BIOTICALLY AND ABIOTICALLY INDUCED AMMONI A EMISSIONS FROM STABLE MANURE .2. INFLUENCE OF THE AMOUNT OF LINER AND THE STORAGE DENSITY

Experiments conducted over a period of 14 days with stable manure cons isting of wheat straw and slurry showed decreasing ammonia emissions ( 23.2 % > 18.3 % > 5.1 % of the N-total) with closer slurry:straw ratio s (1:0.05 > 1:0.01 > 1:0.03, corresponding to 2.5 kg < 5 kg < 15 kg st raw/LAU/day) as a result of a decline not only in the biotic (17.1 % > 12.8 % > 3.5 % of the N-total) but also in the abiotic emissions (6.1 % > 5.5 % > 1.6 % of the N-total), whereas an increase in storage den sity (0 kp/m(2) < 400 kp/m(2) < 800 kp/m(2)) reduced the biotic emissi ons (9.6 % > 2.8 % > 2.3 % of the N-total) but had no significant effe ct on the abiotic emissions (1.8 % less than or equal to 1.7 % > 1.8 % of the N-total). In case of wide slurry:straw ratios, almost exclusiv ely abiotically induced emission was detected at the start of the deco mposition process; then, by day 14, the contribution of this source to the total amount of ammonia emission had declined to 26.5% (1:0.05) o r 29.9% (1:0.1). That shows that the availability of carbon sources in low-straw stable manure at the start of the decomposition is a limiti ng factor for the microbial reincorporation of NH4+.