Enhancing sweetness: The impact of biofertilisers on purple sweet potato cultivation in mineral soil

Purple sweet potatoes (Ipomoea batatas) have captured the attention of nutritionists and food enthusiasts alike for their rich anthocyanin content, contributing to their vibrant hue and potential health benefits. However, purple sweet potato is not as popular as the orange and white varieties because of the high anthocyanin content, which may cause the purple sweet potato to taste less sweet than the other varieties. The purple sweet potato, known as Lembayung, has a high anthocyanin content (3.19-7.05 mg/100g) and tastes less sweet than other commercial varieties. Enhancing its’ sweetness will make it even more acceptable to the consumer while being a healthy starch substitute. Biofertilizer is a low cost and renewable source of plant nutrients that supplements chemical fertiliser. They have a symbiosis relationship with plant roots, where they break down nutrients in the soil for easy absorption and change of sugar from plant roots. This study was carried out to determine the effects of biofertiliser with chemical fertiliser application on quality (sweetness) and yield of Lembayung planted in mineral soil. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. The treatment involving combination of biofertiliser with chemical fertiliser and application of processed chicken dung as a basal fertiliser resulted in the highest sweetness with total sugar and SSC (Soluble solid content) of sweet potatoes. Studies conducted in MARDI reveal that biofertiliser application on the 2nd and 4th week after planting combined with chemical fertiliser application on the 3rd, 5th and 8th week after planting can improve the sweetness and yield of Lembayung sweet potatoes planted in mineral soil. This was demonstrated by increased total sugar in Lembayung tubers by up to 123.8% compared to sweet potato plants fertilised only with chemical fertilisers.