不同施肥方案对华南地区菜心种植氨挥发损失的影响

为探明华南地区菜心种植过程中土壤的氨挥发损失规律,提出兼顾减少氨挥发且保证菜心产量的施肥方案,以广州市黄埔区菜地为研究对象,以菜心为试验材料,设置氮肥施用量处理为A组,设定A0（不施氮肥）、A1（337.5 kg·hm^-2）、A2（200 kg·hm^-2）、A3（140 kg·hm^-2）共计4种施氮水平;同时,设置施肥方式处理为B组,分别为沟施覆土（B1）、表面撒施（B2）和撒施后灌水（B3）共3组氮肥施用方式,开展正交试验。采用通气法对菜心菜地进行田间原位氨挥发测定,成熟期调查菜心产量。研究了不同施肥方案下土壤氨挥发情况和不同施肥方案对菜心产量的影响。结果表明：菜心种植过程中的氨挥发主要来自追肥,菜心追肥期间氨挥发量占全生育期氨挥发总量的60%~81%。氨挥发量与施氮量呈正比;不同施氮量在施肥初期,氨挥发速率均较高;相同施氮水平下氨挥发累积量呈现出表面撒施>沟施覆土>撒施后灌水。各施氮处理下,菜心产量无显著差异。研究表明,采用沟施覆土的施肥方式同时减少30%的施氮量对华南地区菜心产量无显著影响,但较常规施氮处理组A2B1和A2B2分别可减少氨挥发损失5.9 kg·hm^-2和29.3 kg·hm^-2。

Effects of different fertilization schemes on soil ammonia volatilization during flowering cabbage growth in south China

To evaluate soil ammonia volatilization and propose a fertilization scheme for reducing ammonia volatilization and ensuring flowering cabbage yield, an experiment was conducted in a typical vegetable field in Huangpu District of Guangzhou City. Using flowering cabbage as the test material, the nitrogen application rate was set as group A, and four nitrogen application levels were set, namely, A0(0), A1(337.5 kg·hm^-2), A2(200 kg·hm^-2), and A3(140 kg·hm^-2). Concurrently, the fertilization method was set as group B, and the three nitrogen application types were set, namely furrow covering soil(B1), surface spraying(B2), and post spraying irrigation(B3). An aeration method was used to measure the ammonia volatilization, and the Chinese cabbage yield was investigated at maturity and after maturity. Results showed that the ammonia volatilization was mainly from topdressing, accounting for 60%~81% of total ammonia volatilization during the whole growth period. Ammonia volatilization was positively proportional to nitrogen application. The ammonia volatilization rate was higher at the initial fertilization stage with different nitrogen applications. Under the same nitrogen application level, the ammonia volatilization accumulation showed the following order:surface fertilizer application > furrow soil covering > irrigation after spraying. Under each nitrogen application treatment, the yield of flowering cabbage was similar, without significant difference. Our results indicate that furrow soil covering application plus 30% reduction in nitrogen application rate has no significant effect on the yield of flowering cabbage in south China; At the same time, compared with the normal-using nitrogen treatment A2B1 and A2B2, it can also reduce the ammonia volatilization loss by 5.9 kg·hm^-2 and 29.3 kg·hm^-2,respectively.