Demonstrating Short-Term Impacts of Grazing and Cover Crops on Soil Health and Economic Benefits in an Integrated Crop-Livestock System in South Dakota

Colin Tobin,Tong Wang,Sandeep Kumar,Peter Sexton,Shikha Singh

doi:10.4236/ojss.2020.103006

Abstract

Integrated crop-livestock system (ICLS) is an alternative that can help in intensifying food production while benefiting the environment. However, the assessments of the impacts of ICLS on the soil and economic benefits relative to specific environments in South Dakota are still lacking. This study was to assess the effects of ICLS on soil health and economic benefits under a corn (Zea mays L.)-soybean (Glycine max L.)-rye (Secale cereale L.) rotation in South Dakota. Cover crops blends were planted after the rye crop, and grazing treatments (with and without) were applied after the cover crops establishment in 2015-2016. Data from this study indicate that most soil properties are not negatively impacted by grazing. However, the grazing increased soil bulk density (BD) and decreased soil organic carbon (SOC) and soil water retention (SWR) compared with the ungrazing. The effect of grazing on corn yield was not significant. The cover crops did not impact the pH, electrical conductivity (EC), total nitrogen (TN), β-glucosidase, acid hydrolysis carbon fraction, microbial biomass carbon, and SWR, but impacted the SOC, hot/cold water carbon fraction, BD, infiltration rate (qs) in some phases and depths. The effects of different cover crop blends on corn yield were not as strong. The economic analysis showed that implementing ICLS increased the profit of the farm by $17.23 ac−1 in the first year and $43.61 ac−1 in the second year. These findings indicate that ICLS practices with proper management benefit soil health and producer income.

Highlights

Crop and livestock production dominate in South Dakota [1], with the eastern portion of the state in crop production while the western portion is mainly rangeland, pastureland and cattle production
We explored more options during various parts of the growing season and the impacts of grazing and cover crops on soil properties, corn yield, and economic benefits
Results from this study showed that when we applied proper grazing management techniques (40% - 60% biomass removal), soil properties were not negatively impacted by grazing except for soil organic carbon (SOC), bulk density (BD), and soil water retention

Summary

Introduction

Crop and livestock production dominate in South Dakota [1], with the eastern portion of the state in crop production while the western portion is mainly rangeland, pastureland and cattle production. There has been a conversion of pasture and rangelands into croplands due to increased commodity prices [2] This acreage reduction has increased pressure on native rangeland and pasturelands, resulting in more stress on vegetation and soil health. In the center and western portion of the state, small grains are a large portion of the acres planted. This area has a typical crop rotation of corn-wheat (Triticum aestivum L.)-sorghum (Sorghum bicolor L.)/sunflowers (Helianthus annuus L.). The no-till (NT) practice is the most commonly used soil moisture conserving management technique that is used in much of South Dakota. It can help the producers reduce soil moisture losses by leaving the residue to act as a buffer between the sun’s rays and the soil surface [5]

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