Acacia nilotica Biochar Improves Sandy Soil Structure and Stimulates Root Development in Muscat Grape
Ghulam Murtaza1 
, Muhammad Usman2 , and Rashid Iqbal3*
Abstract. The effectiveness of biochar as a soil amendment is well recognized for improving soil fertility and plant root architecture. However, its beneficial effects on root development in perennial woody species require further investigation. In this 14-week greenhouse experiment, we evaluated the effects of Acacia nilotica-derived biochar on soil physical properties and Muscat grape growth. Muscat grape plants were grown in sandy soil amended with four biochar rates, 4%, 8%, 12%, and 16%, based on dry soil weight. Soil properties and root traits were then assessed. The results showed that adding 16% biochar to sandy soil reduced soil bulk density by 41%, increased total porosity by 51%, and improved water holding capacity by 1.11 times compared with sandy soil without biochar. Biochar incorporation also reduced soil acidity and improved soil buffering capacity, resulting in a more favorable soil pH several months after application. In addition, biochar stimulated fine root development, significantly increasing root length, root crossings, and root forks while reducing average root diameter. Overall, Acacia nilotica wood waste can be converted into valuable biochar for improving sandy soil quality and promoting grape root development. This approach supports waste recycling, improves soil physical conditions, enhances grape growth, and contributes to circular economy-based agriculture. Therefore, Acacia nilotica-derived biochar can be recommended as a promising soil amendment for Muscat grape cultivation, particularly in sandy soils where improved water retention and root growth are needed.
Keywords: Acacia bark-biochar, Muscat grape, Ultisol soil, root structure, soil amendment