Organic matter added to tilled fields improves soil health.

In this graph, we compare the median scores of 152 tilled fields, with organic matter inputs (brown bars) and without organic matter inputs (blue bars).   This graph shows that tilled fields with added organic matter inputs have higher median scores for soil organic matter (SOM), soil respiration, organic carbon, microbially active carbon, soil health, microbial biomass and fungi-bacterial ratios than tilled fields without organic matter inputs. Our data shows the same to be true for untilled fields, but to a lesser extent.
Organic matter inputs, including composts, manures, and mulches can jump-start the formation of soil organic matter, add microbiology to the soil, and supply macro and micro nutrients. However, continuous inputs can also contribute to soil health challenges, such as excessive phosphorus levels. In our project, “organic matter inputs” only include inputs from “outside” the study field, and don’t include manure deposited by animals grazing in that field or bio-mass generated by crops and cover crops.  It seems that extra organic matter inputs have a larger effect on tilled fields than on pastures.