Carvão hidrotérmico: efeitos no solo e o feijoeiro submetidos à salinidade

Abstract

Soil salinity is a common soil problem in semi-arid climate environments. The hypothesis of this work is that hydrothermal charcoal produced from cashew bagasse mitigates soil salinity, induced with saline water irrigation, through the availability of nutrients, favoring the development of cowpea (Vignia unguiculata (L.) Walp.). One possibility to recover areas affected by salts is using hydrothermal coal, which has chemical characteristics that make it versatile and promote soil improvements. The objective of this work was to evaluate the effects of different doses of hydrothermal charcoal produced from cashew bagasse on the soil and on the development of cowpea subjected to irrigation with saline and non-saline water. The soil used in the experiment was collected in columns with preserved structure at the Vale do Curu Experimental Farm of the Federal University of Ceará (Pentecoste 3 CE). The 0-15 m layer of this column was removed and stirred with doses of 0, 5, 10, 20 and 40 Mg ha -1 of hydrothermal coal produced from cashew bagasse. The soil with hydrothermal charcoal and without hydrothermal charcoal was incubated for 30 days, after which cowpea seeds were planted. After germination, irrigation began with saline water and water without salts. The experiment lasted 30 days after germination. Soil analyzes were carried out to determine pH, ECes and Ca2+, Mg2+, Na+ and K+ contents. Analyzes of plant tissue were carried out to determine the macronutrients Ca, Mg, K and P. The experimental design was completely randomized, in a 5 x 2 x 4 factorial scheme, using hydrothermal charcoal in 5 doses, 2 different salinity levels in the water and 4 replications, totaling 40 experimental units, these were subdivided into four layers, totaling 160 samples. There were significant differences in the interactions between salinity values, layers and doses. The soil pH was in the optimal range (between 5.5 and 6.5) for nutrient availability, the concentrations of nutrients Ca, Mg and K increased compared to the soil before treatment, as well as Na. In plants, Ca was the nutrient in highest concentration, followed by Mg, K and finally, P. Given the results, hydrothermal charcoal was efficient in guaranteeing the development of cowpea, even when subjected to saline irrigation.