Ammonia volatilization from arable land after application of cattle slurry. 1. Field estimates.

Abstract

Cattle slurry was surface-applied to bare soil in two experiments in September-November 1987, while in April-May 1988 two experiments were carried out in which the slurry was mixed with the upper 6 cm of the soil with a cultivator immediately after spreading. The 1987 experiments both lasted 18 days, the 1988 experiments 9 days. A micrometeorological technique, which did not disturb the dynamics of the air flow, was used to measure NH₃ volatilization. Volatilization losses were also determined indirectly from mineral-N contents of soil-slurry samples collected at intervals after application. Diurnal fluctuations in the NH₃ flux occurred throughout the experimental period, with maxima around midday and minima at midnight. The magnitude of the daily flux values decreased with time. The amounts of N lost through volatilization from surface-applied cattle slurry were 18 and 33% of the total N, resp., during the first 9 days, corresponding to 32 and 67% of the ammoniacal N applied with the slurry. Volatilization was negligible after day 9. Incorporation of the slurry into the soil considerably decreased the loss of N through volatilization: volatile losses of N after 9 days amounted to 6 and 7% of the total N, which corresponds to 11 and 16% of the ammoniacal N applied with the slurry. (Abstract retrieved from CAB Abstracts by CABI’s permission)