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Climate Smart Agriculture (CSA) encompasses all practices that mitigate climate change and at the same time enhance farmers’ livelihoods and adaptation to changing climate. Nutrient management is an important tool for farmers to increase yields. Efficient use of nutrients is necessary to limit greenhouse gas (GHG) emissions and costs of external inputs. To enable an overall assessment of the opportunities that nutrient management presents for CSA, nutrient cycles and dynamics need to be thoroughly understood. This report describes a framework to parametrise the impacts of nutrient inputs on the nutrient balance, crop yield and soil fertility, both in the short and the long term. Separating short term versus long term processes and internal crop processes versus crop-soil interactions results in four sets of equations that are mutually consistent. These can be viewed as alternative approaches to quantify nutrient requirements and associated impacts, depending on purpose of a study. Set 1 expresses nutrient uptake requirement as a function of target yield, both in short and long term. Set 2 expresses input requirements as function of target uptake, soil nutrient supply and fertiliser recovery in the short term. Set 3 is similar in structure and purpose to Set 2, but includes a long term feedback of nutrient input on fertiliser recovery via soil fertility. Set 4 is a reduction of Set 3, under a specific boundary condition imposing ‘efficient management’in a simplified manner. The full sequence of relating a target yield to input requirement (or vice versa) is expressed by combinations of these sets: Sets 1 and 2 (short term), Sets 1 and 3 (long term equilibrium …