营养液铵硝比对砂培韭菜生长及硝酸盐含量的影响

目的]研究不同铵硝比营养液对韭菜生长及硝酸盐含量的影响。方法]2008～2009年,对日光温室内砂培的2年生韭菜,分别浇施总氮量相同、铵硝比为0∶100,15∶85,30∶70,45∶55和60∶40的营养液。结果]提高营养液铵硝比不仅大幅度降低了韭菜硝酸盐含量,而且显著地提高了春季韭菜的总产量。铵硝混合营养处理的韭菜硝酸盐含量极显著低于纯硝营养,铵硝比60∶40和45∶55处理的韭菜硝酸盐含量最低,均比纯硝营养降低了59.8%;铵硝比45∶55和30∶70处理的韭菜总产量显著高于纯硝营养,分别增产22.4%和14.0%。铵硝比对单茬韭菜产量的影响因收获时期不同而异,增铵对提高第1茬产量的作用最大、对第3茬无明显作用。结论]45∶55和30∶70是适合韭菜砂培的营养液铵硝比。

Effects of NH4+-N/NO3--N Ratio in Nutrient Solution on the Growth and Nitrate Content of Allium tuberosum Rottl.ex Spr. in Sand Culture

Objective]The study aimed to investigate the effects of NH4 + -N / NO3 --N ratio in nutrient solution on the growth and nitrate content in Chinese chive. Method]During 2008 -2009,the two-year-old Chinese chive seedlings were grown in sand culture under a solar greenhouse in Tianjin and irrigated respectively with different kinds of nutrient solution containing a constant concentration of total nitrogen with the NH4 + -N / NO3 --N ratios of 0∶100,15∶85,30∶70,45∶55 and 60∶40 on a molar basis. Result]The results showed that the nitrate content in Chi-nese chive leaves were decreased significantly by increasing NH4 + -N / NO3 --N ratio in nutrient solution,whereas the total yield of Chinese chive in spring were raised markedly. The nitrate content in Chinese chive leaves under treatments with combined ammonium and nitrate nitrogen supply were significantly lower than that of pure-nitrate treatment. The lowest nitrate content in Chinese chive leaves was attained while NH4 + -N / NO3 --N ratio was 60∶40 or 45∶55,both of them were 59. 8% lower than that of treatment with the NH4 + -N / NO3 --N ratio of 0∶100. The total yield of treatment with the NH4 + -N / NO3 --N ratio of 45∶55 and treatment with the NH4 + -N / NO3 --N ratio of 30∶70 were both significant higher than that of treatment with the NH4 + -N / NO3 --N ratio of 0∶100,which increased by 22. 4% and 14. 0% respectively. The influences of NH4 + -N / NO3 --N ratio in nutrient solution on the yield per mowing varied with the different mowing time. The first-cut yield was improved significantly by supplying with ammonium and the third-cut yield was not affected by the forms of nitrogen. Conclusion]The best NH4 + -N / NO3 --N ratios in nutrient solution in sand culture were 45∶55 and 30∶70.