Soil C Impacts of Organic Amendments: Practical Models for Farmer Decision Support

Managing soil carbon (C) is an important part of agriculture’s role in both mitigating and adapting to climate change, whilst feeding a growing global population. Adding organic materials to the soil surface can be a valuable practice for C storage. However, regular on-farm measurement to monitor soil C is often impractical due to costs and spatial heterogeneity of soil C stocks. Soil C models can be utilised instead, but their data requirements must be reasonable to provide a useful alternative to farmers.

Ideally, decision support tools should provide the most information from the fewest data points. Sub-field scale equilibrium and saturation dynamics of the soil C pool introduce complexity. The result is that environmental, management and time factors must be represented within modelling approaches.

This analysis will compare the utility of several model approaches (including IPCC Tier 1) for predicting the impact of organic amendments in realistic farmer data scenarios. The impact of equilibrium concepts will be considered through factors such as time, baseline soil C values, as well as climate, environment and soil type. How should these factors be prioritised to focus farmer data requirements when providing decision support? What is the information cost of reducing the data burden?