The effect of different quality composts and meat meal on maize, mustard and triticale yield was examined in the Őrbottyán Experiment Site of HAS CAR on Danube-Tisza mid-region calcareous sandy soil. The heterogeneous soil contained 0-8% CaCO3 and 1.0–1.5% humus. The thickness of the humus layer was 60-80 cm, the pH(H2O) was between 6.8–7.5 and pH(KCl) was 6.3–7.3. The quantity of the clay fraction was 10-15%. The production site was moderately supplied with available phosphorus and weakly supplied with nitrogen and potassium.

The experiments were established in 2002 and 2003 individually with 5 treatments and 4 replications, that is with 20-20 plots. The size of each plot was 5×8=40 m2 with randomised block design. The treatments were 0, 25, 50, 100, 200 t ha-1 fresh compost or 0, 2,5, 5, 10, 20 t ha-1 meat meal at the time of the establishment of the experiments. Therefore, a one-time load was imposed in 2002. In the subsequent years, the after-effects of composts and meat meal were observed. In 2002, maize was sown in monoculture as an experimental crop, while it was mustard in 2003 and triticale from 2004 on.

According to our examinations, slaughterhouse waste could be considered a relatively concentrated organic matter if their N, P, Ca, Zn and Cu stocks are several times higher that those of farmyard manure. There was drought in the first two years of the experiment (2002 and 2003) and no fertiliser effect was observed in maize and mustard after the application of the ripe compost. However, larger doses of unripe compost caused blocked development and 20-50% perishing of the maize population, as well as 30-60% loss of the above-ground green mass.

In the adequately rainy year of 2004, the third year after-effect of the 200 t ha-1 dose of the ripe and unripe compost resulted in 1.6 and 9 t ha-1 above-ground yield surplus, respectively. The second year after-effect of the semi-ripe compost and the bony meat meal resulted in the biomass of triticale increasing 1.5 – 2 times. In the subsequent years these after-effects became more moderate. The effect of ripe compost and bony meat meal could be tracked on this soil for three years, that of the semi-ripe compost could be tracked for 5-6 years and the unripe compost had its effect for 7-8 years. The examined slaughterhouse waste products are considered to be concentrated, slow-acting organic manure.

The highest amount of compost (200 t ha-1) and bony meat meal (20 t ha-1) resulted in the incoroporation of 20-120 t ha-1 dry matter, 12-48 t ha-1 organic matter and 0.6-6.8 t ha-1 fat. The highest peak of mineral elements was 13.5 t ha-1 Ca (33.7 t ha-1 CaCO3) and 11.6 t ha-1 P (26.6 t ha P2O5). The K, Mg, Na and S intake amounted to several hundred kg ha-1 in the case of the composts. Zn showed a maximum load of 42 kg ha-1 and other elements’ maximum loads were the following: Mn 21, Sr 18, Ba 12, Cu 8, Cr 2. In the unripe compost the toxic NH4-N form reached 275 kg ha-1, while it reached 113 kg ha-1 in the semi-ripe compost. At the same time, the incorporation of ripe compost with ploughing represented a maximum of 193 kg ha-1 NO3-N.

To sum it up, we can arrive at the conclusion that the widespread use of sterilised, ripe slaughterhouse composts could be recommended in the field. Based on their composition and efficiency, they can especially increase the fertility of acidic sandy soils.

Keywords: Composted slaughterhouse waste, long-term field experiment, yield, calcareous sandy soil