黄泥土施用磷石膏的后效试验

After effect of Phospho gypsum in Acidulous Yellow Upland Soil

3年磷石膏后效观察试验结果表明 :磷石膏在黄泥土上增产作用有明显的后效 ,但土壤和施用量不同 ,持续时间不一样。酸性黄泥土以 10 0～ 150 kg/ 6 6 7m2 后效较明显 ,持续时间超过三季作物 ;微酸性黄泥土只有 150 kg/ 6 6 7m2 的后效明显 ,持续时间达到三季作物。磷石膏的改土作用也有后效 ,但与供试土壤 p H值有关。土壤 p H值低 ,磷石膏的后效明显 ,持续时间较长 (三季作物 ) ;土壤 p H值高 ,后效作用不很明显 ,持续时间较短。因此 ,磷石膏宜在 p H值低于 5.

The field experiment was executed to investigate after effect of phospho gypsum in acid yellow soil from 1998 to 2000. The results showed that after effect of phospho gypsum varied with soil pH and application amount of phospho gypsum. Within soil pH 4.0～6.5, after effect of phospho gypsum have a negative correlation with soil pH and have a positive correlation with application amount of phospho gypsum (750～2 250 kg/ha). Phospho gypsum is suitable for applying in acidic yellow soil (pH≤5.0) and its proper application amount is 2250 kg/ha.