Nutrients’ content and accumulation by net melon plant cultivated with potassium and CO2 in the irrigation water

This paper aimed to evaluate the influence of carbonated water use and potassium doses on the nutrients’ content and accumulation by net melon plant. The experiment was conducted at the experimental area of the Department of Agricultural Engineering of ESALQ/USP, in Piracicaba, Sao Paulo, Brazil. Two greenhouses were used, where one applied four potassium doses (50; 150; 300; and 600 kg.ha-1 of K2O) through drip irrigation water. Only in one of the greenhouses 301.8 kg.ha-1 of CO2 were applied through irrigation water, however, in a separate way from the potassium application. The experimental design adopted was that of randomized blocks in a factorial scheme with 4 replications, totaling 32 plots, each of them consisting of 13 plants. Data on the nutrients’ content at each time and the nutrients’ accumulation at the cycle end underwent variance analysis and, in case of a significant effect, the regression analysis was used to check the effect of potassium doses and Tukey’s test for comparing the effect of using CO2. One found out that CO2 application decreased the potassium and magnesium accumulation and, in general, caused an increase in the plants’ macronutrient content. Regarding the micronutrients, there was an increase in zinc accumulation at the melon plant’s shoot and the manganese and zinc content was higher in all the plant parts which received CO2 in the irrigation water