Study of the Potential Use of a Bentonite Clay-sulfur Composite in the Organic Agriculture

Abstract

  Organic production is growing annually both worldwide and in Georgia, driven by its critical importance for a healthy environment and sustainable future. However, to achieve the desired outcomes in organic agriculture, it is essential to replace synthetic pesticides and agrochemicals with bio-preparations and inputs permitted in organic farming. The present study addresses one of such environmentally safe alternative developed at the Georgian Institute of Organic Chemistry: a bentonite clay-sulfur composite. The effect of an aqueous suspension of this composite on various vegetable crops and grapevines was evaluated between 2022 and 2025 at the Tsilkani and Jighaura experimental bases of the LEPL, Scientific-Research Center of Agriculture. The experiments were conducted in three replications, using experimental, standard and control variants.

   The study demonstrated that the use of a standard sulfur preparation (Sulfolak) reduced the incidence of powdery mildew on pumpkin by an average of 49.5% compared to the control. A similar result was achieved using a 2% suspension of the bentonite clay-sulfur composite, while combining it with a 6% suspension of Makvaneti kaolin increased the efficacy to 57.4% relative to the control. The bentonite clay-sulfur composite suppressed powdery mildew even more effectively on grapevines; disease prevalence on the leaves and berries in the experimental variants did not exceed 5–7%, whereas it reached 75–80% in the untreated control variant.

    Additionally, the population of tomato russet mites was reduced by an average of 60% using both the experimental bio-preparation and Sulfolac individually, while 6% kaolin suspension enhanced this reduction to 75%.

    Regarding crop yield, the reduction of pests and diseases through the application of the bentonite clay-sulfur suspension led to a 51.2% increase in tomato yield and a 96.9% increase in pumpkin yield compared to the control. Composition of kaolin further improved these yields to 67.6% and 124.7%, respectively.