Integrating Sheep Grazing into Cereal‐Based Crop Rotations: Spring Wheat Yields and Weed Communities

Abstract

Crop diversification and integration of livestock into cropping systems may improve the economic and environmental sustainability of agricultural systems. However, few studies have examined the integration of these practices in the semiarid areas of the Northern Great Plains (NGP). A 3-yr experiment was conducted near Bozeman, MT, to compare the effects of crop rotation diversity and weed management practices imposed during fallow periods [sheep (Ovis aries) grazing, reduced tillage, and conventional tillage] on spring wheat (Triticum aestivum L.) yields and weed pressure. Management treatments were applied to replicated whole plots, within which the split-plots received crop rotation treatments [continuous spring wheat (CSW) and a 3-yr rotation of annual forage, fallow, and spring wheat, where each phase was present in each year]. In the initial 2 yr, the realized rotational treatments were wheat-fallow and CSW. In the final year, wheat was grown following all phases of the diversified rotation. Yields were similar among management treatments within the wheat-fallow and CSW rotations. Weed pressure was generally low but perennial weeds were more abundant in grazing-managed, wheat-fallow systems. The integration of livestock into the annual hay crop-fallow-spring wheat rotation was associated with a nearly 30-fold increase in weed pressure and a yield reduction of 51.2% compared to conventional management. The results suggest that although targeted sheep grazing is a viable alternative to conventional fallow management in CSW and wheat-fallow rotations, successful integration of livestock in diversified cropping systems requires more effective weed management practices. ABStRACtCrop diversi cation and integration of livestock into cropping systems may improve the economic and environmental sustainability of agricultural systems. However, few studies have examined the integration of these practices in the semiarid areas of the Northern Great Plains (NGP). A 3-yr experiment was conducted near Bozeman, MT, to compare the e ects of crop rotation diversity and weed management practices imposed during fallow periods [sheep (Ovis aries) grazing, reduced tillage, and conventional tillage] on spring wheat (Triticum aestivum L.) yields and weed pressure. Management treatments were applied to replicated whole plots, within which the split-plots received crop rotation treatments [continuous spring wheat (CSW) and a 3-yr rotation of annual forage, fallow, and spring wheat, where each phase was present in each year]. In the initial 2 yr, the realized rotational treatments were wheat-fallow and CSW. In the nal year, wheat was grown following all phases of the diversi ed rotation. Yields were similar among management treatments within the wheat-fallow and CSW rotations. Weed pressure was generally low but perennial weeds were more abundant in grazing-managed, wheat-fallow systems. e integration of livestock into the annual hay crop-fallow-spring wheat rotation was associated with a nearly 30-fold increase in weed pres...

Effects of crop rotation and sheep grazing management on the seedbank and emerged weed flora under a no-tillage integrated crop-livestock system

“…Research is being conducted on a variety of cropping systems to develop more effective integrated weed management methods that are ultimately sustainable and reduce reliance on herbicides (Lechenet et al ., 2017). Investigations into the effects of including livestock grazing in crop-based systems have demonstrated that, compared with conventional cropping systems, ICLSs can result in lower of weed infestation as well as lower costs and risks associated with herbicide usage (Tracy and Davis, 2009; Miller et al ., 2015; Lehnhoff et al ., 2017). However, these investigations revealed that, in some years, livestock led to an increase in weed infestation in arable lands (Miller et al ., 2015).…”

Impacts of cropping system and management practices on the assembly of weed communities

“…The re‐integration of crop and livestock production offers the potential to improve the sustainability of farming systems by managing weed and insect pest populations, improving soil quality, increasing yield, augmenting pollinator populations and improving land use efficiency (Hilimire, ). While effects of mixed crop and livestock systems on farm productivity and profitability have been documented (Tracy & Davis, ; Miller et al ., ), the role that animal grazing could have as a filtering factor conditioning the assembly of weed communities is largely unknown. The goal of this study was to evaluate the impact of cropping system (a perennial [lucerne] vs. an annual (continuous spring wheat, CSW) and contrasting weed management practices in CSW (mechanical, chemical and sheep grazed) on weed abundance, diversity and community composition.…”

Green and animal manure use in organic field crop systems

“…(2019). Fewer weed problems occurred in crop rotations that included forages (Entz et al., 1995, 2002; Miller, Menalled, Sainju, Lenssen, & Hatfield, 2015). Field crop yield and overall system economics were improved by incorporating animal grazing into cropping schemes (Kumar et al., 2019).…”