Abstract

Wastewater reuse has increasingly become a sustainable alternative to the efficient use of water as well as the mitigation of the negative environmental impacts generated by the release of the water to the environment in an indiscriminate way. Thus, it is very important to know and evaluate the physiological variables of gas exchanges of plants cultivated with these waters, in order to obtain precise answers their effects on plant physiology. The present study aimed to evaluate the gas exchange of yellow capsicum cultivated in soil fertilized with human urine and cassava wastewater. The experiment was conducted in a protected environment at the Federal University of Campina Grande, Campina Grande - PB. A completely randomized design with eight treatments and five replications was used. The treatments were cattle manure (T1); NPK (T2); human urine treated (T3); cassava wastewater (T4); (T3)+(T4); 2x(T3); 2x(T4); 2x(T3+T4). The volumes of the biofertilizers were defined according to the nitrogen and potassium contents of urine and cassava wastewater, respectively. At 15 and 30 days after transplanting, the variables of gas exchange, the efficient use of water and the instantaneous efficacy of carboxylation were evaluated. The data were submitted to Tukey test at 5% probability. The results indicated that there wasn’t statistical difference for efficient use of water (UEA) evaluated at 30 DAT.The treatment 5 provided the best results in relation to gas exchange, for the variables internal concentration of CO₂ (Ci), net assimilation rates of CO₂ (A), stomatal conductance (gs), leaf transpiration (E), higher efficiency of water use (UEA) and instantaneous carboxylation efficiency at 15 DAT, so for 30 DAT the biofertilizer that provided the best results was the T4 treatment, although there weren’t significant statistical differences among the treatments for (UEA), except for of T5.

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