Effect of biochar and biodigester effluent in Lao PDR

Effect of biochar and biodigester effluent on yield of Taro (Colocasia esculenta) foliage

Bounmay Bouaravong, Nguyen Nhut Xuan Dung¹ and T R Preston²

Plant Science Department, Faculty of Agriculture and Environment, Savannaket University, Savannnaket province, Lao PDR
bbounmay@yahoo.com
¹ Cantho University, Vietnam
² Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria (CIPAV), Carrera 25 No 6-62 Cali, Colombia

Abstract

Two experiments were carried out to evaluate effects ef soil amendment with biochar and biodigester effluent on biomass yield of Taro.  In the first experimemt, five levels of biochar (0, 0.5, 1, 1.5, 2 kg/m²) were applied to Taro grown in 3*3m plots according to a completely randomized (CRD) design with 4 replicates. All plots were fertilized with biodigester effluent at the rate of 50 kg  N/ha. There were linear increases in yield of Taro leaves and petioles, and in their content of crude protein, when biochar was applied to the soil at levels from 0 to 2 kg/m². Soil fertility as measured by pH, water-holding capacity and nitrogen content was increased linearly according to the level of biochar.
In the second experiment, five levels of biodigester effluent  (0, 25, 50, 75, and 100 kg N/ha) were applied to to Taro grown in 1*1m plots that had been amended with 2 kg/m² of biochar. Applying biodigester effluent at levels up to 100 kg N/ha resulted in linear increases in biomass yield and in crude protein content of leaves and petioles and to increased soil fertility as measured by pH, water-holding capacity and nitrogen content.