Utilização de diferentes tipos e doses de biocarvão na relação solo/planta em milho

Abstract

In the context of meeting the growing demand for food and mitigating negative effects of anthropic action on the environment, new alternatives must be urgently proposed in order to address the issues faced. The objective of the present work was to determine the physiological, nutritional and productive responses of the corn crop, as well as the chemical qualities of the soil, after application of different sources and doses of biochar from environmental passives incorporated into the soil. The experiment was conducted in an area belonging to the Federal University of Ceara and linked to Embrapa Tropical Agroindustry, located in Fortaleza, Ceara. The design was completely randomized and the factorial arrangement of 2 x 5 + 2, using two treatments (sewage sludge biochar and green coconut shell), five doses (10, 20, 30, 40 and 50 t ha-1). ), 2 additional treatments (treatment without fertilizer and with mineral fertilization) and 5 repetitions, totaling 60 experimental units. Growth and yield parameters were evaluated: plant height, stem diameter, leaf area and dry mass (shoot, root, reproductive part and total mass); physiology: photosynthesis, stomatal conductance, transpiration, instantaneous water use efficiency, instantaneous carboxylation efficiency, relative chlorophyll index, chlorophyll a, chlorophyll b, carotenoids and total chlorophyll content; mineral nutrients in plants and soil: macronutrient contents: N, P, K, Ca, Mg and S, micronutrients: Cu, Fe, Mn and Zn and other elements Na, Al, Cr, Ni, Pb, Se, Cd, Hg and As; Soil chemical performance after addition of biocarbons: pH, electrical conductivity, organic matter content and organic carbon. In the results it was verified that the increase of the applied doses in the soil improved the efficiency of the plant photosynthetic apparatus; when comparing the maximum and minimum doses of application of both biocarbons, increment of 43.06%, 19.63%, 15.41% and 17.71% regarding the respective variables: leaf area, dry mass of shoot, mass and dry mass of the reproductive part and 38.47%, 38.25%, 67.07% and 39.01% for the respective accumulations of macronutrients in the shoot: N, P and K, being the first value referring to green coconut shell biochar treatment and the second to sewage sludge biochar treatment; soil pH increase. The different doses and types of biochar influenced both the metabolism of the plant and the performance of soil chemical qualities.