Bihar lies in the river plains of the basin of the river Ganga. It is endowed with fertile alluvial soil with abundant water resources, especially ground water resources. This makes the agriculture of Bihar rich and diverse.
The average rainfall in Bihar is 1053 mm. The rainfall in Bihar is largely due to the south-west monsoon, which accounts for around 85% of total rainfall in the state. The other sources (winter rain, hot-weather rain, and the north-west monsoon) account for the remaining 15%.
The net sown (to sow seed, as for the production of a crop) area in Bihar is 60% of its geographical area. This percentage is much higher than the all-India average of 42%.
Rice is cultivated in all districts of Bihar. Autumn rice, aghani rice, and summer rice are three different varieties of rice grown at three different times of the year. The average production of rice is around 5 million tonnes each year.
Some five decades back, wheat cultivation was very restricted in Bihar. After green revolution success, wheat was planted by Bihari farmers on a larger scale, and wheat now occupies the status of major crop of the rabi (spring) season. The average annual wheat production is approximately 4-4.5 million tonnes.
Maize is also cultivated, with an average annual production level of approximately 1.5 million tonnes and a steady positive trend in production. The leading producer districts are Khagaria and Saharsa.
Pulses such as moong, arhar, peas, and khesari are grown, more in southern than in northern Bihar. The leading districts are Patna, Bhojpur, Aurangabad, and Nalanda.
The total area under vegetable cultivation is currently about 11% of the state’s gross sown area, and is increasing. The important vegetable crops include potato, onion,tomato, cauliflower, and brinjal. Hajipur in Vaishali is famous for an early variety of cauliflower that reaches market in the last week of September.