Introduction: Potatoes are a versatile crop that are grown worldwide and form an essential part of the human diet. They are a staple food that can be consumed in various forms such as mashed potatoes, French fries, potato chips, or baked potatoes. Potato farming can be a profitable venture if the right agronomic practices are followed. This article will discuss the agronomic requirements for potato farming.
Soil requirements: Satisfactory yields of potatoes can be achieved on a wide range of soil types. Potatoes are also suited to acid soils, pH 5.5 to 6.9 is ideal. Heavy clay soils are suitable provided they are well-drained and ploughed early. Light or shallow soils are prone to drought, and yields of maincrop potatoes will be lower if a shortage of water occurs during the growing season. Soils with high organic matter such as peat or muck, if adequately drained, can also produce high-quality potatoes, particularly for the fresh market. However, there is a need for a well sound protection program because cutworms and white grubs tend to be a problem in soils with high organic matter. In Zimbabwe, most satisfactory yields have been attained from red clays due to the high cation exchange capacity which enables them to retain moisture and nutrients. Sandy soils or sandy loam soils which contain little clay or little organic matter, when properly irrigated and fertilized, will produce high yields of tubers with excellent culinary and processing quality. Potatoes are more tolerant to low pH than most other crops.
Rotation: A correct rotation is required to avoid the build-up of potato cyst eelworm, disease, and volunteers. Potatoes should not be grown more often than one year in four, but in areas of intensive potato production, a longer interval may be required. Potato cyst nematode (eelworm) may persist in soil for 20-30 years. Volunteer potatoes, in addition to contributing to the eelworm problem, are also a source of blight and virus disease and should be controlled where possible in succeeding crops.
Land Preparation: A good head-start at optimum even plant population is essential in the quest for good yields of quality potatoes. The profitability of potatoes is directly related to germination/emergency percentage per hectare and this is strongly influenced by seedbed preparation. The idea will be to have over 90% emergency percentage to ensure a good plant population per hectare. Good land preparation should aim to achieve the above objective. Where the grass is ploughed up it is recommended that the grass is burned off in advance of ploughing using Glyphosate. Deep cultivation (down to approximately 30-45 cm) is an essential start to seedbed preparation. Subsequent cultivations aim to provide a fine seedbed with 12 – 15 cm of clod-free tilth. Loose cloddy seedbeds will dry out, causing slow growth; irregular emergence, and low stem counts. Wait until soils are dry enough, and then use an appropriate implement for cultivation. Cultivating soils that are not dry often results in compaction, and damage to soil structure. This restricts the rooting capacity and subsequent yield of the potato plant. These days chisel ploughing to a depth of 30-45cm is mostly practiced. Chisel ploughing has advantages over disc ploughing: uses 25-50% fuel less depending on soil texture compared to disc ploughing, no burying of trash hence promoting soil cover with subsequent organic layer build-up which in turn protects soil from erosion agents, promotes the existence of beneficial aerobic microbial organisms which might be killed through burying them along with trash in the case of using a disc plough, does not promote the development of a soil pan which will restrict drainage and good root development.
Fertilization: Potatoes require a large amount of nutrients, and they are particularly responsive to potassium and nitrogen. Other essential nutrients for potato growth include phosphorus, calcium, magnesium, sulfur, boron, copper, iron, manganese, molybdenum, and zinc. A soil test is essential to determine the nutrient status of the soil and to calculate the quantity of fertilizer required. It is important to maintain the balance of nutrients in the soil by applying fertilizers at the appropriate times, rates, and forms. Nitrogen is the most important nutrient for potato production, and it is needed in large amounts throughout the growing season. However, excessive nitrogen can delay maturity and increase the risk of disease. Therefore, it is important to apply nitrogen at the right time and in the right form. Generally, the first application should be made at planting, and subsequent applications should be made during the growing season at intervals of 3-4 weeks. Potassium is also important for potato growth, and it is needed in large amounts throughout the growing season. Potassium is important for tuber initiation and development, as well as for disease resistance. Therefore, it is important to apply potassium at the right time and in the right form. Generally, potassium is applied at planting, but it can also be applied during the growing season. Phosphorus is important for early growth and root development, and it is usually applied at planting. Calcium is important for tuber quality, and it can be applied as a foliar spray during the growing season. Micronutrients are also important for potato growth, and they can be applied as a foliar spray during the growing season. The most important micronutrients for potatoes are boron, copper, iron, manganese, molybdenum, and zinc.
Irrigation: Potatoes require a regular supply of water throughout the growing season, and the amount of water required will depend on the soil type, climatic conditions, and stage of growth. Generally, potatoes require about 500-700 mm of water per growing season. Irrigation is essential during tuber initiation and development to ensure a good yield and quality. Excess moisture can cause diseases and reduce yields, so it is important to manage irrigation carefully. The frequency and amount of irrigation will depend on the soil type and the weather conditions, but it is generally better to apply smaller amounts of water more frequently to avoid waterlogging the soil.
Conclusion: Potatoes are an important food crop worldwide, and their cultivation requires careful attention to soil requirements, rotation, land preparation, varietal selection, fertilization, and irrigation. Soil requirements must be carefully managed to ensure that the potatoes have access to the nutrients they need to grow and produce high-quality tubers. A correct rotation is necessary to avoid the build-up of potato cyst eelworm, disease, and volunteers. Good land preparation is essential to achieve a good plant population per hectare. Varietal selection is critical to ensure a high yield and quality of tubers. Fertilization must be carefully managed to ensure that the potatoes have access to the nutrients they need to grow and produce high-quality tubers. Irrigation is essential during tuber initiation and development to ensure a good yield and quality.
