Cultivo de gergelim irrigado sob diferentes fontes e doses de potássio.

Abstract

The reuse of waste for plant nutrition has been widely discussed and evaluated, due to the minimization of incorrect disposal and environmental pollution and degradation, in addition to the economic benefits that can provide producers. Thus, cassava wastewater, which is a liquid effluent generated from the processing of cassava in flour houses, has great potential to be used as fertilizer on agricultural crops. In view of the above, the present study aimed to evaluate the effect of the application of sources (organic and mineral) and doses of potassium on the physiology, growth and production of irrigated sesame cultivars. The study was conducted under greenhouse conditions, in Campina Grande, PB, using an experimental design entirely randomized and factorial scheme (3×4×2) with three sesame cultivars (BRS Anahí, BRS Morena and BRS Seda), four increasing doses of potassium (40, 60, 80 and 100 kg ha-1) and two sources of potassium (cassava wastewater and potassium chloride), with three repetitions and one plant per plot. The treated cassava wastewater increased the growth of sesame cultivars at 30 and 60 days after sowing. Increasing doses of potassium were responsible for increasing the internal CO2 concentration and reducing the instantaneous carboxylation efficiency. The dose of 40 kg ha-1 using potassium chloride resulted in higher instantaneous water use efficiency of sesame cultivars. The BRS Seda cultivar had the best production results when compared to the other cultivars, especially when subjected to cassava wastewater fertilization. The accumulation of dry biomass was also favored by the use of cassava wastewater and BRS Morena stands out in relation to the other cultivars. Considering the results of this study, the application of doses of cassava wastewater as a source of potassium between 60 and 80 kg ha-1 can supply the potassium demand of sesame cultivars. Cassava wastewater is a potential source of organo-mineral fertilizer for sesame cultivation.