减水减肥处理对露天菜田土壤磷分布的影响

以黑龙江省拉林露天菜田黑土为对象,对比分析常规水肥(WF)、减肥处理(W80%F)、减水处理(80%WF)、减水减肥配施秸秆处理(80%W80%F+S)下的土壤磷转化的变化,以期探究减水减肥处理下露天菜田土壤磷转化特征。结果表明:所有处理土壤全磷、有效磷垂直变化特征明显,呈现随着土壤深度增加而减少的趋势,且0~20 cm土层中的全磷、有效磷含量均高于其它土层,减水减肥配施秸秆处理显著降低了深层土中的有效磷含量(P<0.05),降低幅度为57.0%,抑制了磷向深层土移动。随着白菜生育的延长,减肥、常规水肥处理的土壤有效磷含量不断升高;而减水、减水减肥配施秸秆处理的土壤有效磷含量不断下降;减水、减肥、常规水肥处理的土壤有效磷含量在白菜生长的中后期达到最高后又缓慢下降。认为减水减肥配秸秆处理可减少土壤磷素淋溶的风险,降低淋溶液中全磷的含量,是对环境影响风险最小的可行水肥方案。

Effects of Reducing Irrigation and Reducing Fertilization Treatments on Phosphorus Distribution in Black Soil of Open-air Vegetable Field

This study focused on black soil of Lalin open-air vegetable fields in Heilongjiang Province and analyzed the effect on soil phosphorus transformation under the following treatment,conventional irrigation and fertilization(WF),reducing fertilization treatment(W80%F),reducing irrigation treatment(80%WF),and reducing irrigation and fertilization combined with straw return treatment(80%W80%F+S).The results showed that the vertical variation characteristics of total phosphorus and available phosphorus in all treatments were obvious,which decreased with increasing soil depth,and the total phosphorus and available phosphorus content in 0-20 cm soil layer was higher than those in other soil layers,reducing irrigation and fertilization combined with straw return treatment significantly reduced the available phosphorus contents in deeper soil(P<0.05)by 57.0%,thus inhibiting phosphorus moving to deeper layers.With the extending of cabbage growth stages,the available phosphorus contents in soil of reducing fertilization and conventional water and fertilizer treatments increased continually;the available phosphorus content in soils of reducing irrigation,reducing irrigation and fertilization combined with straw return treatments continued decreased continually.Available phosphorus contents decreased slowly after reaching the highest level in the middle and late stages of cabbage growth.Reducing irrigation and fertilization combined with straw return treatment could reduce the risk of soil phosphorus leaching and reduce the total phosphorus content in the leaching solution,which was a feasible irrigation and fertilization scheme with the lowest risk to the environment.