Influence of organic and mineral fertilizers on nutrient leaching

Between 2002 and 2009 the influence of fertilizer type on drainage water formation and nutrient leaching was investigated in one crop rotation at the Bern- Liebefeld lysimeter station. Slightly higher crop yields were obtained with purely organic fertilizer than with pure mineral or organic-mineral fertilizers. One of the reasons for this may be that optimum manure management is possible in a lysimeter trial. However the three fertilizer methods differed only slightly in amounts of drainage water, drainage water nitrate concentrations and leached nutrient loads. These were much more strongly influenced by climatic conditions and the crop cultivated. A greater differentiation between the treatments could presumably have been achieved with a longer trial period because of the long-term after-effects of organic nitrogen. On the one hand these after-effects produce slight yield increases over the years, but on the other hand an increase in leaching losses can be expected owing to greater humus mineralization.