不同氮磷钾组合对莴笋产量和品质的影响

盆栽试验研究了不同氮磷钾组合对莴笋产量及品质的影响。结果表明:不同处理间莴笋产量有显著差异,以N3P2K1>N3P1K2>N2P2K2>N2P3K1>N2P1K3,中量供N水平下高量配施P或K均表现为低产效应。莴笋叶硝酸盐含量以N2P3K1处理最高,N3P1K2和N3P2K1处理最低,茎的硝酸盐含量以N2P1K3>N3P1K2>N2P2K2>N2P3K1>N3P2K1。在三要素组合处理中,钾有利于降低叶片硝酸盐含量,而磷有利于控制茎中硝酸盐累积。莴笋的Vc含量以叶>茎,还原糖和氨基酸含量则是茎>叶。N3P2K1、N3P1K2和N2P2K2处理对莴笋叶、茎的营养品质(Vc、还原糖和氨基酸含量)效应较好,其中N3P1K2处理对莴笋叶品质的综合效应最佳,N3P2K1处理莴笋茎品质的综合效应最佳。5个氮磷钾配比对莴笋产量及叶、茎的品质效应以N3P2K1、N3P1K2和N2P2K2处理较优。

Effect of the Combined Application of N, P and K on Yield and Quality of Lettuce

In potted experiment,the effect of the combined application of N,P and K on yield and quality of lettuce was studied.There was a significant difference in yield among five treatments,which was in the order of N_3P_2K_1>N_3P_1K_2>N_2P_2K_2>N_2P_3K_1>N_2P_1K_3.When nitrogen was at the middle level(N_2),there was a reducemect of yield both for higher level of phosphor(P_3) and potassium(K_3).The highest concentration of nitrate in lettuce leaf was found in treatment N_2P_3K_1,and the lowest was in N_3P_1K_2 and N_3P_2K_1.In stem the nitrate concentration was in the order of N_2P_1K_3>N_3P_1K_2>N_2P_2K_2>N_2P_3K_1>N_3P_2K_1.Among the three nutrient factors,it was the potassium(K) and the phosphors(P) that could decrease the nitrate concentration in lettuce leaf and decrease the nitrate accumulation in lettuce stem,respectively.There was higher concentration of Vc in leaf of lettuce than stem,but the concentration of reductive sugar and amino acid was higher in the latter than the former.There was an obvious effect of nitrogen,phosphors and potassium combination on the nutrient quality(Vc,reductive sugar and amino acid) in leaf and stem of lettuce.There was a better effect of nutrient combination on the nutrient quality of lettuce in N_3P_2K_1,N_3P_1K_2 and N_2P_2K_2,and the best,in N_3P_1K_2 and N_3P_2K_1 in leaf and stem,respectively. Among five treatments of the combination,the higher yield and better quality for lettuce were obtained in N_3P_2K_1,N_3P_1K_2 and N_2P_2K_2.