【摘要】 通过5水平田间小区试验,研究了海南旱地蕹菜对尿素氮的吸收利用情况。结果表明,在磷肥(P2O5)、钾肥(K2O)施用量为60、450 kg/hm2条件下,蕹菜产量与施氮量之间的关系符合一元二次多项式Y=29.412+214.438 X-398.736 X2(F=112.4**),蕹菜最高产量施氮量为450 kg/hm2。在该试验条件下,从氮肥施用的经济效益、干物质积累情况、总氮吸收量和氮肥利用率综合考虑,旱地蕹菜最佳氮肥施用量为300 kg/hm2。随着尿素氮用量的增加,蕹菜叶片硝酸还原酶活性下降,蕹菜硝酸盐含量增加,叶柄和茎部是积累硝酸盐的主要部位。在适宜的氮肥用量条件下,蕹菜的硝酸盐含量符合WHO/FAO规定的新鲜蔬菜硝酸盐含量卫生标准。更多还原

【Abstract】 A field trial was made at 5 N-levels to observe nitrogen uptake and utilization in swamp cabbage. An equation was developed to relate the yield of swamp cabbage with the application rate of fertilizer under the conditions that the P fertilizer (P2O5) and K fertilizer (K2O) were applied at a respective rate of 60 kg/ha and 450 kg/ha: Y= 29.412 + 214.438X- 398.736X2 (F = 112.4**). The optimum application rate of N fertilizer for the highest yield of swamp cabbage was 300 kg/ha. The nitrate reductase activity in leaves was decreased and the nitrate content of swamp cabbage increased with the application rate of N fertilizer. The content of nitrate in swamp cabbage was in conformity with the hygiene standard of WHO/FAO when optimum rate of N fertilizer was applied.更多还原