Sweet Potato Cultivation Optimization: From Substrate to Post-Harvest Storage

Substrate Preparation and Sweet Potato Variety Selection

The sweet potato (Ipomoea batatas) is a crop of high nutritional value and great adaptability, essential in global diets. Its ability to thrive in diverse climatic conditions, from temperate to subtropical climates, makes it a robust option for family gardens and larger-scale productions in regions like Argentina and Latin America. This tuber, rich in vitamins, minerals, and fiber, not only offers considerable yield but also contributes to food security and agricultural production diversification. Analyzing efficient cultivation techniques and recent innovations optimizes its development and maximizes its productive potential.

Substrate Preparation and Variety Selection

A properly prepared substrate forms the foundation for successful sweet potato cultivation. It requires a loamy or sandy texture, with excellent drainage and good organic matter content to promote tuber development. Sweet potatoes prefer soils with a slightly acidic to neutral pH, ideally between 5.5 and 7.0. Incorporating mature compost or worm castings improves soil structure, its moisture retention capacity, and the availability of essential nutrients.

The choice of variety is crucial, influenced by local climatic conditions and market preferences. Varieties with copper skin and orange flesh, such as ‘Beauregard’ or ‘Covington’, are widely cultivated for their yield and nutritional quality. However, other options with white, yellow, or even purple flesh exist, offering diversity in flavors and culinary applications. Current research focuses on developing varieties with greater resistance to pests and diseases, and better adaptation to water stress conditions, a significant advancement in the face of climate change. Plant genomics allows for the identification of markers for these traits, accelerating breeding programs.

Propagation Techniques and Crop Establishment

Propagation Techniques and Establishment

Sweet potato propagation is mainly done through “slips” or “cuttings,” which are young stems obtained from mature tubers or mother plants. To start slips, tubers can be placed in water or a warm, moist substrate. Once the slips reach about 15-20 cm in length and develop roots, they are separated and ready for transplanting. This methodology ensures the preservation of the mother plant’s genetic characteristics.

Establishment in the garden should occur after all risk of frost has passed and the soil temperature exceeds 18°C, generally in late spring or early summer in the Southern Hemisphere. Planting is done on raised mounds or ridges, with spacing of 30-45 cm between plants and 90-120 cm between rows. The mounds facilitate drainage, warm the soil, and provide optimal space for tuber thickening. New trends in urban agriculture explore propagation in controlled hydroponic systems, allowing for a faster and more uniform start of slips before transplanting to the field or containers.

Crop Management: Irrigation, Nutrition, and Phytosanitary Control

Agronomic Management: Irrigation, Nutrition, and Phytosanitary Control

Proper irrigation management is fundamental, especially during the initial growth stages and tuber formation. Sweet potatoes require consistent moisture but without waterlogging. Drip irrigation systems are highly recommended, as they optimize water use and minimize the proliferation of foliar fungal diseases. Current technology allows for the implementation of soil moisture sensors that monitor water needs, adjusting irrigation automatically and precisely, representing a significant advancement in water use efficiency.

Regarding nutrition, sweet potatoes demand potassium for tuber development and phosphorus for a good root system, although their nitrogen requirements are moderate. A prior soil analysis allows for specific fertilization adjustments. Applying balanced organic fertilizers or compost teas at key stages of the crop cycle promotes vigorous growth.

Phytosanitary control focuses on prevention. Crop rotation is an effective strategy to reduce the incidence of soil-borne pests and diseases. Mulching with organic materials such as straw or pruning debris suppresses weeds, conserves moisture, and moderates soil temperature. For pests like the sweet potato weevil (Cylas formicarius) or certain caterpillars, biological control methods are prioritized, using natural enemies or pheromone traps. Regenerative agriculture promotes biodiversity in the garden, creating a more resilient ecosystem less dependent on chemical interventions.

Harvest and Curing Strategies

Harvest and Curing Processes for Preservation

Sweet potato harvest generally occurs between 90 and 150 days after transplanting, depending on the variety and climatic conditions. A visual indicator of maturity is the yellowing of leaves and cessation of stem growth. It is crucial to harvest carefully to avoid damaging the tubers, as wounds can reduce their quality and storage capacity. Using pitchforks or blunt-tipped tools is recommended, lifting the soil around the plant to expose the tubers.

After harvest, “curing” is an indispensable step to extend the shelf life of sweet potatoes and improve their flavor. This process involves maintaining the tubers at a high temperature (approximately 29-32°C) and high humidity (85-90%) for 5 to 10 days. During curing, small wounds heal, the skin toughens, and starches convert to sugars, intensifying sweetness. After curing, sweet potatoes are stored in a cool, dark place with good ventilation, at a temperature of 13-16°C. Advances in storage systems precisely control these variables, ensuring greater post-harvest preservation and reducing losses.

The sweet potato, with its exceptional nutritional profile and adaptability, is positioned as a strategic crop for food sustainability. Implementing informed cultivation practices, from soil preparation to harvest and curing, is essential for optimizing its yield. The integration of innovations such as genetic improvement, smart irrigation, biological control, and regenerative agriculture techniques not only enhances productivity but also fosters more resilient and environmentally friendly agricultural systems. Growing sweet potatoes contributes to a healthy diet and supports the development of more diverse and sustainable gardens in Argentina and the entire region.