Agronomic performance of lettuce at different amounts and decomposition periods of fresh scarlet starglory

Abstract

The objective of this study was to evaluate the agronomic performance of lettuce under different amounts and decomposition periods of fresh scarlet starglory incorporated into the soil. The experimental design was a randomized complete block with treatments arranged in a factorial 4 x 4 + 4, with  three replications. The treatments consisted of the combination of four fresh scarlet starglory amounts incorporated into the soil (2.2; 4.4; 6.6 and 8.8 t ha^-1 of dry matter) with four decomposition periods (0; 10; 20 and 30 days before lettuce transplanting), plus four additional treatments (no fertilizer, 80 t ha^-1 of cattle manure, 80 t ha^-1 of cattle manure plus mineral fertilizer of 160 kg ha^-1 N, 60 kg ha^-1 P₂O₅ and 30 kg ha^-1 KCl and only mineral fertilizer with 160 kg ha^-1 N, 60 kg ha^-1 P2O5 and 30 kg ha^-1 KCl). The lettuce cultivar used was ‘Babá de Verão’. The incorporation of fresh scarlet starglory into the soil positively influenced the agronomic performance of lettuce, showing to be promising in the use as green manure. The highest productivity of the lettuce was obtained with 6.11 t ha^-1 of fresh scarlet starglory incorporated to the ground 20 days before lettuce transplanting. The yields of the lettuce fertilized with cattle manure or cattle manure and mineral fertilization were respectively 32.08 and 28.81% higher than the lettuce yield fertilized with 6.11 t ha^-1 of fresh scarlet starglory incorporated 20 days prior to its transplanting. The yield of lettuce fertilized with fresh scarlet starglory in the amount of 6.11 t ha^-1 at 20 days before transplanting was 3.08% higher than the productivity of lettuce with mineral fertilizer.