Positive effects of cover crop mixtures on soil hydro-physical properties are partially offset by grazing in short-term integrated croplivestock system

Authors: SINGH, NAVDEEP - South Dakota State University; KUMAR, SANDEEP - South Dakota State University; Jin, Virginia; Schneider, Sharon

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: The adoption of integrated crop-livestock (ICL) systems in the northern Great Plains gives agricultural producers the opportunity to diversify their farming enterprises while minimizing negative environmental impacts. Using cover crops and grazing are key parts of ICL systems. This study was conducted to investigate the influence of cover crops and grazing under a short-term ICL system on soil properties related to compaction and water availability. Cover crops alone tended to decrease soil compaction and increase soil water holding capacity in surface soils (to 8" depth). However grazing cover crops or cash crop residues tended to increase soil compaction, but not to the point where crop growth was limited. Cover crops and grazing did not increase soil organic matter within 3 years, indicating that these benefits will likely take many more years to show.

Technical Abstract: Cover crops and grazing play critical roles in the successful implementation of integrated crop-livestock systems (ICLSs) because they can have a direct impact on soil functions. The present study was conducted to assess the impacts of cover crops and grazing on soil physical and hydrological properties. Two sites (northern Brookings [Brookings-N] and northwestern Brookings [Brookings-NW]) were established in 2016 and 2017, respectively, in South Dakota USA. Specific objective was to evaluate the impact of cover crops (CCs) and grazed CCs under oat (Avena sativa L.)/CCs–corn (Zea mays L.) rotation on soil physical and hydrological properties. Study treatments included (i) legume-dominated CC (LdC), (ii) cattle-grazed LdC (LdC+G), (iii) grass-dominated CC (GdC), (iv) cattle-grazed GdC (GdC+G), and (v) no CC and no grazing (NC). After 2-3 years of management, cover crops and grazing did not impact soil organic carbon (SOC) and total nitrogen (TN) stocks, and their values at approximate depth of 0-20 cm ranged from 50.9 to 60.6 Mg C ha-1 and 3.65 to 4.92 Mg N ha-1, respectively, among the treatments at each site. Cover crops decreased soil bulk density ('b) at 0-10 and 10-20 cm depths and, in general, increased soil water retention (SWR), total porosity, and quasi-steady infiltration rate (Northern Brookings only) compared to the NC. Cattle grazing generally increased 'b but did not exceed the critical limits for root proliferation at either depth. Soil water retention, total porosity, and water infiltration rate decreased in response to grazing. In conclusion, cover cropping in shorter duration (2-3 yr study) enhanced some soil physical and hydrological properties, however, grazing cover crops and crop residue neutralized these effects.