Morphological development and yield of wheat irrigated under nitrogen and potassium fertilization in Cerrado Oxisol

摘要

This study aimed at assessing the effects of nitrogen-potassium interaction on dry matter and grain yield of irrigated wheat(Triticum aestivum L.) grown in the Brazilian Cerrado. The experiment was conducted for two consecutive cropping seasons (2014and 2015), between March and August. The experiment was arranged in a randomized block design. Treatments consisted of fivenitrogen and five potassium doses in a factorial scheme (5×5). The analyzed variables consisted of the shoot and spike dry weights,and grain yield. In both years (2014 and 2015), isolated effects of nitrogen and potassium doses were observed on the assessedtraits. In 2014, the highest results were achieved by the respective nitrogen and potassium doses: 145.02 and 148.32 kg ha -1 forshoot dry weight, 133.79 and 139.85 kg ha -1 for spikes, and 119.14 and 138.83 kg ha -1 for grain yield. Yet in 2015, no significantresults were identified, while nitrogen doses showed a linear effect on shoot and spike dry weights, potassium rates revealed sucheffect on grain yield. Although nitrogen showed a higher response in terms of dry weight for shoot and spikes, potassium inducedthe largest increases in productivity. Thus, for greater efficiency of fertilization, a careful analysis of the level of soil fertility, theexpected productivity and the technological level employed is necessary. It should be emphasized that the management offertilization has specificities every year, requiring constant adaptation.