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Crop rotations in the northern Great Plains of North America increasingly include corn (Zea mays L.) and soybean (Glycine max (L.) Merr.). Use of cover crops, while less extensive, is also increasing given their purported agronomic and environmental benefits. To date, soil responses to the inclusion of corn, soybean, and cover crops in rainfed cropping systems have not been well documented in the region. Therefore, soil properties were evaluated 6 years after establishment of three crop rotations (spring wheat (Triticum aestivum L.)–soybean (SW–S), spring wheat–corn–soybean (SW–C–S), and spring wheat–corn–cover crop (SW–C–cc)) each split by no and minimum tillage on a Dark Brown Chernozem near Mandan, ND, USA. Soil responses to treatments were subtle and exclusive to the 0–7.6 cm depth. Soil pH was lower in SW–S than SW–C–cc (5.28 vs. 5.48; P = 0.05), SO4-S was greater under SW–C–cc than SW–C–S (13.4 vs. 11.6 g S kg−1; P = 0.03), exchangeable K was greater under SW–C–S and SW–C–cc than SW–S (0.83 cmol kg−1 vs. 0.52 cmol kg−1; P = 0.05), and water-stable aggregates were greater in SW–S than SW–C–S (26% vs. 19%; P = 0.08). Soil organic carbon (SOC) and total N did not differ among crop rotations or between tillage treatments, while particulate organic matter N was greater under no tillage compared to minimum tillage (P = 0.08). Between 2012 and 2018, soil pH decreased and SOC increased under SW–C–S. Frequent monitoring of near-surface soil conditions in rotations with soybean every other year is recommended. Furthermore, innovative management practices are needed to enhance soil C and N fractions in rotations with full-season cover crops. [ABSTRACT FROM AUTHOR]

Integrated crop–livestock (ICL) systems have shown potential to provide a variety of environmental benefits including soil carbon (C) increases relative to conventional row cropping systems. However, studies documenting C dynamics of ICL systems in the northern Great Plains are lacking relative to other agroecosystems. Soil carbon dioxide (CO2) efflux, crop biomass, and soil organic matter (SOM) pools were monitored over 3 years in an ICL rotation (corn [Zea mays L.]/soybean [Glycine max L.]–spring wheat [Triticum aestivum L.] + cover crop–cover crop) with fall grazing, a conventional cropping system rotation (corn–spring wheat–soybean) and fall grazed and ungrazed mixed‐grass pasture near Mandan, ND. Cropped treatments were under no‐till management. Annual aboveground crop residue biomass C was similar in the ICL and conventional systems, while less in the grazed pasture (4.18, 3.83, and 1.21 Mg C ha−1 year−1 respectively; p = 0.039). Annual soil CO2 efflux was greater in the ICL, grazed, and ungrazed pasture systems than the conventional system (8.05, 8.73, 8.25, and 5.81 Mg C ha−1 year−1, respectively; p < 0.001). Among crop phases in the ICL and conventional cropping systems, cover crops contributed to greater CO2 efflux in the spring and fall. SOM and C mineralization were greater at 0–5 cm in the ICL system compared to the conventional cropping system (6.6% vs. 6.3%, p = 0.028 and 248 vs. 184 mg CO2–C kg−1, p < 0.001, respectively). Interseeded cover crops in ICL systems can contribute increased root respiration and enhanced SOM pools relative to conventional cropping systems under semiarid conditions. Core Ideas: Soil carbon (C) dynamics in integrated crop–livestock (ICL) systems are not well understood.Soil carbon dioxide (CO2) efflux and labile pools of soil organic matter (SOM) were evaluated over 3 years.Soil CO2 efflux was greater in the ICL system compared to conventional cropping.SOM and C mineralization were also greater in the ICL system compared to conventional cropping.Interseeded cover crops in ICL systems can enhance soil C pools and biological activity. [ABSTRACT FROM AUTHOR]

