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本试验采用好气培养法研究了商品有机肥及蔬菜残体在菜地土壤中的氮素矿化 ,结果表明 :土壤中施入尿素、有机肥和蔬菜残体的处理 ,7- 14天后 NH4 + - N降低到对照水平 ,之后各处理的 NO3- N的累积量具有显著差异 ,35天时 ,NO3- N累积量的次序为 :尿素 +菜花残体≈尿素 +苋菜残体 >尿素+有机肥 >尿素 >有机肥 >0— 30 cm土壤 >30— 6 0 cm土壤。0— 30 cm土壤累积矿化量远高于 30— 6 0 cm,矿化速率也是如此 ,其累积量与培养时间可以用一元二次方程拟合。本研究所用有机肥 C/N比为 2 5∶ 1,其单独添加或与尿素一起添加时 ,前期均表现为无机氮的净固定过程 ,2 8— 33天以后才释放无机氮。尿素 +菜花残体和尿素 +苋菜残体处理的 Nmin(铵态氮 +硝态氮 )都高于尿素处理 ,说明这两种 C/N较低的蔬菜残体都释放了相当量的无机氮 ,表现为氮的净矿化作用。
In this study, aerobic culture was used to study the mineralization of commercial organic manure and vegetable residues in vegetable soil. The results showed that treatment with urea, organic manure and vegetable residues in the soil, after 7 to 14 days NH4 + - N decreased to the control level, and the NO3 - N accumulation of each treatment had significant difference after 35 days. The order of NO3 - N accumulation was urea + cauliflower ≈ urea + amaranth> urea + organic fertilizer> Urea> Organic fertilizer> 0-30 cm soil> 30-60 cm soil. The cumulative mineralization in the 0-30 cm soil is much higher than 30-600 cm, as is the mineralization rate, and the cumulative amount and incubation time can be fitted by a one-quadratic equation. The C / N ratio of organic manure used in this study was 25: 1. When added alone or together with urea, the former showed net fixation of inorganic nitrogen, and inorganic nitrogen was released after 8-33 days. Nmin (ammonium nitrogen + nitrate nitrogen) of urea + cauliflower residues and urea + amaranth residues were higher than urea treatment, indicating that both of the lower C / N vegetable residues released a considerable amount of inorganic nitrogen , Showing the net mineralization of nitrogen.