Nitrogen cycling in high-input versus reduced-input arable farming.

Abstract

A comparison was made between a high-input and two reduced-input farming systems using a rotation of winter wheat-sugarbeet-spring barley-potatoes on a calcareous silt loam soil. Nitrogen balance sheets for the growing seasons of 1986-1988 showed N deficits of 0-170 kg/ha, suggesting substantial N losses to the environment. The uncertainty about actual N losses mainly depended on the uncertainty of estimated net N mineralization. Periods with much rainfall in 1987 and 1988, inappropriate use of animal manure and soil compaction may partly account for the heavy N losses in all three farming systems. Potential rates of N-cycling processes were studied over the years to observe effects of changes in management. To increase the efficiency of mineral and organic N inputs, and to decrease N losses, soil inorganic-N concentrations should be kept low, especially during periods when losses are likely to occur. (Abstract retrieved from CAB Abstracts by CABI’s permission)