Johnson et al., 2016). Removal of crop residue reduces soil organic carbon (SOC), and impacts soil productivity. However, the impacts of residue removal rates on soils depend on certain factors such as soil texture, soil topography, initial contents of SOC, tillage, and cropping system (Blanco-Canqui et al., 2013). Water is the most limiting factor for crop production in regions where either irrigation is not available or precipitation is limited (Das et al., 2017). Water stored in the soil profile helps to fulfill the water requirement for following crop in the rotation. Corn residue left behind after corn harvest helps to conserve water in soil (Iqbal et al., 2013) and plays an important role in water conservation and hence increase grain yields where irrigation or precipitation is a limiting factor in crop production (Van Donk et al., 2010; VanLoocke et al., 2012). The long-term adoption of CC could negate the adverse effects of residue removal and increase SOC and improve soil water dynamics, eventually improving crop production and soil productivity (Basche et al., 2016a; Basche et al., 2016b; Kahimba et al., 2008). A study by Chahal and Van Eerd (2018) showed that cover crop increased SOC concentrations by 8.4 to 9.3% and crop yield by 7.9 to 22% compared with no cover crop treatment. Basche and DeLonge (2017) showed that adoption of CC for more than 10 yr improved soil hydrological properties

Integrated crop–livestock systems (ICLSs) can help increase food production while benefiting soils and the environment. This review summarizes recent impacts of ICLSs on crop and livestock production and rural economics and discusses lessons learned in the northern Great Plains (NGP). Research on ICLS conducted in the NGP indicates that the crop residue grazing, swath grazing, and annual forage grazing can positively influence crop production; whereas, livestock performance varies with season, forage nutritive value, and grazing management. Furthermore, ICLSs can reduce the costs and risks of agricultural production. The success of ICLSs in NGP region depends on trade‐offs, planning, economic benefits, policies, regulations, community acceptance, and management skills. The ICLSs could play a strategic role in future agricultural production. The lessons learned from adopting ICLSs in the NGP include the lack of available land for fertilizer (manure) management, that to implement ICLS practices skills and knowledge must be maintained, and ICLS provides an entry point for young farmers and ranchers however capital is needed. These experiences and lessons could be valuable references for producers to adopt ICLSs in the NGP or other regions. Core Ideas Integrated crop–livestock systems positively affect crop production by improving soil health. Common integrated crop–livestock system management techniques can enhance the northern Great Plains crop production. Integrated crop–livestock system livestock performance is impacted by season, forage selection, and management. Integrated crop–livestock systems can increase economic benefits and reduce economic risks. Experiences and lessons in the northern Great Plains could be valuable for other regions to adopt integrated crop–livestock systems.

Field pea (Pisum sativum L.) has been introduced recently as a rotational crop in the semi‐arid region of the northern Great Plains. Very little is known about the response of field pea varieties to management practices such as planting date and seeding rate in this environment. This study was conducted at two locations in 2004 to 2006 to determine the effect of seeding rate on field pea establishment, yield, and yield components. In addition, seeding rates required for economic optimum yield were determined. The study had four varieties with contrasting morphology and six seeding rates ranging from 25 to 90 viable seeds/m2. Increasing seeding rate increased seedling density and seed yield. Harvest index and plant height were relatively constant across seeding rates. Pea plants compensated for low plant populations by producing more pods per plant and more seeds per pod although this compensation mechanism was not enough to maintain high yield at low populations in all environments. Seeding rates that gave best partial net economic returns varied from year to year, but with a trend for lower returns at seeding rates greater than 77 seeds/m2. A target seeding rate of 64 to 77 seeds/m2 is suggested for the region.

