Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 2011
Publication Date: April 26, 2012
Citation: Liebig, M.A., Tanaka, D.L., Kronberg, S.L., Scholljegerdes, E.J., Karn, J.F. 2012. Integrated crops and livestock in central North Dakota, USA: Agroecosystem management to buffer soil change. Renewable Agriculture and Food Systems. 27(2):115-124. Interpretive Summary: Integrated crop-livestock systems have been purported to have significant agronomic and environmental benefits compared to specialized, single-enterprise production systems. However, concerns exist regarding the effect of livestock in integrated systems to cause soil degradation, thereby compromising agroecosystem sustainability. A study was conducted to evaluate the effects of residue management, frequency of hoof traffic, season, and production system (integrated annual cropping vs. perennial grass) on soil quality indicators in the surface 3 inches of soil from 2001 through 2008 in central North Dakota. Imposed treatments had negligible effects on soil quality, implying producers should not be concerned with soil degradation in integrated annual cropping systems where winter grazing is used. The use of no-till management and modest fertilizer application rates, coupled with annual freeze/thaw and wet/dry cycles, likely conferred an inherent resistance to change in near-surface soil properties. Accordingly, caution should be exercised in applying these results to other regions or management systems.
Technical Abstract: Integrated crop-livestock systems have been purported to have numerous agronomic and environmental benefits, yet information documenting their long-term impact on the soil resource is lacking. This study sought to quantify the effects of an integrated crop-livestock system on near-surface soil properties in central North Dakota, USA. Soil bulk density, electrical conductivity, soil pH, extractable N and P, mineralizable N, soil organic carbon, and total nitrogen were measured 3, 6, and 9 years after treatment establishment to evaluate effects of residue management (Grazed, Hayed, Control), frequency of hoof traffic (High, Low, None), season (Fall, Spring), and production system (Integrated annual cropping, Perennial grass) on near-surface soil quality. Values for soil properties were incorporated into a soil quality index (SQI) using the Soil Management Assessment Framework to assess overall treatment effects on soil condition. Residue management and frequency of hoof traffic did not affect near-surface soil properties throughout the evaluation period. Aggregated SQI values did not differ between production systems 9 years after treatment establishment (Integrated annual cropping = 0.91, Perennial grass = 0.93; P=0.5729), implying a near identical capacity of each system to perform critical soil functions. Results from the study suggest agricultural producers can convert perennial grass pastures to winter-grazed annual cropping systems without adversely affecting near-surface soil quality. However, caution should be exercised in applying results to other regions or management systems. The consistent freeze/thaw and wet/dry cycles typical of the northern Great Plains, coupled with the use of no-till management, modest fertilizer application rates, and winter grazing likely played an important role in the outcome of the results.