Soils of Northern Great Plains are relatively young (11000 to 14000 years old) and have some of the highest organic matter levels (4 to 7%) of all mineral soils in the United States (Overstreet and DeJong-Huges, 2009). However, continuous cropping, poor management practices and loss of topsoil have adversely affected the soil organic matter levels. Continue reading
If manure increases formation of larger (macro) and more stable soil aggregates, several benefits may result for fields fertilized by manure compared to commercial fertilizer including:
- Reduced runoff and soil erosion;
- Increased water infiltration into the soil possibly leading to greater drought tolerance; and
- Partial offsetting of higher soil P levels resulting from manure application and limiting P loss to local surface water.
Farmers and ranchers are becoming increasingly aware of the importance of soil quality/health to the productivity and sustainability of their agricultural system. Research and field observations have demonstrated that carefully managed manure applications can contribute to improved soil quality with limited environmental and social risks. However, a comprehensive assemblage of outputs and conclusions from research studies, field trials, soil labs databases, and other sources has never been developed. Continue reading
Tunsisa Hurisso and Steve Culman, School of Environment and Natural Resources, Ohio State University
In short, the answer is usually both.
Soil organic matter is a mixture consisting of various compounds (e.g. simple sugars, cellulose, proteins, etc.) derived primarily from plants and microbes. It represents 1-6% by mass of agricultural soils, but plays a disproportionate role in soil function. Organic matter in soils acts like a sponge, holding nutrients (sequestration or stabilization) that become available to plants when organic matter is broken down (mineralization) by the collective action of the soil food web (mainly by bacteria and fungi). In addition to nutrients, organic matter also enhances the soil’s water holding capacity, making farmlands more resilient to periods of drought. In contrast, when organic matter is depleted due to repeated plowing and/or removal of crop residues from the field, the ability of a soil to hold water and nutrients will be greatly diminished. Therefore, growers should strive for both organic matter stabilization and mineralization processes to ensure short-term crop productivity and to build long-term soil resilience.