The increase in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in rainfed cropping systems of the northern Great Plains (NGP) has altered the delivery of ecosystem services from agricultural land. To date, there is limited understanding about how these crops affect the carbon (C) balance of cropping systems in the region when included in a short rotation window. This study sought to quantify C balance of a spring wheat (Triticum aestivum L.)–corn—soybean rotation under no‐tillage management using eddy covariance (EC) techniques. Paired field sites with the same soil type near Mandan, ND, were used for the study. Annual net ecosystem production (NEP) by crop was –34, 120, and 7 g C m–2 y–1 for spring wheat, corn, and soybean, respectively. Carbon removed in grain over the rotation was less than a third of C lost by ecosystem respiration (ER) (210 vs. 674 g C m–2 y–1). After accounting for grain C removal, net ecosystem carbon balance (NECB) was –164, –253, and –121 g m–2 y–1 for spring wheat, corn, and soybean, respectively, with a mean NECB of –179 ± 39 g C m–2 y–1 (P =.043; t test for difference from zero), implying the rotation was a net C source. Time associated with active crop growth each year was 27% for spring wheat, 41% for corn, and 28% for soybean. Management strategies that lengthen the period of biomass growth may mitigate C loss from spring wheat–corn–soybean rotations in the NGP. Core Ideas: Eddy covariance methods were used to quantify CO2 fluxes from a wheat–corn–soybean rotation. Annual net ecosystem production was negative for wheat, positive for corn, and near zero for soybean.Carbon removed in grain was less than a third of carbon lost by ecosystem respiration.Net ecosystem carbon balance for the rotation was negative, implying carbon loss. [ABSTRACT FROM AUTHOR]

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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. [ABSTRACT FROM AUTHOR]

Agricultural land management may influence crop nutritional quality. However, few studies have explored potential connections between crop quality with different land management strategies. We analyzed mineral and crude protein concentrations in spring wheat grain (Triticum aestivum L.) samples from a study in Mandan, ND conducted from 2006 to 2014. The study introduced a perennial forage phase into an annual spring wheat cropping system, in three to four replicates, and previously found yield benefits and enhanced soil parameters in the perennial forage treatments. We determined whether integrating a perennial forage phase into continuous wheat would also affect crop nutritional quality by measuring wheat grain mineral and protein concentrations. Crude protein concentration was greater (p <.05) when wheat followed alfalfa (Medicago sativa L.) and increased linearly after 2–5 yr of established alfalfa. We observed comparable wheat grain crude protein and mineral concentrations between continuous annually fertilized wheat and unfertilized wheat following perennial forages. Negative correlations (p <.001) were observed between wheat grain yield and crude protein, potassium (K), magnesium (Mg), nickel (Ni), phosphorus (P), sulfur (S), and zinc (Zn) concentrations. Discriminate multivariate analyses showed, with 96% predictive accuracy, that differences in crude protein and mineral concentration were largely driven by year of wheat harvest. Differences between harvest years were likely due to timely precipitation at critical Growth Stage 3, during spikelet development. Study outcomes highlighted the important role of perennial forages and environmental factors to influence protein and mineral concentration in spring wheat grain. Core Ideas: Perennial forages benefit annual cropping systems. Wheat grain samples were analyzed for mineral and protein concentration. Protein was greater when wheat followed alfalfa versus intermediate wheatgrass. Grain quality was similar between annual cropping and wheat following perennials. Grain mineral and protein concentrations were influenced by environmental factors. [ABSTRACT FROM AUTHOR]

While crop residues could provide an additional source of revenue for agricultural producers, there are concerns that harvesting these residues could have negative effects on productivity and economic returns. Although crop residue harvest effects have been studied in wetter areas, including the U.S. Corn Belt and Southeast, there have been few studies in more arid areas. The objective of this analysis was to quantify intermediate‐term (6‐yr) effects of crop residue harvest on crop productivity and economic returns for different biomass harvest intensities and methods, and for different practices aimed at mitigating negative effects of residue harvest in the U.S. Northern Great Plains. Crop rotation treatments included spring wheat (Triticum aestivum L.)–dry pea (Pisum sativum L.), W–P; spring wheat–dry pea/cover crop mix, W–P/CC; and spring wheat–dry pea–corn (Zea mays L.), W–P–C. Biomass removal treatments included no biomass removal, bale and remove wheat straw, bale and remove residues from each crop, and graze all crop residues. Significant corn yield reductions occurred when baling crop residues, but not with grazing. However, significant spring wheat yield reductions occurred with grazing in the W–P rotation. Grazing may be more suited to the W–P–C rotation than the W–P or W–P/CC rotations as the breakeven grazing price was lower in this rotation, and the grazing treatment in this rotation had both relatively high economic returns and low economic risk over the study period. [ABSTRACT FROM AUTHOR]

