Wouldn’t it be great if we could accurately predict the change in soil quality based on our past, present, and future farming practices? Farmers could then understand the effects their management changes would have on their soil health. Yeah, that would be nice…but it doesn’t exist.
NRCS’s Soil Conditioning Index (SCI) does however, provide farmers with soil health trend analysis. Recently, NRCS’s Mike Kucera (National Soil Quality & Ecosystems Branch) told me that he believes the SCI is still the best available predictive tool for soil health.
SCI is generated by running the RUSLE2 model which is used by growers for conservation planning. The inputs to RUSLE2 are used to predict the balance of soil organic matter, effects of tillage/field operations and estimated soil erosion; summing them together for an overall soil condition rating. These components are weighted, with organic matter at 40%, field operations at 40%, and soil erosion at 20%. SCI scores can be negative (indicating a decline in soil condition), zero (maintaining soil condition), or positive (improving soil condition). By observing the SCI score, one can identify where a major soil health problem may be found and focus on management changes that will most readily influence the lagging component.
The Soil Conditioning Index can help a farmer understand how soil health is affected by the following practices:
- Raising crops that produce high amounts of residue that are retained on the field
- Utilizing cover crops to increase organic matter
- Utilizing manure or crop mulch to add organic matter to the soil
- Limiting the number of tillage operations
- Minimizing the amount of wind and water erosion on a field
- Using production techniques that increase residue production