The use of sorbents on the basis of humic acids to reduce ammonia levels in stable environment

Veterinarni Medicina 44, 1999, 331-338

Laboratory testing of sorption properties of humic substances, which were exposed to increased ammonia levels from 0 to 300 mg/g in a system, showed a highly significant (P less than or equal to 0.01) increase of ammonia levels up to the value of 27.1 +/- 1.32 mg/g of ground humic substances. The increase of ammonia level in the system to 400 and 500 mg/g had not any significant effect on its concentration in the humic substances (27.8 +/- 208 and 28.7 +/- 1.73 mg/g). The results of laboratory testing of ammonia binding to humic substances are shown in Fig. 1, In a series of experiments performed in experimental stables of the institute and aimed at testing the use of humic acids for the reduction of free ammonia level, 3% of sodium humate were administered in the ration for pigs in two subsequent periods (I and II). At the same time, nitrogen balance (the amount of nitrogen intake by feed and excretion by faeces and urine) was monitored. In another two periods (III and IV) 1 kg of ground humic substances was applied twice a day on the floor of experimental stable, i.e. 150 g/m(2)/day. Eight pigs were included in the experiment, housed in balance cages, four in one cage in two identical separated stables. The pigs received feed mixture composed of 68.3% of wheat, 20.0% of barley, 10.0% of soya extracted meal and a mineral supplement. The average daily intake of feed mixture was 1.16, 1.27, 2.00 and 2.20 kg/animal/day in periods I, II, III and IV, respectively. The levels of free ammonia were recorded daily at 7 a.m. and 2.30 p.m. in both stables throughout the whole experimental period. Air temperature and relative humidity were measured in the stables as well as outdoor temperature and atmospheric pressure (Tab. I). Significantly lower (P less than or equal to 0.05) average levels of free ammonia (6.9 +/- 1.58 ppm) were found in period I in the stable

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