摘要
Organic food continues to increase in popularity worldwide.Similarly,hydroponic production of leafy greens is expanding globally and is an important component of the world's food supply.The purpose of this study was to evaluate the growth and quality of lettuce using six nutrient film technique(NFT)hydroponic systems.There were three treatments:organic fertilizer with or without a microbial inoculant and a conventional inorganic fertilizer as a control.The experiment was repeated over time.Results showed that the plants grown with organic fertilizer with additional microbial inoculant achieved similar shoot fresh and dry weight to those of the control,and dry weight was 17%higher than the organic fertilizer without inoculant.Nitrogen content in the shoot tissue of plants treated with organic fertilizer with inoculant was 10%and 24%greater than the control and the organic fertilizer without inoculant,respectively.However,when the organic fertilizer with inoculant was reused in a second experiment,shoot fresh and dry weight of plants in organic fertilizer with inoculant was lower than those in the control but were still higher compared to the organic fertilizer without inoculant.Additionally,electrical conductivity(EC)and pH of the organic fertilizer solutions fluctuated widely.Interestingly,relative chlorophyll content measured as SPAD and anthocyanin content in the leaf tissue increased in plants treated with organic fertilizer,regardless of inoculant,by 19%and 9%,respectively.
