Dryland Spring Wheat Research Articles

Nano-iron and AM fungi inoculation in dryland wheat field: A sustainable alternative to plastic film mulching

ContextPlastic film mulching is a primary cultivation measure in the dryland agricultural areas of northwest China, but comes with the drawback of plastic pollution. To overcome this issue, the biological inoculants such as arbuscular mycorrhizal (AM) with nanotechnology might be a critical pathway, but their positive effects on plants are context-dependent and vary with species, application method, concentration, size, surface charge, and other physio-chemical properties. There is so far limited information available on the combined effects of AM fungi with nanoparticles in agriculture. ObjectivesThis study aimed to investigate the potential of iron nanoparticles (FeNPs) in combination with AMF regarding wheat productivity maintenance and its driving mechanism. MethodsHerein, we used a completely randomized block design for the field experiments in the years 2018 and 2019. We conducted two field experiments using nanopriming of seeds with iron nanoparticles (FeNPs) and AMF in two growing seasons in 2018 and 2019 on wheat (Triticum aestivum L., cv. Longchun29) in the field. Each plot had a 5 m × 5 m total area having 6 rows of 0.2 m spacing and 0.5 m buffer strip among the neighboring plots. There were 8 treatments in the field experiment, and each treatment was repeated 3 times, including four nano iron concentration seed soaking treatments (0 mg L-1, 5 mg L-1, 10 mg L-1, 15 mg L-1) and two inoculation treatments of arbuscular mycorrhizal fungi (inoculated with Gi and non-inoculated). ResultsCombined treatments with arbuscular mycorrhizal fungi and iron nanoparticles led to significant increases in wheat biomass and yield across 2018 and 2019. When compared with control treatment there was an increase of 111% in biomass for the year 2018 and a 102% increase was observed for the year 2019; while the increase in the yield percent when compared to control was 91% in 2018 and 85% in 2019 respectively. Water use efficiency for yield (WUE) increased by 92% in 2018 and 57% in 2019. The colonization rate of AMF + FeNPs 10 mg L-1 treatment increased by 223%, 88%, and 211%, respectively compared with control at the jointing, anthesis, and maturity stage in 2018; and increased by 48%, 37%, and 56% respectively in the year 2019. FeNPs at 10 mg L-1 led to small increases in total organic carbon (TOC), total nitrogen (TN), microbial biomass carbon and nitrogen (MBC), and (MBN), in both growing seasons, and AMF inoculation further significantly increased these carbon fractions by 2.6%, 20%, 21% and 26% in 2018; while 1.3%, 14.8%, 12.5%, and 35% in 2019 respectively. ConclusionThe combined treatments of FeNPs and AMF at an optimal concentration (10 mg L-1) significantly increased net economic income by 229% in 2018 and 138% in 2019 when compared to the control. In this study, wheat aboveground biomass and yield and other related parameters have been improved under field trials, which verified that AMF inoculation alongside FeNPs, can play a beneficial role in promoting dryland spring wheat. ImplicationsTaken together, the co-inoculation with FeNPs and AMF displayed a promising perspective in green production with the potential replacement of plastic film mulching in semiarid dryland regions.

Yield components, reproductive allometry and the tradeoff between grain yield and yield stability in dryland spring wheat

Abstract Yield improvement for smallholder farmers in developing countries via crop breeding has been slow, in part because breeders have focused primarily on higher yields rather than stability of yield across environments. We investigated the relationships between (i) grain yield and yield-component traits, (ii) grain yield and yield stability, and (iii) reproductive (R) and vegetative (V) biomass in a field experiment with 18 spring wheat genotypes varying from landraces to recently-released breeding lines in a semiarid region under three different levels of precipitation. Genotypic differences in grain yield varied with the environment. The relationship between grain yield and yield components was also dependent on the environment, making it difficult to identify early-screening parameters for use in breeding programs. A genotype main effects and genotype by environment interaction effect analysis (GGE) showed a negative relationship between mean grain yield and yield stability across environments. There were significant differences among genotypes in the allometric exponent of the R-V relationship (slope of the log R – log V relationship). For the three highest yielding but less stable genotypes, this slope value was > 1, while the five lowest yielding, but more stable genotypes, it was

Nitrogen and potassium fertilization for improved dryland spring wheat grain yield and quality

Like all cereals, wheat requires potassium (K) for optimal growth and development. This study aimed to better understand the importance of K nutrition for yield and quality of dryland hard red spring wheat. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/745.

