Soil water retention, physiological characteristics, and growth of maize plants in response to biochar application to soil

Abstract

Studies on biochar application in agriculture are broad, but the effects are variable and depend on the type of plant, biochar properties, and application rate, as well as some soil characteristics and environmental conditions. This study aimed to assess the effect of applying different doses of biochar with two particle sizes on the physical and chemical characteristics of a Typic Haplustox, sandy loam, and on the growth and physiological characters of maize plants, under two soil moisture conditions. The study was conducted in a greenhouse, using two biochar particle sizes (2.0−0.5 and < 0.5 mm), at six doses (0, 5, 10, 20, 40 and 60 g kg−1) and two water conditions (with and without drought stress). The plant characters assessed were height, stem diameter, leaf area, shoot fresh and dry weight, and nutritional status. Leaf relative water content, photosynthesis, and stomatal conductance were evaluated under drought stress. The soil attributes studied were density, porosity, water retention curve, and hydrophobicity, in addition to chemical characterization. There were no statistical differences between the two biochar particle sizes, except for bulk density and microporosity. Under adequate water conditions, and two doses of biochar applied to the soil increased photosynthesis, stomatal conductance, and leaf relative water content in the sewn corn. In the soil, biochar raised water retention and the micropore/macropore ratio and reduced bulk density, in addition to improving fertility. High biochar doses improved soil fertility as well as plant nutritional status and development. The increased water retention as a consequence of biochar amendment was not sufficient to overcome drought stress problems in the soil.