- Agronomic: barley, soybeans, wheat, grass (misc. perennial), hay
- Additional Plants: native plants
- Animal Production: feed/forage
- Crop Production: conservation tillage
- Education and Training: extension, technical assistance
- Natural Resources/Environment: biodiversity
- Pest Management: allelopathy, chemical control, cultural control, mulches - killed, physical control
- Production Systems: agroecosystems
- Soil Management: earthworms, organic matter, soil analysis, nutrient mineralization, soil quality/health
- Sustainable Communities: sustainability measures
Quality of a silty clay soil after 22 years in plow, chisel and no-till was compared to grass. Plowing degraded soil at a faster rate than chisel, while no-till enhanced quality. Plowing reduced total N of grass by 5300 lb/ac, while N was only reduced 2600 lb/ac with no-till. Plow lowered organic C in grass soil by 11,000 lb/ac, while no-till sequestered 10,600 lb/ac. Carbon dioxide evolution from soil was 0.70 g/cm3 for plow, and carbon dioxide evolution from grass with chisel or no-till was at 0.50 g/cm3. Soil pH, EC, Ca, Na, Fe, and Cu were higher in plow than chisel or no-till. No-till enhanced soil physical and biological properties that eliminated Fe and Zn deficiency in grain legumes present on plow. Erodible soil aggregates (< 2 mm) were highest on plow and chisel that, combined with low surface residue cover, subjected these systems to wind erosion potential.
Soil quality has gained attention in recent years due to environmental issues related to soil degradation. Soil quality has also gained the attention of producers interested in the sustainability of their soils or farming systems. The term soil quality is often open to interpretation, but has been defined as the capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health (Doran & Parkin, 1994). A discussion of the links between soil quality and the health of plants, animals, and humans is provided by Cihacek et al. (1996). The quality or health of a soil can be determined by monitoring, over time, specific chemical, physical, or biological properties. Once the properties are measured, the producer can infer quality values and make changes in management if the quality is deteriorating.
Janzen, et al. (1992) suggested that soil quality must be expressed in terms of productivity. Productivity is determined by land management, which can influence the chemical, physical, and biological properties of the soil. The climate, topography, and hydrology at any specific location also modify quality of the soil. Deibert (1997) summarizes these intrinsic and extrinsic factors in relation to conservation tillage. Carbon sequestration by soils has gained attention with the adoption of the international Kyoto Protocol on reduction of greenhouse gas as summarized by Bruce, et al. (1999) and McConkey, et al. (1999). Soils can serve as sinks to remove carbon dioxide from the air and a better understanding of these processes or relationships is needed. A meeting at Ohio State University presented an overview of current knowledge and research gaps (Lal, et al., 1996). Participants at the meeting indicated that additional information is needed in 10 specific areas, including the magnitude of inorganic carbon in arid regions, carbon sequestration with soil depth under different management practices, the interaction of N, P, and S with carbon sequestration, and the relationships of soil quality or soil structure to enhance the capacity of the soil to serve as a carbon sink. An international symposium on agricultural practices and policies for carbon sequestration in soil was recently held at Ohio State University (1999). Cihacek and Ulmer (1995) presented some preliminary work on soil organic carbon losses in a long-term crop-fallow system on the Great Plains. They indicated that carbon loss from tillage incorporated crop residue was a greater contributor to atmospheric C losses than was due to prior cultivation when prorated over 80 years. Little information was available on the relationship of carbon and other long-term residue management-crop rotations found in the Northern Plains. Recently Follet and McConkey (2000) made some estimates of the amount of carbon that can be sequestered in the Great Plains by using good agricultural practices. Halvorson, et al. (2000), discussed the effect of nitrogen fertilization on carbon sequestration.
The objectives of this study were: (1) to measure selected chemical, physical, and biological properties on a grassland area and on three long-term 22-year residue management systems in a small grain-row crop rotation to determine the impact on soil quality; (2) to determine carbon sequestration in the soil profile under the different systems; and (3) to measure the evolution of carbon dioxide from the soil with the different systems under different N fertilizer variables over two different crop seasons.
Changes in soil quality over short periods of time are usually quite subtle; thus, longer periods are needed to evaluate measurable changes in soil properties due to various management practices. The research site used in this study is one of a few locations in the northern Great Plains of the United States where management practices have continued for more than 20 years, offering the opportunity to measure changes in soil quality on a cultivated site compared to an adjacent grassland area. The chemical, physical, and biological properties measured in this study will provide some baseline information on the impact of long-term residue management and crop rotation practices on soil quality in the northern Great Plains. This information can also be used to develop best management practices to maintain the sustainability of soils, one of our most precious resources. This information can be used as a guide for selecting soil properties that producers can use to best evaluate the quality of their soil in relation to productivity. Results will also provide additional data for the Soil Quality Institute within the Natural Resource Conservation Service (NRCS), which is currently focusing on soil quality guidelines as part of their conservation effort. The soil carbon and carbon dioxide respiration information under different management practices will fill the void in data needed (outlined at recent meetings on carbon sequestration at Ohio State University in 1996 and 1999) to understand the relationships and develop models for determining the soil as a sink for carbon sequestration under arid and semi-arid climatic conditions present in the Northern Plains.