Influence of biocompost and farmyard manure on soil properties and on growth of Acer pseudoplatanus

The influence of biocompost and farmyard manure on several soil properties and on growth of Acer pseudoplatanus (seedlings, two years old) was investigated for an alfisol derived from loess during two years. The following treatments were carried out: 758 dt/ha and 3000 dt/ha biocompost, 535 dt/ha farmyard manure, and no supply of organic material. With the farmyard manure and the lower compost application almost the same amounts of N and C-org were added to the soil. Shortly after incorporating the organic materials to the soil the fertilizing effect of already mineralized N has to be considered. The mineralization of N for all organic materials during both years was lower than expected from results in the literature. At the end of the second year there was no difference in the N-min-content between the untreated plots and the treatments with farmyard manure and the lower amount of compost. The amount of N-min in 0-90 cm in autumn was about 20 kg/ha, for the higher amount of compost about 40 kg/ha. The P- and K-content of the soil increased for all treatments with organic material. The amounts of N, P, and K added to the soil with the organic materials was higher than the uptake by trees. CAC and pH increased after addition of the organic materials. The percentage of K and Na at the CAC increased, Ca decreased. The amount of organic matter in the soil was only increased with the higher amount of compost. Pore volume and the amount of wide pores increased only shortly after incorporation of the organic materials. At the end of the second year there was still an increase in pore volume only with the higher amount of compost, which, however, was now due to an increase in middle-sized pores. The amount of middle-sized pores increased also with the lower amount of compost and with farmyard manure, wide pores, however, decreased to a higher degree. As a result pore volume decreased. Trees for the farmyard manure treatment had a lower N-content, those for both compost treatments had higher N-content, P- and K-contents were always higher compared to the untreated plot. Growth of plants for both compost treatments was slightly increased compared to the untreated plot, growth of trees for the farmyard manure treatment was decreased compared to all other treatments.