Adapting the nitrogen replacement approach to dryland spring wheat in the Pacific Northwest

The objective of this article is to summarize results of a study conducted in eastern Oregon to define the critical protein levels for dark northern spring and soft white spring wheats and their fertilizer nitrogen equivalent values. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/494.

Impact of tillage, seeding rate and seeding depth on soil moisture and dryland spring wheat yield in Western Siberia

Dryland crop production in the Western Siberian grain belt is an important contribution to Russia's growing importance as a global wheat supplier. After the break-up of the Soviet Union significant changes in agricultural structures with recent intensification on cropland took place. Together with climate change predictions of drier and warmer growing conditions, this leads to upcoming challenges for water-limited crop production in the south of the Asian part of the Eurasian grain belt. A full-factorial field trial was conducted on a farmer's field to test adaptations of tillage (usual conventional tillage ‘CT’ vs. no-till ‘NT’), seeding depth (usual deep 6.5cm vs. shallow 4.5cm) and seeding rate (usual high 600grainsm−2 vs. reduced 450grainsm−2) for potential to increase water use efficiency and grain yield in spring wheat. Results from two above-average wet and cold growing seasons showed significant better soil water storage of NT (+40%) and no adverse effect on spring wheat grain yield and grain quality for the study site in the south of Western Siberia. Variations in seeding rate of the regional variety were compensated by different manifestation of the individual yield components: high seeding rates resulted in more reproductive ears per m2 whilst reduced seeding rates produced more grains per ear. The traditional deep seed placement was found to be beneficial for NT but shallow placement was advantageous with CT. The highest yields of 3.19 and 3.82tha−1 were observed in 2014 with NT, deep seed placement and high seeding and in 2015 with NT, deep seed placement and reduced seeding rate, respectively. The on-farm field trial results revealed, that NT can be successfully used in dryland cropping under current agro-climatic conditions of Western Siberia and is a promising perspective under climate change predictions.

Fall Rye Reduced Residual Soil Nitrate and Dryland Spring Wheat Grain Yield

Core Ideas Fall rye reduced pre‐plant nitrate by 2 to 18 times compared with tillage radish. Fall rye reduced dryland spring wheat grain yield by 38 to 58% compared with tillage radish. Pre‐plant soil NH4–N plus NO3–N explained 93% of spring wheat grain yield variability. Limited information about how cover crop management impacts the agronomic performance of succeeding annual crops in semiarid regions constrains cover crop utilization. Therefore, over 2 yr we quantified how cover crop species (fall rye [Secale cereale L. ‘AC Remington’] or oilseed radish [Raphanus sativus L. ‘Tillage radish’]) and nutrient source (compost or inorganic fertilizer) affected cover crop biomass and N uptake, soil nitrate N (NO3–N) and ammonium N (NH4–N), and the agronomic performance of the succeeding spring wheat (Triticum aestivum L.) test crop. Fall rye reduced pre‐plant NO3–N by 2 to 18 times compared with oilseed radish, and reduced spring wheat grain yields by 38 to 58% compared with amended soils with no cover crop and oilseed radish. Inorganically fertilized soils led to 21% greater pre‐plant soil NO3–N concentrations than the compost‐amended soil in 2013–2014 but nutrient source did not significantly affect NO3–N concentrations in 2014–2015. A quadratic function explained 93% of the variability between pre‐plant soil NH4–N plus NO3–N (0–7.5‐cm depth) and spring wheat grain yield in 2014, indicating that the N supply limited spring wheat grain yield. We conclude that fall rye scavenged residual NO3–N better than oilseed radish during the non‐growing season, particularly during the spring period when this perennial species assimilates N, but under semiarid conditions it may decompose and mineralize too slowly to supply N at the right time for the subsequent crop, while oilseed radish tended to boost spring wheat grain yield.

