Dados do Trabalho

Título

RESIDUAL DOSES AND ALTERNATIVE POTASSIUM’ SOURCES AT DIFFERENT TIMES OF APPLICATION IN CORN CROP

Resumo

Corn is among the three most planted cereals in the world and low soil fertility is one of the main factors responsible for low corn productivity. The function of potassium (K) is in the regulation of water flow, opening and closing of stomata and activating several enzymes of hormones and photosynthesis. The present study aimed to verify the residual effect of application times and doses of alternative sources of potassium (Potasil “phonolite” or Ekosil “Hydrothermalized phonolite/Potassic Rock”), in corn crop in no-tillage system in Cerrado. The experiment was carried out at the Farm of Teaching, Research and Extension of UNESP, in Selvíria-MS. The soil in the experimental area is classified as Dystrophic Red Oxisol. The experimental design was carried out in randomized blocks, in a 2x4x3 factorial scheme, as follows: two application times (at the time of sowing and 30 days before soybean sowing), four residual potassium doses (0, 40, 80 and 120 kg ha-1 of K2O) and three sources of potassium (KCl, Potasil “Phonolite” and Ekosil “Hydrothermalized Phonolite/Potassic Rock”), with four replications. The treatments with potassium fertilization were applied by broadcast and without incorporation into the soil. For the K accumulation in the straw, the best dose was 120 kg ha-1 of K2O with early fertilization at sowing time. For the accumulation of Na in straw, there was not significant difference. In the accumulation of Ca, the highest values ​​were found in fertilization at sowing, becoming available for the crop, we can observe that the potassium source maintains a greater accumulation of Ca when compared to the other doses. For K accumulation, the higher the dose, provides the greater the accumulation of this nutrient in the straw, making it available for the next crop. Ekosil fertilizer is an alternative that contains less Na. For greater Ca accumulations, the application potassium sources must be made at sowing.

Palavras-chave

Zea mays; nutrients accumulation in straw; potassium fertilization; calcium; sodium.

Instituição financiadora

Fundação de Ensino, Pesquisa e Extensão de Ilha Solteira