Multi‐Species Cover Crop Mixtures in the Northern Great Plains

Compacted soils affect global crop productivity and environmental quality. A field study was conducted from 2014 to 2020 in the northern Great Plains, USA, to evaluate the effect of various rooting systems on soil compaction in 2 yr rotations of camelina (Camelina sativa L.), carinata (Brassica carinata A.) and a cover crop mix planted in place of fallow with durum (Triticum durum D.). The study was designed as a randomized complete block with three replications in a no-tillage system. The soil was classified as Dooley sandy loam (fine-loamy, mixed, superactive, frigid Typic Argiustolls) derived from glacial till parent material. Three measurements of soil penetration resistance (PR) were taken with a penetrometer to a depth of 0–30 cm within each plot. Soil moisture contents were determined using a TDR sensor at the time of PR measurements. Both measurements were monitored prior to planting in spring and after harvest. Initial PR results from spring 2014 showed that all plots had an average of 2.244 MPa between the 8–20 cm depth, due to a history of tillage and wheel traffic caused by various field activities. Covariance analysis indicated that soil PR was not significantly affected by crop type and moisture content. After one cycle of the 2 yr rotation, the 2016 measurements indicated that the compacted layer existed at the same initial depths. However, after two and three cycles, soil PR values were reduced to 1.480, 1.812, 1.775, 1.645 MPa in spring 2018 and 1.568, 1.581, 1.476, 1.458 MPa in 2020 under camelina, carinata, cover crop mix, and durum treatments, respectively. These findings indicate that previous cover crop roots could effectively improve soil compaction by penetrating the compacted layer, decompose over time and form voids and root channels. Although these results are novel and significant, further research is needed on different soils and under cover crops with different root systems to support our findings prior to making any conclusion.

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Responses of leached nitrogen concentrations and soil health to winter rye cover crop under no‐till corn‐soybean rotation in the Northern Great Plains

Journal of Environmental Quality ◽

10.1002/jeq2.20294 ◽

2021 ◽

Author(s):

Arun Bawa ◽

Rachel MacDowell ◽

Sangeeta Bansal ◽

John McMaine ◽

Peter Sexton ◽

...

Keyword(s):

Great Plains ◽

Cover Crop ◽

Soil Health ◽

Northern Great Plains ◽

Winter Rye ◽

No Till ◽

Nitrogen Concentrations

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Introducing cover crops as fallow replacement in the Northern Great Plains: II. Impact on following wheat crops

Renewable Agriculture and Food Systems ◽

10.1017/s1742170521000508 ◽

2021 ◽

pp. 1-10

Author(s):

Maryse Bourgault ◽

Samuel A. Wyffels ◽

Julia M. Dafoe ◽

Peggy F. Lamb ◽

Darrin L. Boss

Keyword(s):

Winter Wheat ◽

Soil Water ◽

Great Plains ◽

Spring Wheat ◽

Cover Crops ◽

Cover Crop ◽

Northern Great Plains ◽

Wheat Crop ◽

Wheat Grain ◽

Grain Yields

Abstract The introduction of cover crops as fallow replacement in the traditional cereal-based cropping system of the Northern Great Plains has the potential to decrease soil erosion, increase water infiltration, reduce weed pressure and improve soil health. However, there are concerns this might come at the cost of reduced production in the subsequent wheat crop due to soil water use by the cover crops. To determine this risk, a phased 2-year rotation of 15 different cover crop mixtures and winter wheat/spring wheat was established at the Northern Agricultural Research Center near Havre, MT from 2012 to 2020, or four rotation cycles. Controls included fallow–wheat and barley–wheat sequences. Cover crops and barley were terminated early July by haying, grazing or herbicide application. Yields were significantly decreased in wheat following cover crops in 3 out of 8 years, up to maximum of 1.4 t ha−1 (or 60%) for winter wheat following cool-season cover crop mixtures. However, cover crops also unexpectedly increased following wheat yields in 2018, possibly due in part to residual fertilizer. Within cool-, mid- and warm-season cover crop groups, individual mixtures did not show significant differences impact on following grain yields. Similarly, cover crop termination methods had no impact on spring or winter wheat grain yields in any of the 8 years considered. Wheat grain protein concentration was not affected by cover crop mixtures or termination treatments but was decreased in winter wheat following barley. Differences in soil water content across cover crop groups were only evident at the beginning of the third cycle in one field, but important reductions were observed below 15 cm in the last rotation cycle. In-season rainfall explained 43 and 13% of the variability in winter and spring wheat yields, respectively, compared to 2 and 1% for the previous year cover crop biomass. Further economic analyses are required to determine if the integration of livestock is necessary to mitigate the risks associated with the introduction of cover crops in replacement of fallow in the Northern Great Plains.