Relative Efficacy of Liquid Nitrogen Fertilizers in Dryland Spring Wheat

The study was conducted in 2012 and 2013 at three locations in North Central and Western Montana (total of 6 site-years) to evaluate the relative efficacy of three liquid nitrogen (N) fertilizer sources, urea ammonium nitrate (UAN, 32-0-0), liquid urea (LU, 21-0-0), and High NRGN (HNRGN, 27-0-0-1S), in spring wheat (Triticum aestivumL.). In addition to at-seeding urea application at 90 kg N ha−1to all treatments (except for the unfertilized check plot), the liquid fertilizers were applied utilizing an all-terrain vehicle- (ATV-) mounted stream-bar equipped sprayer at a rate of 45 kg N ha−1at Feekes 5 growth stage (early tillering). Three dilution ratios of fertilizer to water were accessed: 100/0 (undiluted), 66/33, and 33/66. The effects of N source and the dilution ratio (fertilizer/water) on N uptake (NUp), N use efficiency (NUE), spring wheat grain yield (GY), grain protein (GP) content, and protein yield (PY) were assessed. The dilution ratios had no effect on GY, GP, PY, NUp, and NUE at any of the site-years in this study. Taking into account agronomic and economic factors, LU can be recommended as the most suitable liquid N fertilizer source for spring wheat cropping systems of the Northern Great Plains.

Net Returns from Terrain‐Based Variable‐Rate Nitrogen Management on Dryland Spring Wheat in Northern Montana

Agricultural producers can use variable‐rate application technology to vary N fertilizer within fields. This study was conducted to estimate changes in net returns from implementation of variable‐rate N management (VNM) on hard red spring wheat (Triticum aestivum L.) in a summer‐fallow region in northern Montana. Net return from uniform N management (UNM) traditionally used by producers was compared with that from VNM in eight dryland fields between 1994 and 2004. Field experiments consisted of a replicated series of four to six N rates applied within strips oriented with the length of each field. Management zones (MZs) were created by dividing the fields into upper slopes, south‐facing middle slopes, north‐facing middle slopes, and lower slopes. Nitrogen recommendations for MZs were based on soil N testing and expected yields. Grain yield data were obtained using a production‐size combine equipped with a yield monitor. Mean grain protein and yield were similar between VNM and UNM. Yield differences were <223 kg ha−1 and averaged only 18 kg ha−1. Grain yield did not differ significantly among N rates within MZs. In seven of the eight sites, net returns from VNM were up to US$27.97 ha−1 less than from UNM and were not profitable if Environmental Quality Incentive Program payments of US$6.36 ha−1 were considered as part of net income. Little evidence existed that VNM based on constructed MZs and predetermined N recommendations improves grain yields and profits or reduces N use in water‐limited, summer‐fallow systems of northern Montana.

A probabilistic Bayesian framework for progressively updating site-specific recommendations

The goal of this research was to create an agricultural adaptive management framework that enables the probabilistic optimization of N fertilizer to achieve maximized net returns under multiple uncertainties. These uncertainties come in the form of bioclimatic variables that drive crop yield, and economic variables that determine profitability. Taking advantage of variable rate application (VRA), spatial monitoring technologies, and historical datasets, we demonstrate a comprehensive spatiotemporal modeling approach that can achieve optimal efficiency for the producer under such uncertainties. The utility of VRA fertilizer research for producers is dependent upon a localized accurate understanding of crop responses under a range of possible climatic regimes. We propose an optimization framework that continuously updates by integrating annual on-site experiments, VRA prescriptions, crop prices received, input prices, and climatic conditions observed each year under a dryland spring wheat (Triticum aestivum) cropping system. The spatio-temporal Bayesian framework used to assimilate these data sources also enables calculation of the probabilities of economic returns and the risks associated with different VRA strategies. The results from our simulation experiments indicated that our framework can successfully arrive at optimum N management within 6–8 years using sequential Bayesian analysis, given complete uncertainty in water as a driver of crop yield. Once optimized, the spatial N management approach increased net returns by $23–25 ha−1 over that of uniform N management. By identifying small-scale targeted treatments that can be merged with VRA prescriptions, our framework ensures continuous reductions in parameter uncertainty. Thus we have demonstrated a useful decision aid framework that can empower agricultural producers with site-specific management that fully accounts for the range of possible conditions farmers must face.

