Redução de haste verde e retenção foliar na soja em razão de maior disponibilidade de nitrogênio pelo tratamento de sementes

Abstract

Problems related to leaf retention and lack of uniformity in maturation in the soybean crop have been reported in various regions of Brazil, including the State of Parana, presenting a challenge to Brazilian researchers. Several hypotheses for this problem have been raised in regard to plants nutritional imbalance and intensification of the problem, but no definitive conclusion has been reached. A field experiment was carried out at the Copacol Experimental Farm in Cafelandia, PR, to evaluate how nitrogen availability via inoculation and the use of Co and Mo in seed treatment associated with fungicide and insecticide in soybean can minimize leaf retention and the green stem syndrome. Eight combinations of products were used in the treatment of soybean seed, considering the presence or absence of Co and Mo, inoculant and insecticide/fungicide. Leaf N content, the frequency of abnormal plants at the time of harvest, the proportion of pods with 0, 1, 2, 3 and 4 formed seeds, 1,000 seed weight, moisture content, impurity at harvest, and grain yield were evaluated. The use of Co, Mo and seed inoculation promotes an increase in leaf N in the soybean and reduces the number of abnormal plants, with a positive reflection on soybean yield components. The results showed the positive effect of better N nutrition of soybean on reduction of green stem syndrome and reaffirmed the need for the use of Co, Mo and seed inoculation.