There are reports of the use of cow urine in vegetable crops, but its efficacy needs to be confirmed. This work aimed to evaluate the effect of cow urine on the nutritional status of lettuce. The experiment consisted of 12 treatments arranged in a split-plot design and four randomized blocks. The ways of application (soil or foliar) were allocated in plots while the subplots consisted of solution concentrations (0.00; 0.25; 0.50; 0.75; 1.00 and 1.25 % v/v). It was applied 60 mL of solution/plant, divided into five applications of 5; 5; 10; 20 and 20 mL/plant, at 7, 14, 21, 28, and 35 days after transplant, respectively. The SPAD index was evaluated during the crop cycle. At harvest it was determined the head dry matter (HDM) and the contents of N, P, K, Ca, Mg, S, Na, Zn, Fe, Mn, Cu and B in the dry matter of leaves (DML), stems (DMS) and roots (DMR). For both ways of application, the SPAD index showed a linear increase in response to concentrations and a quadratic response over time. HDM presented a linear response to concentrations, with increasesof 25.9 and 35.4 % in the foliar and soil applications respectively. No effect of concentrations was observed on nutrient contents of DML and DMS. For DMR, with soil application, there was a maximum point for P and K and minimum for Fe and Mn; Na showed a linear increase in response to concentrations with foliar application. The effects of urinesolutions on lettuce growth may be caused by other factors than the amounts of nutrients present in the solutions.
Lactuca sativa L.; crop system; plant nutrition; organic agriculture
