Nitrogen mineralization from mature bio-waste compost in vineyard soils II. Test of N-mineralization parameters in a long-term in situ incubation experiment.
A field incubation experiment was carried out to test the applicability of N-mineralization parameters for mature bio-waste compost for use in a simulation model. The parameters were previously obtained from a laboratory experiment. Micro-lysimeters were used for incubation, containing four different vineyard soils that were treated with three different compost-application rates (0, 30, and 50 Mg compost ha-1). Between 2.0% and 45.2% of total bio-waste compost N was mineralized and leached from the micro-lysimeters during the two-year investigation period. The application of a simulation model for soil N dynamics revealed two major drawbacks of the model: (1) in most of the soils, extraordinary high mineralization rates were observed within a few weeks after compost amendment, which could not be explained by the model, and (2) the average compost-N-mineralization rates were estimated as being close to the observed rates (-6%), but distinct deviations in some cases (-46% to +29%) led to considerable miscalculations in long-term simulations. Excluding the effect of these two processes from the data set, the remaining variance could be well explained by the model for all soils treated with compost (modeling efficiency 0.98). Based on the average performance, the mineralization parameters for mature bio-waste compost are considered to be applicable for use in any simulation model based on the double-exponential approach for calculating fertilizer recommendations, whereas the functions calculating the impact of environmental factors on N mineralization in the model need to be revised. The initial mineralization flush observed in most of the compost treatments was attributed to a priming effect. The experiment showed that such a priming effect can cause exceptionally high rates of N mineralization from mature bio-waste compost in a viticultural environment, which exceed the potential mineralization rates known for bio-waste compost applied to arable soils in Germany.
Nendel, C.; Reuter, St.; Kersebaum, K.C.; Kubiak, R.; Nieder, R. 2005. Nitrogen mineralization from mature bio-waste compost in vineyard soils II. Test of N-mineralization parameters in a long-term in situ incubation experiment. Journal of Plant Nutrition and Soil Science 168 (2), 219-227.