供磷型土壤调理剂在酸性土壤应用效果研究

我国南方酸性土壤常存在交换性铝含量极高和磷素供应不足的问题,如何有效改良南方酸化土壤,提高土壤活性磷含量是个重要的问题。本文以南方酸性红壤为供试土壤,通过土壤培养试验和玉米盆栽试验探究了基于磷尾矿、磷酸镁铵和石灰等为主要原料的供磷营养型土壤调理剂对酸性土壤的改良效果和对玉米磷素养分利用的影响。采用添加不同原料比例和数量的土壤调理剂进行土壤培养,结果表明施用量在4~8 g/kg时,可使土壤pH升高1.1~1.6个单位,显著降低土壤交换性铝和有效铁含量,增加土壤交换性钙、镁和有效磷含量;盆栽玉米试验结果表明,与空白对照相比,施用C3配方土壤调理剂明显改善玉米苗期生长和植株磷素营养,但是土壤调理剂中辅料(白云石/石灰+膨润土)对促进磷酸二铵的肥效要明显优于土壤调理剂的供磷主料(磷酸铵镁+磷尾矿),说明在供磷方面主料的作用效果优于与辅料相混,辅料在增加土壤酸性改良效果的同时也钝化了主料中的磷素,该调理剂的配方需要进一步调整。 

Application of Soil Nutrition Conditioners for Phosphorus Supply on Acidic Soil Improvement

Excessive soil exchangeable aluminum and phosphorus (P) deficiency are the common problems in acidic soils in Southern China. How to improve the soil quality and increase the soil available P in acidic soils are quite important and need to be studied. In this study, soil incubation experiments and pot experiments were conducted to investigate the improvement effects and nutrient supply of the nutritional soil conditioners in acidic red soil from Southern China. The soil conditioners were based on phosphorus tailings, ammonium magnesium phosphate and lime. Different components ratio and dosage of soil conditioners were incubated with acidic soil in the laboratory. The results showed that the soil pH raised by 1.1 to 1.6 with 4-8 g/kg soil conditioners added. Besides, soil exchangeable aluminum and efficient iron reduced significantly. And the exchangeable calcium，magnesium and effective P increased substantially. The results of the maize pot experiment showed that soil conditioners could significantly improve the growth of maize seedling stage and P absorption when compared with the control . But the supplementary components in the soil conditioners (dolomite or lime + bentonite) (S) could better improve the nutrient utilization of diammonium phosphate (DAP), compared with the nutrient utilization of the main components (phosphorus tailings + ammonium magnesium phosphate) (M). This indicated that the effect of M in P utilization was better than that of M and S together. S improved the quality of acid soil while stabilizing P in M. And the formula of soil conditioners in this experiments needs to be further adjusted.