By James Hoorman, Hoorman Soil Health Services
As fertilizer costs increase, farmers want to either lower their fertilizer costs or find ways to conserve soil nutrients. Cover crops can help do both things. Legumes and clovers sequester nitrogen (N) and grasses and radishes make phosphorus (P) more available. Most conventional soil tests measure inorganic soil nutrients but are less reliable accounting for organic or carbon-based plant nutrients. As soil health improves, nutrient availability and nutrient efficiency generally improves due to higher soil microbial activity.
Manure improves soil health and soil organic matter (SOM). Solid chicken manure is high in N, P, and calcium. Liquid manures (hog and dairy) can be major sources of nutrients but have a high-water content (dairy, 98% water; hog, 95% water) and with high transportation costs, can be more expensive. Composting solid manure tends to concentrate available nutrients because as manure decomposes, the volume generally reduces to about a third of the original volume.