International Journal of Horticulture, 2025, Vol.15, No.1, 41-50 http://hortherbpublisher.com/index.php/ijh 44 4 Cultivation Practices for Yield Optimization 4.1 Soil preparation and planting techniques Proper soil preparation is essential for ensuring optimal root development and high yields. Fresh-eating sweet potatoes grow best in well-drained sandy loam soils with a pH between 5.5 and 6.5 (Motsa et al., 2015). Fields should be cleared of weeds and large debris, and plowing should be done to a depth of 25~30 cm to facilitate root expansion (Harvey et al., 2022). Raised ridges or mounds are recommended to improve drainage and prevent waterlogging, especially in areas with high rainfall. Planting should be timed with the onset of the rainy season to ensure adequate soil moisture for sprouting (Low et al., 2020). Vine cuttings of 20~30 cm, with at least three nodes, should be used for planting. A spacing of 30 cm between plants and 75~90 cm between rows allows sufficient space for root enlargement and minimizes competition (Cheboi et al., 2024). 4.2 Irrigation and water management Efficient water management is critical, especially during the establishment and tuber initiation stages. Sweet potatoes require consistent soil moisture early in the growing season but prefer drier conditions as harvest approaches to prevent tuber cracking and rot (Zhapar et al., 2023). Drip or furrow irrigation is recommended to optimize water use and reduce water stress, especially in regions with limited rainfall. Overwatering should be avoided, as it can lead to poor aeration and root rot. In areas where rain is unpredictable, supplemental irrigation ensures steady crop growth and enhances tuber quality (Laurie et al., 2017). 4.3 Fertilizer application and nutrient management Balanced nutrient management is crucial for achieving high yields and quality tubers. Sweet potatoes require nitrogen for early vine growth, phosphorus for root development, and potassium to enhance tuber formation and disease resistance (Low et al., 2020). Organic matter such as compost or manure can improve soil structure and nutrient availability. A typical fertilization schedule includes a basal application of phosphorus and potassium at planting, followed by nitrogen top-dressing three to four weeks later (Martins et al., 2023). Excess nitrogen should be avoided in later stages, as it promotes vine growth at the expense of tuber development (Cheboi et al., 2024). Boron is also essential to prevent cracking and internal necrosis of tubers. Regular soil testing ensures that nutrient deficiencies are identified and corrected promptly for optimal crop performance (Islam et al., 2022). 5 Disease and Pest Management 5.1 Common diseases and pests affecting fresh-eating sweet potatoes Fresh-eating sweet potatoes are affected by several pests and diseases that impact yield and tuber quality. Among the most damaging pests are sweet potato weevils (Cylas formicarius), which attack both vines and tubers, leading to significant crop losses, particularly in dry seasons when soil cracking allows easier pest access. Other threats include whiteflies and aphids, which transmit viral diseases like sweet potato feathery mottle virus (SPFMV) (Longdom, 2021a; Wikifarmer, 2023). Fungal diseases such as black rot and leaf spot also reduce productivity, especially in warm, humid climates (Wikifarmer, 2023). Proper pest and disease management is critical for maintaining high yields and ensuring marketable tubers. 5.2 Integrated pest management (IPM) strategies and best practices Integrated pest management (IPM) strategies are essential for sustainable control of sweet potato pests and diseases. IPM approaches combine crop rotation with non-host plants, biological control using parasitoid wasps, and mechanical methods like pheromone traps for monitoring weevil populations. Applying organic fungicides and neem-based insecticides provides an eco-friendly alternative to chemical controls, reducing environmental harm (Longdom, 2021b). Early planting and timely weeding are essential practices to avoid pest build-up, and reflective mulches can deter whiteflies and aphids. Additionally, scouting and monitoring help detect infestations early, enabling targeted control before outbreaks occur (Wikifarmer, 2023). 5.3 Development and use of resistant varieties in subtropical regions The use of resistant sweet potato varieties is crucial for managing diseases and pests effectively. In subtropical regions, orange-fleshed sweet potato (OFSP) varieties with enhanced resistance to pests like weevils and viral
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