Effects of aquaculture wastewater application on growth, yield and water use efficiency of sweet pepper (Capsicum annum) and okra (Abelmoschus esculentus) intercrop

Abstract

Crop intercropping is important for improved land use efficiency by promoting complementary use of light, water, nutrients, and growing space between the component crops, while aquaculture wastewater contribute to improved crop yield. Therefore, the purpose of this study is to investigate their integrative impacts on the soil, growth, yield and nutritive quality of Okra and Pepper under different water managements. Irrigation water from aquaculture constructed wetland (CW), untreated/treated wastewater and groundwater sources were applied at two levels (100% and 60% of full irrigation - FI) to okra and sweet pepper under three cropping patterns (okra alone, sweet pepper alone, and okra/sweet pepper intercrop). The soil hydro-physical and chemical properties were determined using standard procedures. The growth parameter; plant height, number of leaves, leaf area, leaf area index and stem girth were measured weekly, while the fruits yield was determined at harvest. Results from the study showed that the treatment plots irrigated with untreated aquaculture water had the highest soil water content and nutrient at harvest in the okra/sweet pepper intercrop, thus resulting in higher growth, yield and nutritive quality of okra and sweet pepper. Moreover, the aquaculture waste water improved the water use efficiency of the pepper and okra crop under both sole planting and intercropping. Among the treatments, the okra fruit yield ranged between 1,440 and 35,906 kg ha -1 , while it ranges between 2,126 and 24,940 kg ha -1 for the sweet pepper. The field water use efficiency ranged between 3.83 and 57.3 kg ha -1 mm -1 for the okra crop, while it ranged between 2.37 and 11.29 kg ha -1 mm -1 . The main effects of cropping pattern and irrigation water source, as well as their interaction effects, were significant (P < 0.05) for most soil nutrient parameters. The Land Equivalent Ratio (LER) was mostly greater than 1 (LER > 1), thus emphasizing the suitability of intercropping okra with sweet pepper under aquaculture water application.