Chemical evaluations of lettuce leaves grown under the residual effect of soil fertilized with organic compost

An experiment was carried out from July to September 1996, in Mossoró, Rio Grande do Norte State, Brazil, to evaluate the effect of organic compost on chemical characteristics of lettuce leaves at the second successive cultivation. The experimental design was of randomized complete blocks in a 5 x 2 factorial scheme with four replications. The first factor consisted of doses of organic compost: 0; 40; 80;120 and 160 t ha-1 and the second factor consisted of the presence or absence of mineral fertilizers: 300; 500 and 150 kg ha-1 of ammonium, super phosphate simples and potassium chloride, respectively. The brute protein, phosphorus, potassium and magnesium contents in lettuce leaves increased in function of doses of organic compost. There was no significant interaction between doses of organic compost and doses of mineral fertilizer on the evaluated traits.

Lactuca sativa L.; postharvest; mineral fertilizer; organic fertilizer