Response of dryland spring wheat yield to elevated CO<SUB>2</SUB> concentration and temperature by APSIM model

Response of dryland spring wheat yield to elevated CO<SUB>2</SUB> concentration and temperature by APSIM model

Effects of tillage on microbial populations associated to soil aggregation in dryland spring wheat system

Tillage may influence the microbial populations involved in soil aggregation. We evaluated the effects of no till (NT) and conventional tillage (CT, tillage depth about 7 cm) continuous spring wheat system on culturable heterotrophic bacterial communities predominant in microaggregates (0.25–0.05 mm) and on soil-aggregating basidiomycete fungi in aggregate-size classes (4.75–2.00, 2.00–0.25, and 0.25–0.05 mm) at 0–20 cm depth of a Williams loam (fine-loamy, mixed, Typic Argiustolls) in dryland Montana, USA. Enzyme-linked immunosorbent assay used to quantify antigenic response to basidiomycete cell walls, was higher in NT than in CT in 4.75–2.00 mm size class in 2007 and higher in all classes and years at 0–5 cm depth, but was not different between tillage, years, and classes at 5–20 cm. The culturable bacteria from microaggregates were subjected to a soil sedimentation assay to determine their soil binding capability. The proportion of isolates which can function as soil aggregators was higher in NT than in CT at 0–5 cm but was not different at 5–20 cm. Our results provide a first insight into the beneficial effects of dryland NT compared to CT in reducing soil disturbance and residue incorporation and enriching the proportion of microorganisms responsible for aggregation, especially at the soil surface.

Tillage Method and Sowing Rate Relations for Dryland Spring Wheat, Barley, and Oat

Tillage Method and Sowing Rate Relations for Dryland Spring Wheat, Barley, and Oat

Tillage Method and Sowing Rate Relations for Dryland Spring Wheat, Barley, and Oat

Some farmers in the Inland Pacific Northwest (PNW) have reported lower grain yield of spring cereals with no‐till (NT) compared with conservation tillage (CT). A 4‐yr field study was conducted in a 300‐mm annual precipitation zone to determine tillage method and sowing rate effects on seed‐zone water, seed‐zone temperature, plant stand, grain yield, grain yield components, and straw production for three spring‐sown cereal species. Wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and oat (Avena sativa L.) were sown at 120, 200, and 280 seeds m−2 in a split plot design with NT and CT as main plots and sowing rate × cereal species combinations as subplots. Factors other than tillage method (i.e., drill, sowing date, fertilizer rate, sowing depth) were held constant. There were no differences in plant stand between NT and CT, but grain yield was reduced by 5% in NT in part because of less water in the seed zone compared with CT during early plant development. Disruption of capillary continuity with CT appeared to restrict upward movement of water, resulting in greater retention of water in the seed zone underlying the depth of tillage. Grain yield was not affected by sowing rate for any crop species because increased number of heads per unit area (HPU) and kernels per head (KPH) consistently compensated for reduced plant stand density. With precise seed placement, sowing rate of spring cereals can be reduced by 50% or more from rates commonly used.

Effects of Chloride Fertilization on Wheat (Triticum aestivum L.) Productivity in the Sandy Pampas Region, Argentina

The soils from the sandy Pampas region (Argentina) are coarse‐textured Mollisols with high to very high extractable K levels. However, in several KCl fertilization field trials, wheat (Triticum aestivum L.) grain yield and alfalfa (Medicago sativa L.) dry matter production increments have been reported. Our objective was to determine the contribution of Cl− fertilization on dryland spring wheat productivity. The study was performed during the 2001 and the 2002 growing seasons on 10 experimental sites establishing 14 treatments in completely randomized blocks with four replications: Cl− fertilization rates (0, 23, 46, and 69 kg ha−1), Cl− fertilizer sources (KCl and NH4Cl), and crop disease control (with and without fungicide applications during stem elongation). Chloride fertilization increased grain yields in 50% of the sites independently of the fertilizer source and the fungicide treatments. Averaged over the 10 locations, the grain yield response to Cl− fertilization was of 253 kg ha−1, and it was mostly explained by a greater number of grains per square meter. Soil Cl− levels >13.2 mg kg−1 (0.0 to 0.2 m) were adequate for maximum grain yields. Foliar fungicide application also improved wheat grain production, enlarging the single weight of the grains. In the absence of water, N, P, and S deficiencies, the fertilization with 23 to 46 kg ha−1 of Cl−–containing fertilizers after the emergence of wheat crops is a recommended practice for achieving high‐yielding crops in the sandy Pampas region of Argentina.

