长期施用有机肥对设施番茄土壤有效磷含量及磷素淋失风险的影响

Effects of long-term application of organic fertilizer on soil available phosphorus content and leaching risk in greenhouse tomato cultivation

  • 摘要: 探讨设施蔬菜长期施用有机肥的土壤有效磷含量及磷素淋失风险, 可为设施蔬菜栽培合理施肥提供重要参考。以连续8 a设施番茄栽培田间定位施肥试验为依托, 选择不施肥(CK)、单施化肥(NPK)及与低、中、高量有机肥配施(M1NPK、M2NPK、M3NPK) 5个处理, 研究各施肥处理土壤全磷(Total-P)、有效磷(Olsen-P)和可溶性磷(CaCl2-P)含量及其剖面分布特征, 分析了土壤磷素环境阈值和农学阈值随剖面分布的变化以及设施番茄栽培适宜的磷素施用量。结果表明: 在0~50 cm土层, 各处理土壤Total-P、Olsen-P和CaCl2-P含量均随土层深度的增加呈逐渐下降趋势, 其含量均表现为0~10 cm土层显著高于30~50 cm土层(P<0.05); 与CK相比, 各施肥处理土壤Total-P、Olsen-P和CaCl2-P含量均有所增加, 且随有机肥施用量的增加而增加, 且施用中量(M2)和高量(M3)有机肥对0~20 cm土层土壤Total-P、Olsen-P和CaCl2-P含量的影响显著(P<0.05)。在0~10 cm、10~20 cm、20~30 cm、30~40 cm和40~50 cm土层, 土壤磷素环境阈值随土层深度的增加呈先上升后下降趋势, 其数值依次为139.6 mg·kg−1、152.4 mg·kg−1、133.5 mg·kg−1、86.1 mg·kg−1和42.3 mg·kg−1; 在0~10 cm、10~20 cm、20~30 cm和30~40 cm土层, 土壤磷素农学阈值随土层深度的增加而逐渐降低, 依次为185.1 mg·kg−1、120.5 mg·kg−1、92.8 mg·kg−1和56.0 mg·kg−1。以土壤磷素农学阈值所对应的土壤Olsen-P含量作为磷素淋失风险评价标准, 通过土壤Olsen-P含量与施磷量(P2O5)之间的相关关系, 求出设施番茄栽培适宜磷素(P2O5)用量为344.9~530.3 kg∙hm−2, 其中有机肥供应的磷素(P2O5)用量为119.9~305.3 kg·hm−2。综上, 连续8 a设施番茄栽培定位施肥条件下, 在施用化学氮磷钾肥(N 375 kg·hm−2、P2O5 225 kg·hm−2和K2O 450 kg·hm−2)的基础上配施低量有机肥(15 000 kg·hm−2), 不仅可以提高0~20 cm土壤有效磷含量, 使番茄产量显著增加, 而且可以有效控制土壤磷素淋失风险。

     

    Abstract: This study explored the soil available phosphorus content and leaching risk of long-term application of organic fertilizers under greenhouse tomato cultivation to provide an important reference for rational fertilization in greenhouse tomato cultivation. Based on a field experiment of located fertilization in greenhouse tomato cultivation over eight years, five treatments were selected: no fertilization (CK), application of chemical fertilizers (NPK), and combined application of low, medium, and high amounts of organic fertilizer and chemical fertilizers (M1NPK, M2NPK, M3NPK). The contents and profile distribution of soil total phosphorus (Total-P), available phosphorus (Olsen-P), and soluble phosphorus (CaCl2-P) in each fertilization treatment were studied. The changes in the soil phosphorus environmental and agricultural thresholds with profile distribution, and appropriate phosphorus application amount in greenhouse tomato cultivation were analyzed. The results showed that the contents of Total-P, Olsen-P, and CaCl2-P in all treatments decreased gradually with increasing soil depth in the 0–50 cm soil layer, and their contents in the 0–10 cm soil layer were significantly higher than those in the 30–50 cm soil layer (P<0.05). Total-P, Olsen-P, and CaCl2-P contents increased in all fertilizer treatments compared with CK, and they increased with the amount of organic fertilizer applied, and the effect of medium (M2) and high (M3) organic fertilizer application on Total-P, Olsen-P, and CaCl2-P contents in the 0–20 cm soil layer was significant (P<0.05). In the 0–10 cm, 10–20 cm, 20–30 cm, 30–40 cm, and 40–50 cm soil layers, the environmental thresholds of soil phosphorus increased first and then decreased with increasing soil depth, which were 139.6 mg·kg1, 152.4 mg·kg1, 133.5 mg·kg1, 86.1 mg·kg1 and 42.3 mg·kg1, respectively. In the 0–10 cm, 10–20 cm, 20–30 cm, and 30–40 cm soil layers, the agriculture thresholds of soil phosphorus decreased gradually with increasing soil depth, which were 185.1 mg·kg1, 120.5 mg·kg1, 92.8 mg·kg1, and 56.0 mg·kg1, respectively. Taking the soil Olsen-P content corresponding to the soil phosphorus agriculture threshold as the risk assessment criterion of phosphorus leaching, through the relationship between soil Olsen-P content and phosphorus application rate (P2O5), it was inferred that the suitable amount of phosphorus (P2O5) for greenhouse tomato cultivation was 344.9−530.3 kg·hm2, and the amount of P2O5 supplied by organic fertilizer was 119.9−305.3 kg·hm2. Under the condition of located fertilization in greenhouse tomato cultivation for 8 years, on the basis of chemical nitrogen, phosphorus, and potassium fertilizers (N 375 kg∙hm2, P2O5 225 kg∙hm2, and K2O 450 kg∙hm2), the application of a low amount of organic fertilizer (15 000 kg·hm2) could not only improve the available soil phosphorus content at 0–20 cm and significantly increase the tomato yield but also effectively control the risk of soil phosphorus leaching.

     

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