连续淋洗对山东省主要土壤磷素有效性及磷库的影响

Effect of Continuous Leaching on Phosphorus Availability and Phosphorus Pool of Main Soils in Shandong Province

研究采取室内模拟降雨淋洗的方法,研究了连续淋洗对山东省3大土类磷素有效性和磷库的影响。结果表明,3种土壤的磷淋失量均随着供磷水平的提高而升高。3种土壤出现磷淋失量峰值的时间有着明显差异,褐土施磷处理的磷淋量峰值分别出现在第3 d,4 d和5 d;而潮土高磷和低磷处理的磷淋洗最高值分别出现在第2 d和3 d;而棕壤不同施磷处理的磷淋洗高峰值均出现在第2 d。在相对较低的施磷水平下(P3以下),3大土类的速效磷含量基本均保持在20μg/g左右,再提高供磷水平,褐土和棕壤的土壤速效磷含量随施磷量的增加显著升高,而潮土的速效磷含量则随着施磷量的增加先升高后降低。在3大土类中,全磷含量最高的是褐土,其次是潮土,再次是棕壤。在淋洗条件下,褐土的土壤磷库相对变化不大,而潮土和棕壤的磷库则随施磷量的变化有着较大的起伏。因此,施磷水平控制在P3水平(180 kg P/hm2),3大土壤的磷淋失量较低,土壤速效磷变化不大,有利于减少土壤磷素淋失到水体的风险,也保证了土壤磷的供应能力。

Simulated continuously rainfall leaching was used to study the effect of continuous water leaching on phosphorus availability and phosphorous poor of three main soil types in Shandong province.Results showed that P leaching amounts of three soils increased when the P levels were increased.Times of peak value of P amount of leaching were different among three soils,the peaks values of P amount of leaching appeared respectively at 3d,4d and 5d in cinnamon soil;while the peak values of high P and low P treatments of fluvo-aquic soil appeared at 2 d or 3 d,and the peaks of P leaching amounts of brown soil appeared at 2 d.With the lower P application（≤P3）,the Olsen P contents of three soils were almost kept at 20 μg/g.When P supply was increased,the Olsen P contents of cinnamon soil and brown soil increased markedly while that of fluvo-aquic soil was increased firstly then decreased.Among the three soils,cinnamon soil had the highest content of P,then the fluvo-aquic soil,and the last brown soil among three soils.Under the leaching condition,soil phosphorous pool of cinnamon soil varied hardly,while those of fluvo-aquic soil and brown soil varied markedly.Thus,if P application was controlled no more than P3（180 kg P/hm^2）,phosphorous amounts of leaching wouldn＇t varied markedly,so this could help to reduce the risk of leaching P getting into water and keep the supply ability of soil phosphorous.