Effect of Bentonite and Biochar Application on Selected Physical Properties of Coarse-Textured Soil and Growth of Broccoli Plants

Abstract

Soils with rough texture have low fertility because they have low amounts of colloidal and organic matter resulting in low physical characteristics and the inability to retain water and nutrients. Thus, physically, organic amendments and soil conditioners are applied to enhance physical properties and their capacity to hold water and nutrients. The study was carried out in Babil Governorate, Iraq, at 32 o 47 W7.38 N, 44 o 25 W33.63 E, at 31 m above sea level, and during the 20252026 season, to examine the impact of the addition of bentonite and biochar on certain physical characteristics of coarse-textured soil and the development of broccoli plants. The experiment was carried out in the form of factorial experiment with the Randomized Complete Block Design (RCBD) with three replicas where each replica consisted of nine experimental units. In the research two factors were used. The first one was the addition of bentonite in the level of 0, 10 and 20 Mg ha^-1 represented as B0, B1, and B2 respectively. The second was the biochar addition at 0, 5, and 10 Mg ha^-1, which was referred to as C0, C1, and C2 respectively. It was demonstrated that treatment of addition of bentonite at 20 Mg ha^-1 reflected better in the mean bulk density, soil moisture content at field capacity, soil moisture content at wilting point and available water in the soil with percentage improvements of 4.19 , 26.86 ,12.11 and 41.71 respectively compared to the treatment without addition (control). The outcome of the addition of biochar also revealed that the treatment 10 Mg ha^-1 showed the superiority of the treatment in terms of total porosity, soil moisture content at field capacity, soil moisture content at wilting point, and availability of water in the soil, which increased by percentage of 4.09, 10.54, 6.55, and 14.10, respectively, with respect to the control treatment (not added biochar). The binary interaction revealed that the treatment (20 Mg ha^-1 bentonite + 10 Mg ha^-1 biochar) performed better in the mean soil moisture content at the field capacity, soil moisture content at the wilting point and the available water in the soil, where the percentage changes were 41.50, 24.02, and 58.87, respectively