The effects of biochar on the biomass yield of elephant grass (Pennisetum Purpureum Schumach) and properties of acidic soils

Abstract

Although biochar can be considered as a potential amendment to ameliorate degraded soils with many studies reported, little is known about its effects on acidic soils grown with elephant grass (Pennisetum Purpureum Schumach), a bioenergy crop. The current study aimed to (1) examine the effects of coffee husk-derived biochar on the grass’s yield and properties of acidic soil and (2) identify potential mechanisms in determining the yield. A greenhouse pot experiment was conducted to test five treatments (no biochar – T1, 2% biochar-T2, 4% biochar-T3, 2% cow manure-T4, and a mixture of 1% biochar plus 1% cow manure –T5) in four replicates. The pots were grown with elephant grass for three successive harvests. Soil after each harvest was taken to analyze for 14 parameters, which were used for SQI estimation. Biochar significantly increased the biomass yield by 61 (T2) and 82 % (T3), compared to T1. pH, cation exchange capacity, and the concentration of Mehlich-1 P and exchangeable bases (K, Na, and Ca) were significantly enhanced, while exchangeable acidity and the concentration of exchangeable H+, Al, and Fe were significantly decreased following biochar addition. The SQI was significantly better in the biochar-added soil than the non-biochar soil. The improved biomass yield could be involved in a few mechanisms, including liming effect, co-addition of nutrients with the added biochar, and nutrient use efficiency. In brief, biochar is a potential amendment in mitigating the constraints of acidic soils, leading to the enhanced biomass yield of elephant grass in the soils.