The long-term goal of this research is to develop tools that can be used by farmers to construct nutrient budgets for N, P and K in organic cash grain and vegetable production systems.
Researchers interviewed farmers to document their soil fertility management practices and sampled soil amendments and vegetable and grain crops at harvest for nutrient analysis, to assess the quantities of nutrients entering and leaving the farm. A series of databases were developed that can be used to support nutrient management decisions.
Results and practical applications:
A prototype nutrient budgeting tool was developed which would utilize these databases to construct multi-year budgets at the field and farm scale. This prototype tool currently exists in Excel spreadsheet format and is available in electronic form.
The sample budgets for the study sites suggest that the majority of organic vegetable production systems are adding significant surpluses of the major nutrients, as much as 180-200 kg P and N ha-1 yr-1 in excess.