Section 144(1) in The U.P. Zamindari Abolition and Land Reforms Act, 1950
(1)Whenever any land held by a bhumidhar which is not used for the purposes connected with agriculture, horticulture or animal husbandry which includes pisciculture and poultry farming, has become land used for such purposes, the [Assistant Collector-in-charge of the sub-division may suo motu or on an application, after making such enquiry as may be prescribed] [Substituted by U.R Act No. 37 of 1958.], make a declaration to that effect and thereupon the bhumidhar shall, as respects the land, be subject to the provisions of this chapter.