The effect of corn rachis biochar (Zea mays L.) on the chemical properties of two soils from Honduras

Abstract

Soil is an essential resource for agriculture, as it provides the physical, chemical, and biological medium required for plant development. However, soil acidity limits the productivity of many tropical soils due to low nutrient availability and aluminum toxicity. Biochar has emerged as a sustainable alternative to mitigate soil acidity and improve soil fertility. The objective of this study was to evaluate the effect of corn rachis biochar on selected chemical properties of two acidic soils from Honduras under laboratory conditions. A completely randomized design (CRD) was used with three replications and three biochar rates (0, 20, and 40 t ha⁻¹), applied to soils collected from El Progreso and La Ceiba, both classified as very strongly acidic, with initial pH values of 4.74 and 4.57, respectively. The experimental units consisted of 3 L pots containing 800 g of soil incubated at moisture levels close to field capacity. The biochar was produced from corn rachis through slow pyrolysis at 500–700 °C for 3 h and 30 min. The results showed that the response to biochar depended on soil type and evaluation time. In soil from El Progreso, biochar increased the pH, particularly at the 2% rate after 2 months and at the 1% and 2% rates after 4 months. Electrical conductivity also increased after 2 months with the 1% and 2% rates, whereas no effects were observed on exchangeable Al or cation exchange capacity. In soil from La Ceiba, pH did not change after 2 months but increased significantly after 4 months, with the greatest effect observed at the 2% rate (p < 0.0001). In this soil, electrical conductivity also increased with the 2% biochar rate in both evaluation periods, and exchangeable Al decreased with the 1% and 2% rates, while cation exchange capacity showed no significant changes. Overall, after 4 months, pH increased by 1.10% in soil from El Progreso and by 6.12% in soil from La Ceiba.