[目的]有机肥减磷对于调控菜地土壤磷素的淋溶风险具有重要意义，然而其阻控磷淋失和稳定蔬菜产量的潜力还不清楚。[方法]以不施肥和菜地常用高磷含量有机肥(TP 2。03%，HP)为对照，设置总磷含量为1。75%(MHP)、1。32%(MP)和 1。06%(LP)3种低磷有机肥处理，进行空心菜设施栽培试验，考察不同处理对于土壤磷素淋溶、土壤磷含量及蔬菜产量的影响。[结果]空心菜生育前期(第一、二茬)是磷素淋失的关键时期，相比HP处理，低磷有机肥(MHP、MP、LP)处理土壤磷淋失强度第一茬分别降低 4%、21%和 31%(P＜0。05)，第二茬分别显著降低 24%、34%和 45%;土壤总磷含量第一茬分别下降 6。8%、21。2%和 19。2%(P＜0。05)，土壤有效磷含量分别下降 0%、21。6%和 20。0%(P＜0。05);空心菜产量不显著降低，第一茬MP和LP处理植株磷含量显著降低。表观分析表明，低磷有机肥处理显著降低了有机肥磷在土壤中的遗存。以土壤总磷和淋溶水总磷浓度进行分段回归分析显示，本实验背景土壤磷淋失阈值为土壤总磷 1。19 g kg-1。[结论]低磷有机肥可以有效降低土壤磷淋失强度，显著降低土壤磷遗存，不显著降低蔬菜产量。以实验区土壤为参照，建议在土壤磷高于 1。19 g kg-1 的土壤中使用磷含量小于1。75%的有机肥，在低于此值的土壤中使用磷含量大于等于1。75%的有机肥。
Effect of Phosphorus-Reducing Organic Fertilizer on Soil Phosphorus Leaching Loss and Water Spinach(Ipomoea aquatica Forsk)Yield
[Objective]Reducing phosphorus(P)content of organic fertilizer is of great significance to regulate the leaching risk of soil P in vegetable fields.But the potential of P-cutting of organic fertilizer is unclear to stabilize vegetable yield and decrease leaching loss.[Method]The field experiment was carried out,using high P organic fertilizer(HP,P 2.03%)as a contrast,high-middle P organic fertilizer(HMP,P 1.75%),middle P organic fertilizer(MP,P 1.32%),and low P organic fertilizer(LP,P 1.06%)were tested for the effect on soil P leaching loss,soil P content and vegetable yield.[Result]The early stage(the first and second crop)was the key period of P leaching loss.The leaching intensities of MHP,MP and LP reduced 4%,21%and 31%(P＜0.05)compared with HP in the first stage,and 24%,34%and 45%in the second stage,respectively.The soil total P content decreased 6.8%,21.2%and 19.2%(P＜0.05)in the first stage,respectively.The soil available P decreased 0%,21.6%and 20.0%(P＜0.05),respectively.The vegetable yield did not decrease significantly.The vegetable P contents of MP and LP treatments decreased significantly in the first stage.This study indicated soil total P was an alternately index to analyze the intensity of soil P leaching in in situ field.The leaching threshold was 1.19 g kg-1,MP and LP were the low leaching risk treatment,MHP and HP were high leaching risk treatment.[Conclusion]The P-reduction organic fertilizer may significantly lessened soil P leaching loss intensity,significantly decrease the legacy of P in soil and didn't decrease significantly vegetable yields.Using the soil P threshold value,the P reduction value and application patterns of organic fertilizer P content are recommended.Thus,it is recommended to use middle P organic fertilizer(P 1.32%)in soil with high P(Soil total P＞1.19 g kg-1),and high-middle P organic fertilizer(P 1.75%)in soil with low P(Soil total P＜1.19 g kg-1).
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