Agriculture is an important industry that provides food for human consumption. The decrease of land available for agriculture coupled with the increase of human population has required that agricultural lands increase their output. This was achieved through the use of improved crop varieties, more productive livestock, better weed and pest control and the increased use of fertilizers, specifically nitrogen fertilizers which has linearly increased to 1. 2 Mt in the 1980s. However, farming also affects the environment.
Increases in phosphorus and nitrate contents of water lead to increased biological activity and large concentrations of nitrate in drinking water create health hazards. J. K. R. Gasser studied the nitrogen cycles in agriculture and reported the results in his article “Agricultural Productivity and the Nitrogen Cycle. ” Gasser (1982) explained that nitrogen is emitted from the soil or from animal effluents as ammonia, nitrous oxide or N2. Considerable amounts of nitrogen are also recycled directly as animal urine and feces. The preceding crops in agricultural lands also affect the amount of nitrogen released for the current crops.
However, Gasser (1982) explained that no arable system provides enough nitrogen for the maximum production of crops such that additional nitrogen must be added in the form of fertilizers. Gasser (1982) reported that there is no evidence supporting that the increased use of nitrogen fertilizer also increases the total amount of nitrogen in soil-plant system. He stated that little of the nitrogen in circulation “will appear directly in the atmosphere or groundwaters, most will leave the agricultural system after one or more changes or subsidiary cycles” (Gasser, 1982, 313).
Gasser (1982) concluded that the losses from the system must be at least as large as the known inputs. He persuaded to quantify the movement of nitrogen, the understanding of which would allow the losses from agricultural system to be minimized improving the utilization of nitrogen in farming and reducing its effects on the atmosphere and water.
Reference Gasser, J. K. R. (1982). Agricultural productivity and the nitrogen cycle. Philosophical Transactions of the Royal Society B (Biological Science) vol. 296, no. 1082, 303-314.