The aim of this experiment was to study the effect of types and rates of biochar on growth, yield, and yield component of garden pea at Bule wereda, Southern Ethiopia. The treatments consist of two types of biochar (corncobs and Lantana camara) and four rates of biochar (0, 6, 12, and 18 t ha−1). The experiment was laid out as a randomized complete block design in a factorial arrangement with three replications. Soil samples were collected at a depth of 0–30 cm and germination parameter and phonology of garden pea were recorded. The result showed that soil bulk density, porosity, pH, and exchangeable acidity were significantly (P<0.001) affected by biochar application. The result also showed that maximum germination percentage of garden pea seeds (95.23%) was recorded at 18 t ha−1 of Lantana biochar. The shoot length was significantly (P<0.05) affected at 15 days and 30 days of biochar application. Moreover, fresh shoot weight and dry root biomass, number of seeds per pod, and grain yield of garden pea were significantly affected (P<0.05). Of the substrate and application rate applied, Lantana camara 12 t ha−1 and Lantana camara 18 t ha−1 significantly increased yield of garden pea. Thus, further studies on effect of different biochars and their specific role are suggested to increase crop production.

The aim of this research was to investigate the effect of biochar amendment on soil acidity and other physico‐chemical properties of soil in Southern Ethiopia using a field experiment of three treatments: (1) biochar made of corn cobs, (2) biochar made of chopped Lantana camara stem, and (3) biochar made of Eucalyptus globulus feedstock and a control, in which neither of the biochar was used. Each treatment had three levels of 6, 12 and 18 t ha−1. The experiment was setup with RCBD in a factorial arrangement with three replications. In this regard, a total of 36 plots (each 2 × 2 m size) were applied with three replications to the depth of 0–15cm. From these 36 plots, composite soil samples were collected to the depth of 0–30 cm and analyzed for bulk density, total porosity, pH, soil organic carbon, total nitrogen, available phosphorus, potassium, and exchangeable acidity using standard procedures before and after biochar application. Two‐way ANOVA was also used to analyze the impact of the biochars on soil acidity and other properties. For the treatments that had significant effects, a mean separation was made using Least Significance Difference (LSD) test. The results showed the application of biochar significantly reduced, soil bulk density and exchangeable acidity when compared with a control (p < 0.05). Moreover, the total soil porosity, soil pH, total nitrogen, soil organic carbon, available phosphorus, and potassium were significantly increased in the soil. From among applied biochar treatments, Lantana camara applied at the level of 18 t ha−1 had a higher impact in changing soil physico‐chemical properties. In general, the study suggests that the soil acidity can be reduced by applying biochar as it can amend other soil physico‐chemical properties.