The importance of water resources for agricultural output and adequate food supply cannot be over-emphasized in a nation. Globally, about 70% of all water withdrawal from the hydrological cycle goes into agricultural production. Naturally, water from rain or snow is made available to crop either as surface water in humid climates or as underground water under sub-humid and arid conditions. In Nigeria, the climatic conditions reveal seasonal wet and dry regimes which separate between the semi-arid north, humid south, as well as the coastal zones where rain falls almost throughout the year. Four main river systems namely: the Niger-Benue, the Chad basin area, the Southwestern littoral and the Southeastern littoral, with trans-border flows from Cameroon are prominent parts of the water resource endowment of the country.
Although the average annual rainfall over the whole country is estimated at 1, 150 mm, Nigeria cannot depend on rain-fed agriculture in order to feed its teeming population; a supplementary supply of water in the form of irrigation is needed. Agricultural production can be enhanced through the development of irrigation infrastructure. While the industrious attempt of smallholder farmers are commendable, more can be achieved in food production through the provision of affordable irrigation facilities. Broadly, methods of irrigation can be classified as surface and overhead irrigation, each having its variants. In the surface category, we have flood irrigation water (from rivers, lakes, wells, boreholes, or public irrigation schemes) made to flow on the field through furrows or bay/ border Strip techniques. The major drawback of these techniques is the inefficient use of water most of which either evaporates or ends up being absorbed by the soil rather than the plants. The overhead category however, provides for more efficient use of water; although more expensive, its variants- the center-pivot, the traveling gun sprinkler and the drip system can help to sprinkle water on crops with more precision.
In Nigeria, the public irrigation schemes (government-executed), the farmer-owned irrigation scheme, and the flood plains called Fadama irrigation scheme the three categories of irrigation schemes available . More agricultural land (183,000 ha) is under private irrigation schemes than that under public schemes (35,840 ha). This is especially true, judging from the predominance of hand watering or gravity flow distribution among smallholder farmers in the country. Some use basin irrigation in which case water is stored in small encircled by earth banks built on the plots while those who practice of pressurized irrigation (i.e., drip and spray irrigation) are few. Harnessing water resources, particularly through tube well facilities, and sprinklers require the use of equipment that are not affordable to smallholder farmers. Furrow and basin irrigation may also be difficult to adopt by these farmers due to the high cost of labour to construct the water channel .
Although the Federal government of Nigeria established the River Basins Development Authorities (RBDAs) to ensure efficient utilization of nature’s endowment of water resources in Nigeria in 1986, lack of coherent irrigation subsector development policy and strategy; insufficient attention to management systems; inadequate funding still constitute problems to efficient use of water resources in the country. Other constraints to irrigation include high capital and operating costs; inadequate farm support services; wrong attitudes and awareness towards irrigation systems of crop production; poor operation, repair and maintenance; a low level of project ownership acceptance by the direct beneficiaries; and uncertain financial and economic viability [4, 6]. It could be implied from the forgoing that, focusing on adequate policy and management attention on irrigation farming can help in fully utilizing available water resources in Nigeria to enhance crop production.
 FAO. Nigeria: Geography, population and water resources. Accessed 26/04/2019. http://www.fao.org/3/V8260B/V8260B1b.htm
 The World Bank https://www.worldbank.org/en/topic/water-in-agriculture
 Irrigated agriculture to feed Nigeria. Accessed 26/04/2019. https://www.blueprint.ng/irrigated-agriculture-to-feed-nigeria/
 Irrigation farming in Nigeria.https://www.legit.ng/1100106-irrigation-farming-nigeria.html
 Irrigation, farm estates will boost agricultural production. https://punchng.com/irrigation-farm-estates-will-boost-agricultural-production/
 Bashir Adelodun and Kyung-Sook Choi (2018) A review of the evaluation of irrigation practice in Nigeria: Past, present and future prospects. African Journal of Agricultural Research. Vol. 13(40), pp. 2087-2097, 4 October, 2018 DOI: 10.5897/AJAR2018.13403.
 Helping smallholder farmers become expert tomato growers to serve local markets. Accessed27/04/2019 http://www.tomatojos.net/irrigation-practices-in-west-africa/2014/8/13/b4safd6js4fn2xzes6sssieuwjsz8l