Pea (Pisum sativum) is grown as a vegetable crop for both fresh and dried seed. Present world production is about 10.5 million tons dry pea and 7 million tons fresh pea.(FAOSTAT, 2001).
The varieties range from tall climbing to small bunch types with the latter having a shorter growing period. Pea is a cool climate crop and optimum mean daily temperature is 17°C with a minimum of 10°C and a maximum of 23°C. Germination is affected by soil temperature; at 5°germination takes 30 days or more, at l0°C about 14 days and at 20 to 30°C about 6 days. Young plants can tolerate light frost but flowers and green pods are injured by light frost. In the tropics near the equator, peas are grown at about 1500 m altitude, or as a winter crop in areas away from the equator. The normal growing period is 65 to 100 days for fresh pea with an additional 20 days for dry peas. The growing period is extended under cool conditions.
The crop does well on most soils with good drains e and pH of 5.5 to 6.5. Fertilizer requirements are about 20 to 40 kg/ha N, 40 to & kg/ha P and 80 to 160 kg/ha K. Pea is capable of fixing atmospheric nitrogen, which meets its requirements for high yields. However, a starter dose of 20 to 40 kg/ha N is beneficial for good early growth.
Pea is sensitive to soil salinity with yield decrease at different levels of ECe similar to that of bean, or 0% at ECe 1.0, 10% at 1.5, 25% at 2.3, 50% at 3.6, and 100% at ECe 6.5 mmhos/cm.
Plant spacing depends on variety and type and whether bunch or climbing, and is between 0.6 to 0.9 x 0.05 to 0.1 m with a wider spacing when grown along with stakes. Depth of sowing is 2 to 5 cm. Prevention against root rot requires good drainage and rotation. Common rotation crops are alfalfa, potatoes and sugarbeet.
The graph below depicts the crop stages of pea, and the table summarises the main crop coefficients used for water management.