氮肥与有机肥配施协调土壤固定态铵与可溶性氮的研究

【目的】 土壤固定态铵是肥料氮的一个“临时贮藏库”，可逐渐释放以供作物利用，土壤可溶氮则是土壤固定态铵的重要来源，因此研究设施条件下氮肥与有机肥配施对土壤固定态铵和可溶性氮含量的动态变化以及相互关系的影响，对于设施生产中安全高效的施肥管理有着重要意义。 【方法】 以番茄为试材，温室内连续两年进行田间小区试验，设不施肥(CK)、施N量0、187.5、375. 562.5 kg/hm2 (N0、N1、N2、N3)、单施有机肥(M，75000 kg/hm2)以及有机肥与氮肥配施处理(MN0、MN1、MN2、MN3)。分析了土壤固定态铵和可溶性氮(土壤矿质氮和可溶性有机氮)含量动态变化。 【结果】 施肥显著提高了0-30 cm土层土壤固定态铵和可溶性氮的含量(P < 0.01)；各施肥处理均以第1穗果膨大期时含量最高。总体来看，不施有机肥条件下，土壤固定态铵和矿质氮、可溶性有机氮的含量均以施N 375.0 kg/hm2处理为最高，而在氮肥与有机肥配施条件下，以施N 375.0 kg/hm2与有机肥75000 kg/hm2配施处理和施N 562.5 kg/hm2与有机肥75000 kg/hm2配施处理的土壤固定态铵和矿质氮、可溶性有机氮含量为最高，但未发现氮肥施用量对土壤固定态铵含量产生显著影响；除收获期20-30 cm土层外，整个生长季内土壤固定态铵和矿质氮含量之间均有显著的正相关关系(P < 0.05)，部分土层土壤固定态铵与可溶性有机氮之间也有显著的正相关关系(P < 0.05)。 【结论】 设施番茄栽培条件下，土壤固定态铵和可溶性氮在土壤氮素的固持与释放方面极显著相关，施无机N 375.0 kg/hm2配合有机肥75000 kg/hm2，可较好地提高土壤中的氮的有效性，更好地协调土壤供氮能力。

Regulation of soil fixed ammonium and soluble N through combined application of N fertilizer and manure

[Objectives]As the temporary storage pools of fertilizer nitrogen (N), soil fixed ammonium (FA) could subsequently release N for plant uptake. Soil soluble N (SSN-soil soluble organic N, SSON; soil mineral N, SMN) are the important sources of soil FA, therefore, it is imperative to study the effects of combined application of N fertilizer and manure on the dynamics of soil FA and soil soluble N and their relationship under the greenhouse cultivation.[Methods]N application rates of: 0, 187.5, 375.0 and 562.5 kg/hm2(recordered as N0, N1, N2 and N3), 75000 kg/hm2 of manure fertilizer combined with N0, N1, N2, and N3 were sep up in a field plot experiment under the greenhouse cultivation.[Results]Fertilizer application significantly increased SSN and FA in the 0–30 cm depth (P < 0.01). In general, N2 treatment demonstrated the highest values for SMN, SSON and FA under no manure treatments. MN2 and MN3 treatments had the highest values for SMN, SSON and FA under the N fertilizer and manure combined application. There were no significant differences for soil FA with different nitrogen fertilizer rates (P > 0.05). Soil FA was significantly and positively correlated with SMN during the growing season, except for 20–30 cm interval during the harvesting period (P < 0.05). Significant and positive correlation was also existed between soil FA and SSON in some soil layers (P < 0.05).[Conclusion]Soil fixed ammonium and soluble N pools significantly affect the N immobilization and release. The appropriate rate of N fertilizer and manure application (M: 75000 kg/hm2; N2: 375.0 kg/hm2) could modulate the soil N supply more effectively in greenhouse cultivation.