Increasing crop diversity has been proposed to increase the sustainability of cropping systems. If producers are to adopt these systems, they should also be economically viable. In this study conducted near Mandan, North Dakota, four no-till cropping systems with varying levels of crop diversity were evaluated over a 12-yr period to quantify system effect on crop productivity, input use, production costs, and economic risks and returns. Cropping system treatments included a small grain–fallow rotation (SG–Fallow) and a continuous spring wheat (Triticum aestivum L.) rotation (Cont SW) as baseline low-diversity rotations, a small grain–winter wheat (T. aestivum L.)–sunflower (Helianthus annuus L.) rotation (SG–WW–Sun), a 5-yr rotation (Five Year) and a dynamic rotation (Dynamic). The SG–Fallow rotation was significantly less productive and less profitable on average than the other rotations, as measured by gross returns and net returns, respectively. However, SG–Fallow also used significantly less inputs than the other rotations. Production costs for the Cont SW and SG–WW–Sun rotations showed a significant increasing trend over time, while production costs for the Five Year rotation showed a significantly lower and slight decreasing trend over the period, with cost trends for the SG–Fallow and Dynamic rotations intermediate to these. Net returns tended to increase and relative economic risk tended to decrease as crop diversity increased from SG–Fallow and Cont SW to SG–WW–Sun, Five Year and the Dynamic system. Results from this study suggest that more diverse rotations can maintain or increase crop productivity and enhance economic viability. [ABSTRACT FROM AUTHOR]

In semiarid dryland farming regions, No-till and intensified crop rotations may improve water use. Our objective was to determine water use efficiency (WUE) and precipitation use efficiency (PUE) for spring wheat (Triticum aestivum L.; SW) grown in crop sequences representing different levels of intensification, under minimum (Min-till) or No-till. Root zone (0-122 cm) water at planting (SWP) was 2.76 cm higher for two- and three-phase sequences under Min-till than continuous spring wheat (CSW), and sequences with fallow averaged 2.65 cm higher than those without. Conversely, SWP was unaffected by sequence under No-till, with less effect of fallow. Root zone water at harvest was unaffected by the number of crop phases or fallow under Min-till. However, values for CSW exceeded the two- or three-phase sequences by 1.57 and 2.53 cm under No-till, and sequences without fallow averaged 1.52 cm more than those with fallow. The highest WUE (8.4 kg grain ha-1 mm-1 water) was observed when SW was grown in three-phase sequences compared with 7.7 kg grain ha-1 mm-1 water, for CSW and SW-fallow. Spring wheat under Min-till had higher WUE in sequences with fallow, but no effects of fallow occurred with No-till. The lowest PUE (near 3 kg grain ha-1 mm-1 precipitation) and no effects of tillage were found in sequences with fallow. However, SW in continuously cropped sequences had PUE between 5.5 and 6.4 kg grain ha-1 mm-1 precipitation and was higher under No-till. Both WUE and PUE are affected by intensification but may also be influenced by patterns of weather.

Many integrated crop-livestock system (ICL) studies have been conducted, but few report cattle performance and forage nutrients. Here, we report one year of cattle weight gains for Angus yearling heifers and steers grazing ICL plots (ICL) or tame grass pastures (PAS) in four replicates. Five yearlings (avg. BW 390 ± 26 kg) were randomly assigned to graze each plot while provided ad libitum water and trace mineral salt. Cattle assigned to ICL grazed three crop rotations: 1) corn interseeded with soybean (C/S), 2) spring wheat interseeded with cover crop and 3) cover crop planted into spring wheat from the previous year. Yearlings in ICL were stocked first on green C/S, grazing an average of 60 days. Beginning C/S biomass was 1,827 ± 638 g m-2, yearling end BW was 465 ± 34 kg and ADG 1.28 ± 0.27 kg. Yearlings then grazed residual cover crop growth, averaging additional 42 d grazing while supplemented with a ration of baled cover crop forage, wheat straw, and corn. Ration intake averaged 15.35 ±0.6 kg animal-1 d-1. Final BW of ICL yearlings on cover crops averaged 499 ± 34 kg, ADG of 0.79 ± 0.29 kg. Yearlings assigned PAS were provided 1,911 ± 162 g m-2 at the beginning of grazing for 69 days, had final BW 443 ± 35 kg, ADG of 1.01 ± 0.22. Forage nutrient analyses are reported in Table 1, showing that individual crops are similar in ADF and TDN, but vary in crude protein content. Performance of ICL cattle exceeded that of PAS while on corn and soybean but decreased ICL performance while grazing cover crop was likely due to extreme cold weather at the time of grazing. Nutrient values reported here can be used to plan and predict cattle growth while grazing crop residues instead of pastures. [ABSTRACT FROM AUTHOR]

A correction is presented to the article "Perennial forages influence mineral and protein concentrations in annual wheat cropping systems."