Influence of the application of fulvic acid on seedling root growth and yield in lettuce

ABSTRACT Humic substances are used in agriculture to promote plant growth, especially of the root system. The aim of this work was to evaluate the effect of applying different doses of fulvic acid on growth and productivity in the Raider Plus cultivar of the lettuce. The experimental design was completely randomised, with five treatments of fulvic acid 0, 1, 2, 4 and 8 ml L-1 and four replications, applied when transplanting. Two experiments were conducted simultaneously; one carried out in a greenhouse, where the fresh and dry weights of the shoots and roots, and the length and volume of the roots were evaluated. The other experiment was carried out in the field, where the fresh and dry weight of the shoots, the number of leaves, length of the stem and average head circumference were evaluated at the end of the cycle. The application of different doses of fulvic acid promoted growth in the lettuce plants, especially in the root system. The emission of roots, mainly of smaller diameter, was found at the higher concentrations of fulvic acid. The number of leaves and average head circumference expressed a response to the concentrations of fulvic acid.

摘要 腐殖质在农业生产中被用于促进植物生长，尤其对根系发育效果显著。本研究旨在评估不同施用量黄腐酸(fulvic acid)对Raider Plus品种生菜生长与产量的影响。实验采用完全随机设计，设置0、1、2、4、8 ml·L⁻¹共5个黄腐酸施用量处理，4次生物学重复，于移栽时施用。本研究同步开展两项试验：一项在温室中进行，测定地上部与根系的鲜重、干重，以及根系长度与体积；另一项在大田开展，于生育周期结束时测定地上部鲜重、干重、叶片数、茎长及平均叶球周长。结果表明，不同浓度黄腐酸施用量均可促进生菜植株生长，尤以根系生长效果突出；高浓度黄腐酸处理下，小直径细根的萌发更为明显；叶片数与平均叶球周长随黄腐酸浓度变化呈现显著响应趋势。