Resumo

LAZO, José Vicente; ASCENCIO, Jocelyne; UGARTE, Jorge  e  YZAGUIRRE, Luis. Effect of Humusbol (double humate of potassium and phosphorus) on corn growth in vegetative phase. Bioagro [online]. 2014, vol.26, n.3, pp.143-152. ISSN 1316-3361.

The effect of a liquid organic amendment, consisting mainly of humic and fulvic acids, on the vegetative growth of corn plants was evaluated under greenhouse conditions. The experiment was performed as a completely randomized design with four replications and the following six treatments: Humusbol applied to soil at doses of 5, 6, 7 and 8 L·ha^-1 + 1 L in 200 L of water to foliage; a commercial check (humus from earthworms) at doses of 5 L·ha^-1 applied to the soil + 4 L in 200 L of water to the foliage, and an untreated check. The plants were grown in plastic pots opaque to light, filled with 8 kg of fertilized sandy loam soil (120, 50, and 40 kg·ha^-1 N- P₂O₅ -K₂O ). In each pot, one maize plant, hybrid H-2020, was grown. The soil treatments were applied 14 days after emergence, and treatments to foliage 14 days thereafter. The variables measured per plant were photosynthetic rate, relative chlorophyll content (SPAD), number of leaves, plant height, stem diameter, total leaf area, and dry biomass of roots and aerial organs. Results indicated that maize plants treated with the liquid organic amendment, had higher values for all tested morphometric variables as compared to the commercial and untreated checks. No significant differences were found for photosynthetic rates. Results suggest that the liquid organic amendment greatly stimulated the corn plant growth.

Palavras-chave : Humic and fulvic acids; chlorophyll; soil amendments; humic substances.

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