施用不同磷肥对植烟土壤中磷的淋失和有效磷的影响

采用土柱淋溶模拟试验和室内培养试验,研究不同磷肥施入土壤后磷的淋失和有效磷的变化.结果表明,在施磷量为35 mg/kg条件下,整个淋洗期间,钙镁磷肥、磷酸二氢钙、磷酸一氧铵、磷酸二氢铵、磷酸二氢钾5种肥料磷的淋失率很低;各处理从上而下各层土壤的Olsen-P质量比略有增加.施磷量为60 mg/kg、110 mg/kg、170mg/kg、230 mg/kg时.潮砂田肥料磷的淋失率分别为0.26%、0.74%、2.12%和3.17%;灰泥田肥料磷的淋失率分别为0.79%、1.31%、1.60%和1.94%.钙镁磷肥施人各种土壤后,随着培养时间的延长,土壤有效磷质量比逐渐增加,80 d后达到峰值并趋于稳定;磷酸二氢钾、磷酸二氧铵、磷酸一氢铵和磷酸二氢钙施人上壤后,土壤有效磷质量比逐渐降低,至培育60 d后.变化趋于平缓.不同土壤类型对磷的吸附固定率从大到小为潮砂田、灰泥田.

Effects of applying different P fertilizers on the phosphorus leaching as well as on the tobacco-planting soil

This paper is entitled to study the effects of phosphorus leaching and available phosphorus in the moist sandy field or the lime marl field by means of repacked soil columns and soil-cultures. The results of our study show that, with the presence of an amount of 35 mg/kg P fertilizer, the leaching rate of phosphorus in the calcium magnesium phosphate, Ca(H_2PO_4)_2, (NH_4)_2HPO_4, NH_4H_2PO_4 and KH_2PO_4 in the moist sandy field can be reduced to a very low level whereas the Olsen-P in such treatments tends to increase slightly from the surface soil to the underground layer. In addition, the Olsen-P of different layers in various soils tend to show the following order: the lime marl field > the moist sandy field. Besides, different amounts of application also greatly affect the phosphorus leaching rates, which can be illustrated as follows: Apply phosphate fertilizer with 60 mg/kg, 110 mg/kg, 170 mg/kg, 230 mg/kg (P), and we can find that the phosphorus leaching rates in the moist sandy field and the lime marl field can be reduce to 0.26%, 0.74%, 2.12%, 3.17% and0.79%, 1.31%, 1.60%, 1.94%, respectively. The phosphorus leaching rates of the moist sandy field tend to be lower than that in the lime marl field when 0 mg/kg, 60 mg/kg, 110 mg/kg (P) applied. In case the calcium magnesium phosphate is applied to all the above soils, with the time extension, the content of soil's available phosphate would increase gradually whereas the soil tends to be stable in 80 days if it received the highest amount of available phosphate. The content of the soil's phosphate available would gradually decrease when Ca (H_2PO_4 )_2, ( NH_4 )_2HPO_4, NH_4H_2PO_4 and KH_2PO_4 were applied to the above soils. Thus, it can be seen that the change of the P content proves to be minor and therefore tended to be stabilized. The P fixation ratios of different phosphorus fertilizers in various soils were found to obey the following order: the moist sandy field > the lime marl field.