不同氮磷钾水平对生菜产量及体内养分的影响

采用水培试验，对生菜（Lactuck sativ．crispa）在不同氮、磷、钾水平条件下的产量及其植株氮、磷、钾的质量分数进行了研究．结果表明，氮、磷、钾对提高生菜的产量有明显的作用，在0、1／2、1剂量水平下，随着氮、磷、钾用量的增加，生菜产量也随之显著增加．氮、磷、钾之间存在着相互促进吸收的作用，随着氮素水平的增加，植株中磷和钾的质量分数及植株对磷和钾的吸收量也显著增加；磷素水平的增加也使植株中氮和钾的质量分数和植株对氮和钾的吸收量有所增加；而钾素水平的增加虽然也使植株对氮和磷的吸收量有所增加，但对植株中氮和磷的质量分数影响不大．进一步分析表明，氮、磷、钾三要素中任何一种元素的缺乏都会影响生菜的生长以及对其他养分的吸收和利用，氮、磷的增产效果比钾素明显，生菜对钾素的需求量也相对较低.

Effects of different N, P and K levels on yield and nutrient content in Lettuce

Hydroponic culture experiment was carried out to study the yield and the content of N, P and K in lettuce under different N, P and K conditions. The results indicated that N, P and K played an important role in increasing the yield of lettuce, which increased significantly with the increasing of the N, P and K application among 0 dosage, 1/2 dosage and 1 dosage of completely nutrient solution conditions. In addition, the significant effect in inactive promotion uptake was found among N, P and K, the content of P and K and the quantity of its absorption by plant increased significantly with increasing of the N application; Also, the content of N and K and the quantity of its absorption by plant increased significantly with increasing of the P application. However, the increasing of K application could increase the quantity of N and P uptake to plant inereased, though the content of N and P in plant was not affected significantly. Thus, among the N, P and K, the shortage of any one would affect the growth of lettuce and the absorption and utilization of other elements. In view of the yield promotion, N and P had more significant effect than K. Moreover, the demand of K for lettuce was relatively low.