I want to measure how sustainable the methods of nutrient budgeting (N,P, K) are, But, I don't have any clue how to start with this. Is there any model or something like that?
Sustainability can be measured by assessing performance of Social, Environmental, Nutritional, and Economic principles. While a balanced treatment of all three is an ideal goal, it is not always achievable. To have maximum level of sustainability these factors should be focused.