150kg/mu of slag powder of yellow phosphorus or 100kg/mu of lime could be used as the lower limit for controlling pH drop of acid paddy bellow pH4,and 300kg/mu of lime as the upper limit for improving the acid paddy.

• 亩用黄磷炉渣粉150kg或亩用石灰100kg可作为控制“灌溉水及盐浸耕层土壤pH均为4.；0的煤锈水田土壤”pH继续下降的下级指标，亩用石灰300kg可作为这类土壤改良用量的上限指标；