有机肥与磷肥配施对滨海盐渍化土壤磷素淋洗风险的影响

摘要

针对滨海盐渍化土壤水稻种植过程中出现的磷素淋洗风险，采用田间微区试验，研究了不同用量有机肥和磷肥对滨海盐渍化土壤有效磷含量及磷素淋洗风险的影响。试验设磷肥与有机肥两个因素，3个磷（P2O5）水平，分别为P0：无磷，0 kg·hm-2；P1：低磷，64 kg·hm-2；P2：高磷，128 kg·hm-2。3个有机肥（碳）水平，分别为C0：无碳（有机肥0 kg·hm-2）；C1：低碳，450 kg·hm-2（有机肥1000 kg·hm-2）；C2：高碳，900 k·hm-2（有机肥2000 kg·hm-2）。共设7个处理：T1：无磷施用；T2：低磷；T3：高磷；T4：低碳低磷；T5：低碳高磷；T6：高碳低磷；T7：高碳高磷。结果表明，磷肥施用显著提高了土壤剖面中H2O-P、NaHCO3-P含量；低磷低碳处理下0~20 cm土层土壤中磷饱和度（DPS）较低磷处理低，其他土层土壤中磷饱和度无显著变化；而低磷高碳处理可显著提高40~60 cm土层土壤中磷饱和度，高于28.1%的临界饱和度；高磷低碳处理表层土壤有效磷含量为31.8 mg·kg -1，对整个剖面土壤中磷饱和度影响不大，磷素淋洗风险较小；而高磷高碳处理在提高表层土壤有效磷含量的同时，显著提高了20~40、40~60 cm土层土壤中磷饱和度，且均高于临界饱和度，导致整个土壤剖面具有很高的磷素淋失风险。在滨海盐渍化土壤水稻种植中，配施450 kg·hm-2C和64 kg·hm-2P2O5（碳磷比为15.1）时，磷素淋洗风险较低，而过量施用磷肥和有机肥将导致土壤磷素淋洗，利用效率降低。%The study was mainly concentrated on the effect of organic manure and phosphorus fertilizer on the phosphorus leaching risk in coastal saline soil, which was to choose the best formula of the organic manure and phosphorus supply in the coastal saline soil for rice. The micro zone test was adopted with two factors: phosphate fertilizer, 3 P (P2O5) levels: no P, 0 kg·hm-2, low P, 64 kg·hm-2 and high P, 128 kg·hm-2; organic fertilizer, 3 C levels: no C, no organic fertilizer, low C, 450 kg·hm-2 C (organic fertilizer 1000 kg·hm-2) and high C, 900 kg·hm-2 C (organic fertilizer 2000 kg·hm-2). And 7 treatments were designed: T1: no P; T2: low P; T3: high P; T4: low C and low P; T5: low C and high P; T6: high C and low P; T7: high C and high P.The results showed that H2O-P, NaHCO3-P in coastal saline soil significantly were increased with P fertilizer. In low phosphorus application, low carbon application decreased the degree of phosphorus saturation (DPS) in 0~20 cm soil, which had no effect on the soil DPS with other soils; and the high amount of carbon significantly increased the DPS in 40~60 cm soils, which was higher than the critical value 28.1%. In the high phosphorus application with low carbon addition treatment, could maintain the available phosphorus content (31.8 mg·kg-1) in surface soil, which led the phosphorus leaching risk was less. However, with high carbon added treatment, the soil available phosphorus was improved, meanwhile, the DPS in 20~40 and 40~60 cm soil was also significantly increased, which was more than the critical value 28.1% in the whole soil profile with high phosphorus leaching risk. In the coastal saline soil, the optimal application of the organic fertilizer and phosphate was 450 kg·hm-2 C and 64 kg·hm-2 P2O5 (ratio of C and P was15.1), respectively, so that the phosphorus leaching risk was low, while the excessive application of phosphate fertilizer and organic fertilizer would lead to the soil phosphorus leaching and low utilization efficiency.