Tillage and Nitrogen Fertilization Influences on Grain and Soil Nitrogen in a Spring Wheat–Fallow System

Spring wheat (Triticum aestivum L.) is generally produced in the northern Great Plains using tillage and a crop–fallow system. This study evaluated the influence of tillage system [conventional‐till (CT), minimum‐till (MT), and no‐till (NT)] and N fertilizer rate (0, 22, and 45 kg N ha−1) on grain N, grain N removal from cropping system, and changes in residual postharvest soil NO3–N during six rotation cycles of a dryland spring wheat–fallow (SW–F) cropping system. Grain N concentration increased with increasing N rate and was higher with CT (33.3 g kg−1) than with NT (32.3 g kg−1) at 45 kg ha−1 N rate. Grain N removal per crop was greater with CT (70 kg N ha−1) and MT (68 kg N ha−1) than with NT (66 kg N ha−1) and tended to increase with increasing N rate, but varied with rotation cycle. Total grain N removal in six rotation cycles was in the order: CT > MT > NT. Total grain N removal by six SW crops was increased by N fertilization, with only 21 and 17% of the applied N removed in the grain for the 22 and 45 kg ha−1 N rates, respectively. Postharvest soil NO3–N levels in the 150‐cm profile varied with N rate and rotation cycle, with residual NO3–N increasing during consecutive dry crop cycles. In contrast, some leaching of NO3–N below the SW root zone may have occurred during wetter crop cycles. Soil profile NO3–N levels tended to be greater with CT and MT than with NT. Variation in precipitation during rotation cycles and N fertilization impacted grain N removal and residual soil NO3–N levels more than tillage system within this SW–F cropping system.

Implementing and conducting on-farm weed research with the use of GPS

Abstract The adoption of precision technologies that spatially register measurements using global positioning systems (GPS) greatly facilitates conducting large-scale on-farm research by farmers. On-farm experiments that utilize producer equipment include variations in agronomic practices that occur in situations where we want to predict the effect of inputs on yield. The domain of inference for such on-farm studies therefore more closely matches that desired by researchers. To investigate the feasibility of on-farm research using GPS, a study was conducted to evaluate the potential benefit of site-specific weed management. The study utilized producer-maintained field-scale equipment on four Montana farms in dryland spring wheat production. Paired site-specific and whole-field herbicide treatment areas were established in 0.9 to 1.9-ha blocks using consultant weed maps and a geographic information system (GIS). Yield was unaffected by herbicide treatment strategy (site-specific or broadcast). Minimal dete...

Spring Wheat Response to Tillage System and Nitrogen Fertilization within a Crop–Fallow System

Spring wheat (Triticum aestivum L.) production in the northern Great Plains generally utilizes conventional tillage systems. A 12‐yr study evaluated the effects of tillage system [conventional‐till (CT), minimum‐till (MT), and no‐till (NT)], N fertilizer rate (0, 22, and 45 kg N ha−1), and cultivar (Butte86 and Stoa) on spring wheat grain yields in a dryland spring wheat–fallow rotation (SW–F). Butte86 yields with CT exceeded NT yields in five out of 12 years with 0 and 22 kg N ha−1 applied, and four years with 45 kg N ha−1 applied. Stoa yields with CT exceeded NT yields in three out of 12 years with no N applied, four years with 22 kg N ha−1 applied, and only one year with 45 kg N ha−1 applied. Yields with NT exceeded those with CT in one year. Most years, yields with MT equaled those with CT. Responses to N tended to be greatest in years when spring soil NO3–N was lowest. Positive yield responses to N fertilization with CT occurred in three years with Butte86 and two years with Stoa; with MT, four years with Butte86 and two years with Stoa; and with NT, five years with Butte86 and three years with Stoa. Cultivars were not consistent in their response to tillage and N fertilization. These results indicate that farmers in the northern Great Plains can successfully produce spring wheat in a SW–F system using MT and NT systems, but yields may be slightly reduced when compared with CT systems some years.

Spring Wheat Response to Tillage and Nitrogen Fertilization in Rotation with Sunflower and Winter Wheat

