Concentração foliar de nutrientes e produtividade de tomateiro cultivado sob diferentes substratos e doses de ácidos húmicos

Abstract

We evaluated the nutritional status and yield of tomato hybrid "Vênus", grown on substrates, with application of humic acids (AH) and fertigation. Four doses of AH (0, 20, 40 and 80 L-1 ha) and four substrates: S1 (coconut fiber (CF)), S2 (FC + carbonized coffee husk (CC) in the ratio 1:3), S3 (CF + CC - in the ratio 2:3) and S4 (CC) were evaluated following the randomized blocks design in factorial 4x4 scheme with four replications. The 35-day old seedlings were transplanted into plastic bags of 7 L. The humic acids were applied four times in eight-day intervals, and the first application was carried out eight days after transplanting. There was no significant effect of the treatments on the content of N, K and S in leaves and on non-marketable fruits yield. However, there was a significant effect of the substrates on the content of P, Ca, Mg and on the total and marketable fruit yield. Increasing doses of AH reduced linearly the content of B and Cu (on S1), but increased the content of Zn in leaves. Humic acid doses of 31 to 49 L ha-1 provided the highest contents of Fe, Cu, and the lowest content of Mn. The highest marketable yields were obtained using coconut fiber, with an average of 5.6 kg/plant, showing an average yield increase of 22.9%, 38.7% and 49.7% in comparison to S2, S3 and S4, respectively.