The activities conducted under AfSIS objective 4 were geared towards the development of site-specific management recommendations.
The purpose and objectives under these are outlined elsewhere in more detail (e.g., in Diagnostic Trials: A field Guide: Huising et al, 2011) and include:
- To determine the major nutrients and soil factors limiting crop production.
- To predict crop response to nutrient application in terms of crop growth, yield and nutrient uptake, from soil and foliar spectral and other AfSIS covariates (e.g. land degradation indices) under variable soil fertility conditions.
- To understand the reasons for and scope of non-responsive soils to (a) decide whether it is required to rehabilitate non-responsive soils, and (b) develop management practices required to restore productivity.
- To establish and maintain a database of diagnostic trials data that will allow analyses and synthesis of results from diagnostic trials across sites; that will increase data density over time allowing for improving reliability of assessments and inferences.
The purpose of this document is to present, or bring to the attention of the reader, the methods and tools developed within AfSIS Objective 4 from field trial/experiment design and implementation to data analysis and interpretation.