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

Abstract

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 (2014 and 2015), between March and August. The experiment was arranged in a randomized block design. Treatments consisted of five nitrogen 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 assessed traits. In 2014, the highest results were achieved by the respective nitrogen and potassium doses: 145.02 and 148.32 kg ha -1 for shoot 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 significant results were identified, while nitrogen doses showed a linear effect on shoot and spike dry weights, potassium rates revealed such effect on grain yield. Although nitrogen showed a higher response in terms of dry weight for shoot and spikes, potassium induced the largest increases in productivity. Thus, for greater efficiency of fertilization, a careful analysis of the level of soil fertility, the expected productivity and the technological level employed is necessary. It should be emphasized that the management of fertilization has specificities every year, requiring constant adaptation.Keywords: BRS 254 wheat; Cerrado wheat production; nitrogen-potassium ratio; nitrogen and potassium fertilizations; Triticum aestivum. Abbreviations: ANOVA_variance analysis; CAPES_coordination for improvement of higher education personnel; CEC_cation exchange capacity; CNPq_national council for scientific and technological development; EMBRAPA_brazilian agricultural research company; ET o _reference evapotranspiration; FAO_ food and agriculture organization of the united nations; FAPEMAT_research support foundation of the state of mato grosso; FTE_fritted trace elements; KCL_potassium chloride; O.M._organic matter; SAS_statistical analysis software; SB_sum of bases; SDW_shoot dry weight; SpDW_spike dry weight; V_base saturation; WY_wheat yield;