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Organic zero-till in the northern US Great Plains Region: Opportunities and obstacles

Renewable Agriculture and Food Systems ◽

10.1017/s174217051100041x ◽

2011 ◽

Vol 27 (1) ◽

pp. 12-20 ◽

Cited By ~ 25

Author(s):

Patrick M. Carr ◽

Randy L. Anderson ◽

Yvonne E. Lawley ◽

Perry R. Miller ◽

Steve F. Zwinger

Keyword(s):

Crop Rotation ◽

Great Plains ◽

Cover Crops ◽

Cover Crop ◽

Growing Season ◽

Northern Great Plains ◽

Crop Species ◽

Cash Crops ◽

No Till ◽

The Us

AbstractThe use of killed cover crop mulch for weed suppression, soil erosion prevention and many other soil and crop benefits has been demonstrated in organic no-till or zero-till farming systems in eastern US regions and in Canada. Implements have been developed to make this system possible by terminating cover crops mechanically with little, if any, soil disturbance. Ongoing research in the US northern Great Plains is being conducted to identify cover crop species and termination methods for use in organic zero-till (OZ) systems that are adapted to the crop rotations and climate of this semi-arid region. Current termination strategies must be improved so that cover crop species are killed consistently and early enough in the growing season so that subsequent cash crops can be grown and harvested successfully. Delaying termination until advanced growth stages improves killing efficacy of cover crops and may provide weed-suppressive mulch for the remainder of the growing season, allowing no-till spring seeding of cash crops during the next growing season. Excessive water use by cover crops, inability of legume cover crops to supply adequate amounts of N for subsequent cash crops and failure of cover crops to suppress perennial weeds are additional obstacles that must be overcome before the use of killed cover crop mulch can be promoted as a weed control alternative to tillage in the US northern Great Plains. Use of vegetative mulch produced by killed cover crops will not be a panacea for the weed control challenges faced by organic growers, but rather one tool along with crop rotation, novel grazing strategies, the judicious use of high-residue cultivation equipment, such as the blade plow, and the use of approved herbicides with systemic activity in some instances, to provide organic farmers with new opportunities to incorporate OZ practices into their cropping systems. Emerging crop rotation designs for organic no-till systems may provide for more efficient use of nutrient and water resources, opportunities for livestock grazing before, during or after cash crop phases and improved integrated weed management strategies on organic farms.

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Late-seeded cover crops in a semiarid environment: overyielding, dominance and subsequent crop yield

Renewable Agriculture and Food Systems ◽

10.1017/s174217052100020x ◽

2021 ◽

pp. 1-12

Author(s):

John R. Hendrickson ◽

Mark A. Liebig ◽

David W. Archer ◽

Marty R. Schmer ◽

Kristine A. Nichols ◽

...

Keyword(s):

Crop Yield ◽

Great Plains ◽

Cover Crops ◽

Cover Crop ◽

Relative Yield ◽

Warm Season ◽

Species Selection ◽

Northern Great Plains ◽

Cash Crops ◽

Precipitation Timing

Abstract Interest in cover crops is increasing but information is limited on integrating them into crop rotations especially in the relatively short growing season on the northern Great Plains. A 3-yr research project, initiated in 2009 near Mandan, North Dakota, USA, evaluated (1) what impact cover crops may have on subsequent cash crops yields and (2) whether cover crop mixtures are more productive and provide additional benefits compared to cover crop monocultures. The study evaluated 18 different cover crop monocultures and mixtures that were seeded in August following dry pea (Pisum sativum L.). The following year, spring wheat (Triticum aestivum L.), corn (Zea mays L.), soybean (Glycine max L.) and field pea were seeded into the different cover crop treatments and a non-treated control. A lack of timely precipitation in 2009 resulted in a low cover crop yield of 17 g m2 compared to 100 and 77 g m2 in 2008 and 2010, respectively. Subsequent cash crop yield was not affected by late-seeded cover crops. Cool-season cover crop monocultures were more productive than warm-season monocultures and some mixtures in 2008 and 2010. Relative yield total did not differ from one in any cover crop mixture suggesting that overyielding did not occur. Species selection rather than species diversity was the most important contributor to cover crop yield. Cover crops can be grown following short-season cash crops in the northern Great Plains, but precipitation timing and species selection are critical.

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