SP 5 - Evaluation of nutrient availability and optimization of nutrient use efficiency
During the last decades vast areas of the south Siberian and Kazakh steppes received only little or no fertilizer. This led to a pronounced depletion in soil nutrients, particularly in nitrogen, which is made available to plants by mineralization of soil organic matter. An adequate fertilizer management to sustain agriculture in Kazakh steppe requires a comprehensive knowledge on the nutrient (macro and micro nutrients) status and their availability in soils. Hence, the aim of SP 5 is to analyze the nutrient balance and processes of nutrient cycling in the soil-plant system, depending on the land use method, agrotechnical practices and climatic conditions. Besides large-scale approaches to assess the nutrient supply, 15N labeling will be employed to quantify processes of the nitrogen cycling in the soil-plant system.