氮素对大蒜产量影响和氮素供应目标值的研究

以地方品种金乡白皮蒜为试材，设6个施肥处理5个氮素水平，研究了氮素对大蒜产量的影响以及该条件下土壤氮素平衡等。结果表明：随着氮肥用量的增加大蒜的产量随之增加，MN1~MN4处理大蒜分别增产25.4%~40.2%。施氮240kg/hm2的MN3处理为该试验条件下的适宜用量。在大蒜整个生育期，土壤有机氮表观矿化量为N 134.5kg/hm2、有机肥净矿化量为N 34.2kg/hm2。大蒜在苗期、鳞芽花芽分化及蒜薹伸长期、鳞茎膨大期氮素的供应目标值应为N 158.6、128.0、211.6kg/hm2。随着氮肥用量的增加氮素的损失增加，MN1~MN4处理分别损失32.0%~40.4%。单位氮素投入所获得的收益随着氮肥施用量的增加逐渐减少，MN1~M4处理每投资1元钱的氮肥分别可获得97、67、51、35元的收益。大蒜施肥在注重产量的同时，也应兼顾环境和经济效益。

Effect of Nitrogen Fertilization and Optimal Application N Rates on Garlic Nutrition

The experiment was conducted in jinxiang county, Shandong province, and the selected variety was locally current ‘white garlic’. Six fertilization treatments and five N levels were designed to study the N effect on garlic yield and the nitrogen balance in the soil profile. The result showed that an increasing trend was observed for the garlic yield with the growing N application rates, and the growth rate ranged from 25.4 to 40.2％.It is indicated that treatment MN3(N 240 kg/ha) was the optimal N application rate under local condition. Results showed the apprant mineralized amount of soil organic N, and net mineralized amount of organic fertilizer were N 134.5 and 34.2 kg/ha respectively within the whole growing season. The optimum applying N rates of seedling stage, the phase of flower bud differentiation and garlic bolt elongation, bulb inflation phase were 158.6、128.0、211.6 kg/ha respectively. On the other hand, N loss increased (32.0~40.4%) accordingly with the growth of the N application rates, and the benefit per N rate reduced from 97 to 35 yuan per yuan input with the growing N application rates. A conclusion was conducted from the experiment that not only the yield should be thought a lot, but also the economic and environmental benefits be considered for the garlic fertilization.