Joint International Conference on Long-term Experiments ...

APPLICATION OF A DIGESTATE AS A NUTRIENT SOURCE AND ITS
EFFECT ON SOME SELECTED CROPS AND SOIL PROPERTIES 1
ABSTRACT
Marianna Makádi 1 , Attila Tomócsik 1 , József Lengyel 2 ,
Zsolt Bogdányi 1 , Árpád Márton 1
1 Research Centre of CAS of University of Debrecen
H-4432 Nyíregyháza, Westsik Vilmos u. 4-6.
2 Bátortrade Ltd. H-4300 Nyírbátor, Árpád u. 156/A.
The largest biogas plant of Hungary is operated in the city of Nyírbátor, NE Hungary. A
substantial amount, some 95.000 m 3 of digestate is originating every year, as the
residual material of biogas production. A study was conducted on the utilization of this
material as a nutrient source for different crops. In this paper we present the results
obtained with winter wheat and triticale. The use of the digestate has a more
pronounced effect on triticale than on winter wheat. On the average, the yield of winter
wheat and triticale were increased by 20.8 % and 51.42 %, respectively, and the grain to
straw ratio was also increased by the treatments with the digestate. As for soil
properties, the treatments caused positive changes in the case of humus content, but they
increased the Na content of the soil.
Keywords: biogas, digestate, nutrient supply, winter wheat, triticale
INTRODUCTION
According to the regulations of Law No. XLIII./2000 on waste management, by 2014
the amount of biologically degradable waste types disposed in landfills should be
reduced to 35 % of the total amount of the waste landfilled in 1995. A significant
amount of organic waste can be composted and used as natural fertilizer and soil
improving material. The other possible treatment of organic wastes is their utilization in
biogas plants. The main products of this treatment are biogas (methane) and heat, while
by-product is digestate, which can also be utilized as source of nutrients in agriculture.
This anaerobic treatment is environmentally friendly because it utilises renewable
energy sources such as plants, and destroys and utilises organic wastes such as offal.
The fermentation residue – the digestate – can substitute for the artificial fertilizers
(Kovács, 2007).
Numerous papers deal with the importance of quality and quantity of basic
materials in biogas production. But very few papers are available on the utilization of
the digestate as a plant nutrient source. Qi et al. (2005) examined in North China the
effect of fermented waste as organic manure in cucumber and tomato production. They
have found increasing yield and vitamin C-content of about 18 %. Banik and Nandi
(2004) investigated biogas residual slurry manure on the yield, protein and mineralcontents
of oyster mushroom. They have found positive effects.
Besides the examination of the effect of the digestate on the crop yields of different
plants, it is also very important to study its effects on the soil properties.
1 This project is supported by the grant GVOP-3.1.1.-2004-05-0220/3.0.
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