of applying different amounts and combinations of phosphogypsum and limestone powder on soil acidity,available nutrients and crop growth.The results showed that both phosphogypsum and limestone powder could significantly reduce soil acidity and increase soil available calcium,and the effect increased with the increasing dosage of amendments.Under the condition of equal mass application of the amendments,the effect of the single application of limestone powder or the combined application of phosphogypsum and limestone powder on the reduction of soil acidity was higher than that of the single application of phosphogypsum.The effects of the combined application of phosphogypsum and limestone powder or single application of phosphogypsum on the improvement of soil mineral nutrients,physical properties and vegetable growth were higher than those of single application of limestone powder.Under the experimental condition,the application of phosphogypsum did not significantly increase the accumulation of heavy metals in the soil,and the content of Cd,Cr and Pb in vegetables decreased due to the increase of soil pH,but the content of As increased slightly,which had no obvious effect on the accumulation of other heavy metals in vegetables.The results showed that the newly cultivated red soil with obvious acidification and low nutrients could be improved by the combined application of phosphogypsum and limestone powder instead of limestone powder alone,but the application amount of phosphogypsum should be controlled properly.