In terms of global production, potato (Solanum tuberosum L.) is the fourth most important food crop after corn, rice and wheat. This crop is grown throughout the world. Present world production is some 321 million tons fresh tubers from 19.5 million ha.
Asia and Europe are the world's major potato producing regions, accounting for more than 80% of world production. China is now the biggest potato producer, and almost a third of all potatoes are harvested in China and India. North America was the clear leader in productivity, at more than 40 tons per hectare. Asian consumption represents almost half of the world's potato supply, but its huge population means that yearly consumption per person was a modest 25 kg in 2005. The heartiest potato eaters are Europeans. In Latin America and Africa consumption per capita is lowest, but increasing.
The potato plays a strong role in developing countries with its ability to provide nutritious food for the poor and hungry. The demand for potato is growing as both a fresh and processed food. The decreasing availability of land for area expansion means that yields will have to be improved. Critical to achieving improved tuber yields will be access to an adequate water supply, including more efficient use of scarce water and costly fertilizer inputs.
Potato is grown in about 100 countries under temperate, subtropical and tropical conditions. The potato is basically a crop of temperate climates. Yields are affected significantly by temperature and optimum mean daily temperatures are 18 to 20°C. In general a night temperature of below 15°C is required for tuber initiation. Optimum soil temperature for normal tuber growth is 15 to 18°C. Tuber growth is sharply inhibited when below 10°C and above 30°C. Cool conditions at planting lead to slow emergence which may extend the growing period. Tuber yield decreases with reduced sunshine hours per day. Potato varieties can be grouped into early (90 to 120 days), medium (120 to 150 days) and late varieties (150 to 180 days). Improved varieties include Russet Burbank, Desiree, Yukon Gold and Nicola, among others.
Potato requires a well-drained, well-aerated, porous soil with pH of 5 to 6. Compacted soils affect root penetration, water and nutrient uptake and tuber enlargement. The crop is moderately sensitive to soil salinity with yield decrease at different levels of ECe. ECe is the electrical conductivity of a saturated soil paste extract. The plant spacing is 0.75 m to 0.90 m between rows and 0.15 m to 0.3 m between plants under irrigated conditions, while sowing depth is generally 5 to 10 cm. Cultivation during the growing period must avoid damage to roots and tubers, and in temperate climates ridges are earthed-up to avoid greening of tubers.
Adoption of drip irrigation and fertigation in potato has proved to be technically feasible and economically viable and beneficial in many ways both in developed and developing regions of the world. Drip irrigation in many diverse agro-ecological situations registered higher yields (40 to 72 tons/ha) apart from saving in water (30 to 40%), fertilizer (20 to 25%) and improving quality of tubers (grade and composition) in comparison to conventional furrow, overhead and centre pivot sprinkler irrigation methods.
Under Turkey and Indian conditions drip irrigated potato registered 50 and 42 tons tubers/ha with an Net Present Value (NPV) of 2085 USD/ha and 2692 USD/ha respectively and a payback period of one year.
For high yields, the seasonal crop water requirements for a 70 to 150-day crop were estimated to be 150 to 750 mm under a range of climatic conditions and varying (70–180 days) length of growing seasons with a daily evapotranspiration rate of 4 to 5 mm/day. Irrigation scheduling using tensiometers enabled an efficient use of water, fertilizer and energy inputs.
Potato is a heavy feeder of nutrients. Its root system is shallow and fibrous, hence fertigation is recommended for higher nutrient availability and use efficiency. The aim of the fertigation program is to cover the difference between crop demand and supply. The nutrient requirements of drip irrigated potato are relatively high. Other best management practices include earthing-up, protection of crop from pests and diseases, need based weed management, harvesting and post harvesting operations to minimize losses.