氮肥与有机肥配施对设施土壤可溶性氮动态变化的影响

【目的】在氮肥与有机肥配施条件下,研究设施番茄生长期内土壤可溶性氮(矿质氮和可溶性有机氮)的动态变化,评估可溶性氮在设施土壤中的作用,为设施土壤的合理施肥提供理论参考。【方法】以连续两年不施肥(CK)、不同施氮量(N0、N1、N2、N3)、单施有机肥(M)以及不同氮量配施有机肥(MN0、MN1、MN2、MN3)的设施番茄栽培的田间小区试验的方法,研究氮肥与有机肥配施以及不同施氮量对番茄生长期、休耕期土壤可溶性氮动态变化的影响。【结果】在番茄生长期,与施用氮肥处理相比,氮肥与有机肥配施处理均能够显著增加0—30 cm土层土壤矿质氮和土壤可溶性有机氮的含量(P0.01),特别是提高了矿质氮的含量。土壤矿质氮和土壤可溶性有机氮均表现出比较大的动态变化,总体来说,土壤矿质氮和土壤可溶性有机氮含量均在第一穗果膨大期最高,在第二穗果膨大期土壤矿质氮含量大于可溶性有机氮含量,而在收获期土壤可溶性有机氮含量大于矿质氮含量,且在整个生长季内土壤矿质氮和土壤可溶性有机氮含量之间均有显著的正相关关系(P0.05)。在休耕期(番茄收获后60 d),与施用氮肥处理相比,氮肥与有机肥配施处理均能显著增加0—50 cm土层土壤矿质氮和0—10 cm土层土壤可溶性有机氮的含量(P0.05);在0—50 cm土层内,土壤矿质氮和土壤可溶性有机氮的含量均随土层深度加深呈逐渐下降趋势,且在20—40 cm处有明显的累积。此外,不管是在番茄生育期还是在休耕期,总体上来看,不施有机肥处理下,土壤矿质氮和土壤可溶性有机氮的含量均以N2处理的含量为最高,而且土壤可溶性有机氮在可溶性氮中占有更大的比例;而在氮肥与有机肥配施处理中,MN2和MN3处理的土壤矿质氮和土壤可溶性有机氮含量最高,而且在可溶性氮库中以土壤矿质氮为主。【结论】本试验条件下,适量氮肥与有机肥配施能够更好协调和改善设施土壤中可溶性氮的供应状况。

Effect of Combined Application of Nitrogen Fertilizer and Manure on the Dynamic of Soil Soluble N in Greenhouse Cultivation

【Objective】 A greenhouse cultivation experiment was conducted to study the effect of different short-term fertilization treatments on the dynamic of soil soluble N (soil mineral N and soil soluble organic nitrogen) during the tomato growth period, and to evaluate the soil soluble N which plays an important role in greenhouse soils. The results would provide a scientific basis and practical guidance for rational fertilization. 【Method】 We report a comparative study in which under different N management (different rate of N, combined with or without manure fertilizer) in the greenhouse cultivation. We observed the effect on dynamic variation during the tomato growth period and in the 0-50 cm soil layers at the fallow period of soil mineral nitrogen (SMN) and soil soluble organic nitrogen (SSON) contents. 【Result】 The combined application of N fertilizer and manure treatments significantly increased SMN and SSON contents compared to N fertilizer treatments in the 0-30 cm soil layers, and more amplification occurred in SMN (P＜0.01). There was a large dynamic during the tomato growth period, in general, SMN and SSON contents were highest during the first ear fruit period, and the SMN content was higher than the SSON content during the second ear fruit period, while the SSON content was higher than the SMN content during the harvest period; also significant positive relationships were found between SMN and SSON throughout the tomato growing season (P＜0.05). N fertilizer plus manure increased the content of SSON in the 0-10 cm layer and SMN in the 0-50 cm layer significantly compared to N fertilizer treatments during the fallow period; the SMN and STSN were decreased with the soil deep, and accumulation occurred in the 20-40 cm soil layer (P＜0.05). In addition, whether through the tomato growth period or the fallow period, in the no-manure treatments, the highest content of soil mineral N and soil soluble organic nitrogen occurred in the N2 treatment, and SSON was higher in the soil soluble N pool. But in the N fertilizer plus manure treatments, they were higher in the MN2 and MN3 treatments than the others, and SMN was a larger proportion overall, while SSON accounted for a large part of soil total soluble nitrogen (STSN).【Conclusion】 The conclusion is that the medium rate of N fertilizer plus manure has a high ability to modulate the soil soluble N supply in a greenhouse condition.