热带地区夏季水培小白菜营养液浓度的研究

为了研究热带地区夏季(4月至6月)水培小白菜适宜的营养液浓度,进行了2个试验。①研究了定植后营养液的5个不同浓度处理(华南农业大学叶菜B配方的1/4倍、1/2倍、3/4倍、1倍和5/4倍浓度)对水培小白菜生长和品质的影响。结果表明,3/4倍的营养液浓度处理下的小白菜单株产量为11.88 g,硝态氮含量为1 792.25 mg/kg,维生素C的含量为0.037 mg/g,综合指标在各处理中表现最优。②研究了收获前7 d营养液不同浓度处理〔华南农业大学叶菜B配方的1/4倍、1/2倍、3/4倍、1倍和清水(CK)〕对水培小白菜生长和品质的影响。结果表明,收获前7 d用1/4倍营养液浓度处理下的小白菜单株产量为16.20 g/株,硝态氮含量为1 300.79 mg/kg,维生素C的含量为0.035 mg/g,综合指标在各浓度处理中表现最优。在热带地区夏季,用华南农业大学叶菜B配方进行小白菜水培时,可在定植后前期用3/4倍的营养液浓度进行培养,收获前1周换用1/4倍浓度的营养液进行培养最为经济有效。

A Study on Nutrient Solution Concentrations of Hydroponic Pakchoi Cabbage in Summer in Tropics

In order to study the appropriate solution concentrations of the hydroponic pakchoi in summer（from April to June） in tropics,two experiments were carried out.The first experiment was done to study the effects of five different nutrient solution concentration treatments（1/4,1/2,3/4,1 and 5/4 units of South China Agricultural University nutrient solution formula B for leaf vegetables） on the growth and quality of hydroponic pakchoi after transplanting.The results showed that the single plant yield of the 3/4 unit concentration was 11.88 g,the nitrate nitrogen content was 1 792.25 mg/kg,the Vintamin C content was 0.037 mg/g.The aggregative indexes were the number one in all the concentration treatments.The second experiment was done to study the effects of five different nutrient solution concentration treatments（1/4,1/2,3/4,1 units of South China Agricultural University nutrient solution formula B for leaf vegetables and water CK） on the growth and quality of hydroponic pakchoi for 7 days before harvesting.The results showed that the single plant yield of the 1/4 unit concentration was 16.20 g,the nitrate nitrogen content was 1 300.79 mg/kg,the vintamin C content was 0.035 mg/g.The aggregative indexes were the number one in all the concentration treatments.From the two experiments,it was concluded that the suitable appropriate solution concentration of hydroponic pakchoi was the 3/4 unit concentration in the earlier stage of growth,to change the solution concentration to 1/4 unit concentration to culivate for 7 days before harvesting in summer in tropics,so the South China Agricultural University nutrient solution formula B for leaf vegetables for hydroponic pakchoi was evaluated as economical and practical one.