Core Ideas Brassica carinata is a new crop in the Northern Great Plains. Best management practices including N fertilizer recommendations should be developed. Seed yield and oil yield were optimized at 84 kg ha–1 of applied N fertilizer. Seed oil concentration decreased linearly at a rate of 0.26 g kg–1 for every 1 kg ha–1 increase in N rate. Economic optimum N rate varied from 60 to 81 kg N ha–1. ABSTRACT Ethiopian mustard (Brassica carinata A. Braun) is a non‐food oilseed crop that has received attention for its potential as a low‐input biofuel feedstock suitable for production in the semiarid regions of the Northern Great Plains (NGP). Because B. carinata is a new crop to the NGP, the best management practices have yet to be developed. The objective of the study was to evaluate the effects of N fertilizer rate on seed yield, seed oil concentration, and oil yield of B. carinata and to determine the economic optimum N fertilizer rates. Field studies were conducted at two locations in South Dakota to evaluate the response of two B. carinata varieties to five N fertilizer rates (0, 28, 56, 84, and 140 kg N ha−1) during the 2015 and 2016 growing seasons. Increasing N fertilizer rate increased seed yield and oil yield, each reaching a peak at 84 kg ha−1 N and then slowly decreasing following a quadratic model. On the other hand, increasing N rate linearly decreased seed oil concentration. The economic optimum N rate ranged from 60 to 81 kg N ha−1 depending on cost of N fertilizer and the price of carinata seed. These results show that the N requirement for B. carinata is lower than that for many crops grown in the NGP, including corn and small grains. These findings confirm that B. carinata requires low N fertility and has the potential for incorporation into cropping systems in the semiarid regions of the NGP.

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Rotating cereal crops [e.g., wheat (Triticum aestivum L.) with a 10-to 21-month summer fallow period (fallow) is a common farming practice in dryland (rainfed) agricultural This article is protected by copyright. All rights reserved. 2 regions. Fallow is associated with several challenges including low precipitation storage efficiency, depletion of soil organic carbon (SOC), loss of soil fertility, little crop residue retention and soil erosion, and few control options for herbicide resistant (HR) weeds. The inability to effectively control HR weeds poses a major challenge to maintaining soil and water conservation practices such as no-till, as some producers are considering tillage to control weeds. Cover crop (CC) integration into wheat-based production systems to replace portions of the fallow period provides an opportunity to increase SOC, improve soil fertility, suppress weeds, and increase profitability of dryland crop production, especially when CCs are used as forage. This forum paper used the North American Great Plains as a model region to review information on (1) challenges of dryland agriculture; (2) integrating CCs in dryland agriculture; (3) benefits, challenges, and limitations of CCs in dryland crop production; (4) management options for CC integration in dryland grain systems; and (5) recommendations for future research efforts. Abbreviations: CC, cover crop; HR, herbicide resistance; NT, no-tillage; SOC, soil organic carbon.

Bioenergy has potential to reduce greenhouse gas (GHG) emissions through sustainable resource development and the use of efficient bioenergy systems (Chum et al., 2011). One of the important components for this system is liquid biofuel. Most common biofuel includes bioethanol derived from corn (Zea mays L.), sugar beet (Beta vulgaris L.), and sugarcane (Saccharum officinarum L.), which is mixed with gasoline, whereas oilseed crops-based biofuel, soybean (Glycine max L. Merr.), consumes high energy due to short hydrocarbon chains, to produce fuel (Perlack, 2005). Carinata (Brassica

Soybean growers in the northern latitudes of the United States plant the crop in a wide range of row spacings although there has been a shift toward wider rows (>50 cm) in some Upper Midwest states in the last 5 years. The objective of this study was to evaluate the impact of row spacing and seeding rate on the performance of soybean and to determine whether these management practices interact to influence soybean yield. A row spacing study was conducted at Aberdeen and Beresford, South Dakota, USA, in 2014 and 2015. The study had two row spacings (19 and 76 cm), four seeding rates (247,000, 333,500, 420,000, and 506,500 seeds ha À1 ), and two soybean varieties at each location. Soybean had greater stand establishment in 19 cm rows (6-10% higher) compared with 76 cm rows. Soybean in 19 cm rows yielded 0.8-10% more than in 76 cm rows depending on the location or year. Seed yield increased with increasing seeding rate with the highest seeding rate of 506,000 seeds ha À1 yielding greatest. The increase in seed yield due to the increase in seeding rate ranged from 3 to 7%. At each location, the longer duration soybean variety yielded higher than the shorter duration variety.