The agricultural sector has a limited amount of land to cultivate, the marginal product of an additional farmer is assumed to be zero as the law of diminishing marginal returns has run its course due to the fixed input, land. As a result, the agricultural sector has a quantity of farm workers that are not contributing to agricultural output since their marginal productivities are zero. This group of farmers that is not producing any output is termed surplus labour since this cohort could be moved to another sector with no effect on agricultural output. (The term surplus labour here is not being used in a Marxist context and only refers to the unproductive workers in the agricultural sector.) Therefore, due to the wage differential between the capitalist and subsistence sector, workers will tend to transition from the agricultural to the manufacturing sector over time to reap the reward of higher wages.