Spring wheat (Triticum aestivum L.) is a major crop in the northern Great Plains that is generally grown following a 21‐mo fallow period. A 12‐yr study was conducted to determine the effects of tillage system [conventional‐till (CT), minimum‐till (MT), and no‐till (NT)], N fertilizer rate (34, 67, and 101 kg N ha−1), and cultivar (Butte86 and Stoa) on spring wheat yields within a dryland spring wheat (SW)–winter wheat (WW)–sunflower (Helianthus annuus L.) (SF) rotation. Grain yield responses varied with tillage system, N fertilizer rate, cultivar, and year as indicated by significant tillage × N rate × year and N rate × cultivar × year interactions. In years with >260 mm total plant available water (TPAW) but <400 mm TPAW, NT grain yields were greater than those with CT at the highest N rate, with similar trends at the medium and low N rates. When TPAW exceeded 400 mm, grain yields for CT were generally greater than for NT at the medium N rates. The greatest 12‐yr average grain yield (1727 kg ha−1) was obtained with NT and application of 101 kg N ha−1. Grain yields were lowest during years when TPAW was <300 mm, with only small responses to tillage and N treatments. Cultivars responded similarly to N fertilization in years with >300 mm TPAW, with Butte86 yielding more than Stoa in 6 out of the 12 yr. Soil NO3–N levels increased in the root zone following three consecutive drought years, but had declined to initial year levels by the end of the study. These results indicate that farmers in the northern Great Plains can produce SW following SF in annual cropping systems that do not include a fallow period, particularly if NT or MT systems are used with adequate N fertilization.

Sunflower Response to Tillage and Nitrogen Fertilization under Intensive Cropping in a Wheat Rotation

Sunflower (Helianthus annuus L.) is a warm‐season, intermediate water‐use crop that can add diversity to dryland crop rotations. Reduced tillage systems may enhance sunflower yield in intensive cropping systems. A 12‐year study was conducted to determine how sunflower cultivars of early and medium maturity respond to tillage system (conventional‐till, CT; minimum‐till, MT; no‐till, NT) and N fertilization (34, 67, and 101 kg N ha−1) within a dryland spring wheat (Triticum aestivum L.)–winter wheat–sunflower rotation. Averaged across N rates, cultivars, and years, sunflower seed yields were greater with MT (1550 kg ha−1) than with NT (1460 kg ha−1) and CT (1450 kg ha−1). Increasing N rate above 34 kg N ha−1 generally increased grain yield, but varied from year to year. The tillage × N interaction showed that the highest seed yields were obtained with NT (1638 kg ha−1) and MT (1614 kg ha−1) at 101 kg N ha−1. Total plant‐available water (TPAW) of <350 mm greatly reduced sunflower yield potential, due to water stress, compared with yields for 350 to 500 mm of TPAW. TPAW > 500 mm did not result in increased sunflower yields over those with 350 to 500 mm TPAW. Yield differences between cultivar maturity classes varied from year to year and with tillage and N level. At the lowest N rate, weeds were more problematic in NT than in CT and MT plots. More N fertilizer may be needed with NT to optimize sunflower yields than with CT and MT, because of less residual soil NO3–N with NT. Results indicate that producers in the northern Great Plains can use sunflower successfully in annual cropping systems, particularly if MT and NT are used with adequate N fertilization.

Dryland Winter Wheat Response to Tillage and Nitrogen within an Annual Cropping System

Winter wheat (Triticum aestivum L.) can add diversity to dryland crop rotations in the northern Great Plains, but it is susceptible to winterkill in low surface residue environments. A 12‐year study was conducted to determine the response of two winter wheat cultivars, Roughrider and Norstar, to tillage system (conventional‐till, CT; minimum‐till, MT: and no‐till, NT) and N fertilizer rate (34, 67, and 101 kg N ha−1) in a dryland spring wheat–winter wheat–sunflower (Helianthus annuus L.) rotation. Grain yields were greater with MT (1968 kg ha−1) and NT (2022 kg ha−1) than with CT (1801 kg ha−1), but tillage system effects on grain yield varied among years. Increasing N rate from 34 kg N ha−1 to 67 kg N ha−1 increased grain production from 1844 to 1953 kg ha−1, but yield response to N rate varied among years. The greatest overall grain yield (2111 kg ha−1) was obtained with NT and application of 101 kg N ha−1. Grain yields were lowest during years when plant‐available water (PAW) was <300 mm. In years with >400 mm PAW, leaf spot disease incidence was greatest, particularly at the lowest N rate with NT. Application of adequate N reduced the disease incidence in all tillage treatments. Cultivar differences were significant 3 out of 12 years, but not consistent. Winterkill was a factor for both cultivars in only 1 year in the CT and MT plots. Winter wheat performed well as a rotational crop in this cropping system when using MT and NT systems and adequate N fertility. Our long‐term results indicate that producers in the northern Great Plains can use winter wheat successfully in annual cropping systems that do not include a fallow period, particularly if NT is used with adequate N fertilization.