Einfluß organischer Düngungen auf bodenphysikalische Parameter

Influence of organic amendments on soil physical properties The effect of applying crop residues additionally to fertilzers or farmyard manure on soil structure was studied in Upper Bavaria. Crop residues were applied each year for 13 years before sampling. The Aquic Hapludalf, derived from loess underlain by Tertiary fine sand, was cropped with vegetables. Resistance to penetration, saturated hydraulic conductivity (k_f), pore size distribution, and aggregate stability (AS) were determined. The application of residues and/or manure increased the organic matter content of the top soil, resulting in increases in AS and k_f. However, both of these parameters were higher following residue application rather than that of manure. Only the application of residues improved the plant available water capacity by about 10 mm within 70 cm depth of soil profile. The other properties were not significantly affected, probably because they were also influenced by the weather and soil management practices. The values for these properties must therefore be considered as only momentary.