Microbial biocontrol and drought stress management using orange peels on spinach (<i>Spinacia oleraceae</i>) in Sokoto, semi-arid environment

A screenhouse experiment was conducted to determine the effectiveness of orange peels powder on spinach growth and productivity grown under soil water-deficit spinach condition in Sokoto, Sudan savannah zone of Nigeria. The orange peel was applied at a rate of 50 g to 5 kg of soil per pot. Growth and yield parameters such as plant height, number of leaves, leaf length, leaf area, and fresh weight and microbial population of the soil were determined using standard methods. The experiment was laid out in a randomized complete block design (RCBD) with four irrigation intervals 2, 4, 6 and to 8 days replicated three times and data were subjected to analysis of variance (ANOVA) significant differences among means were separated at 5% level of significance. Results showed that soil amendment with 50g of orange peels per 5 kg of soil and irrigation intervals at 4 days increased spinach yield and suppressed bacterial population higher than the fungal population in the soil. These findings suggest that the frequency of irrigation had a major effect on spinach yield and production cost, controlling watering intervals increase the spinach yield and reduce the production cost. Further research is needed to investigate the influence of orange peels on microbial diversity, optimal dosage of orange peel, and method of application for enhancing spinach yield.