Response of Cauliflower (Brassica oleracae var botrytis L.) to Soil Application with Olive Mill Wastewater, Vinasse and Potassium Humate and its Reflection on Growth, Curds Yield, Dry Seed Yield and Enzyme Activity

Abstract

A field experiment was achieved over two consecutive winter seasons of 2018/2019 and 2019/2020 at Qaha Research Farm, Qaliobia Governorate, Horticulture Research Institute, Agriculture Research Center (ARC), Egypt. The study aimed to assess the positive impacts of using of Olive Mill Wastewater (OMW), vinasse and potassium humate at varying application rates (0, 50 and 100%) of each as soil application on plant growth, curds yield parameters, dry seed yield and its components, quality and seeds chemical composition of cauliflower Amshiry cv. The physical and chemical characteristics of the soil were evaluated, including enzymatic activity in the soil rhizosphere, specifically oxidoreductase enzymes such as catalase and peroxidase. The experiment was arranged in a randomized complete block design (RCBD) with seven treatments and three replicates. The obtained results demonstrated that applying 50% 0f vinasse followed by 50% of potassium humate led to enhanced plant growth, increased total curd yield, improved dry seed yield and its components, and positively impacted the physical and chemical properties of the investigated soil. The addition of 50% vinasse or 50% K- humate yielded the most favorable outcomes compared to other treatments or the control and at the same time save and reduce mineral fertilizer recommendation of cauliflower by 50 %. The most successful treatment, involving 50% vinasse application, resulted in a 34.7% and 31.6% increase in total curd yield (ton/ fed.) and a 28.7% and 30.6% increase in dry seed yield (kg/fed) over the control for the two experimental seasons, respectively.