Effect of biochar on physicochemical properties of a sandy soil and maize growth in a greenhouse experiment

Numerous studies have been conducted worldwide and more specifically in Brazil assessing the consequences of biochar amendments on the soil properties and on the agronomical production. The present study aimed to evaluate the effects of biochar of coffee residues on the physicochemical characteristics of an Entisol and water use efficiency of maize (Zea mays). Two types of biochar were produced with both coffee ground (CG) and coffee husk (CH) and their physicochemical properties were characterized. A greenhouse pot experiment, quantifying the growth of maize, with different rates of biochar amendments and fertilizing procedures was conducted in a completely randomized design. Treatments consisted in four replications of (i) control (native soil), (ii) synthetic fertilization and (iii) organic fertilization with cow manure, and (iv) the two types of biochar in four doses (4, 8, 12 and 16 Mg ha(-1)). Specific surface area (SSA) of CH was significantly higher than CG biochar but both types of biochar had higher SSA than soil. Nutrient and water retention properties of soil and maize growth were significantly improved with increasing biochar doses. The water use efficiency was 50% higher for the treatment with the highest dose of biochar. This is a significant found considering the potential of growing maize on a sandy soil in a dry regions of Brazil. Nutrient use efficiency as well as the C content in Entisol were largely improved by the use of biochar. Determination of SSA was a quick and robust method to anticipate the benefits of biochar on water retention of soil.