Nitrogênio orgânico e químico na cultura da alface

Abstract

Organic residues can replace chemical fertilizers, showing all essential nutrients for plants improving the physical, chemical and biological soil characteristics. We evaluated the efficiency of organic and chemical nitrogen in the nutrition and production of lettuce. This experiment was carried out in a greenhouse with a 5-liter pot. The experimental design was randomized blocks with six treatments and five repetitions in two cycles of green-leaf lettuce from Lucy Brown variety, as defined: T0 -without nitrogen fertilization; T1 -0.54 g of N (urea) per plant divided into three times (7, 14 and 28 days of transplant), T2 -0.27 g of N (organic compound) and 0.27 g of N (urea) divided into three times per plant (7, 14 and 28 days of transplant); T3 -0.54 g of N (organic compound) per plant; T4 -0.81 g of N (organic compound) per plant; T5 -1.08 g of N (organic compound) per plant. T1, T2, and T3 treatments represent 100% of the N recommendation for lettuce and the T4 and T5 treatments represent 150 and 200%, respectively. In the first cycle of lettuce, the T4 and T5 treatments with higher amounts of organic compounds led to an increase of green mass production comparing to other treatments. In the second cycle of lettuce, all treatments that received organic fertilization obtained a higher green mass production than treatments with no compound.