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Simple Summary: The spread of invasive wild pigs across the United States has been successfully slowed due to the establishment of a national management program. In this paper, we study the effectiveness of the national program by modeling the spread of wild pigs in the absence of intervention. Further, we use the models to assess the value of resources safeguarded from the threat of wild pigs. Our findings indicate that, on average, invasive wild pigs were prevented from spreading to 724 counties, and USD 40.2 billion in resource value was safeguarded over the first eight years of the program. Continuation of the program will deliver additional benefits and further research is critical to understand its comprehensive economic effects. Wild pigs (Sus scrofa) are one of the most destructive invasive species in the US, known for causing extensive damage to agricultural commodities, natural resources, and property, and for transmitting diseases to livestock. Following the establishment of the National Feral Swine Damage Management Program (NFSDMP) in 2014, the expansion of wild pig populations has been successfully slowed. This paper combines two modeling approaches across eight separate models to characterize the expansion of wild pig populations in the absence of intervention by the NFSDMP and forecasts the value of a subset of resources safeguarded from the threat of wild pigs. The results indicate that if wild pigs had continued spreading at pre-program levels, they would have spread extensively across the US, with significant geographic variation across modeling scenarios. Further, by averting the threat of wild pigs, a substantial amount of crops, land, property, and livestock was safeguarded by the NFSDMP. Cumulatively, between 2014 and 2021, wild pig populations were prevented from spreading to an average of 724 counties and an average of USD 40.2 billion in field crops, pasture, grasses, and hay was safeguarded. The results demonstrate that intervention by the NFSDMP has delivered significant ecological and economic benefits that were not previously known. [ABSTRACT FROM AUTHOR]

Stink bugs (Hemiptera: Pentatomidae), including the exotic Halyomorpha halys (Stål), Nezara viridula (L.), and other indigenous species, are pests that damage a variety of agricultural crops. At a study site in the southeastern United States, we measured the density of stink bug species and patterns of parasitism and predation on corn, cotton, and soybean and host trees in an adjacent woodline. We assessed parasitism and predation of naturally laid egg masses in crops and sentinel egg masses in host trees and used pheromone-baited traps to determine H. halys seasonal development. Overall, H. halys and N. viridula were the dominant bugs observed. Adult H. halys were first detected each year on trees, followed by corn, and then cotton and soybean, suggesting that trees served as a source of H. halys dispersing into crops. For H. halys , more nymphs were captured in soybean than in corn or cotton. For N. viridula , more adults were captured in corn and cotton than in soybean, and more nymphs were captured in corn during 2019 and 2021 than in 2020. Percentage parasitism of N. viridula egg masses (74.2%) was higher than than that for H. halys egg masses (54.3%). Accordingly, conservation biological control has the potential to enhance parasitism of indigenous stink bugs and H. halys in field crop agroecosystems. [ABSTRACT FROM AUTHOR]

Wheat is a globally important crop and one of the “big three” US field crops. But unlike the other two (maize and soybean), in the United States its development is commercially unattractive, and so its breeding takes place primarily in public universities. Troublingly, the incentive structures within these universities may be hindering genetic improvement just as climate change is complicating breeding efforts. “Business as usual” in the US public wheat-breeding infrastructure may not sustain productivity increases. To address this concern, we held a multidisciplinary conference in which researchers from 12 US (public) universities and one European university shared the current state of knowledge in their disciplines, aired concerns, and proposed initiatives that could facilitate maintaining genetic improvement of wheat in the face of climate change. We discovered that climate-change- oriented breeding efforts are currently considered too risky and/or costly for most university wheat breeders to undertake, leading to a relative lack of breeding efforts that focus on abiotic stressors such as drought and heat. We hypothesize that this risk/cost burden can be reduced through the development of appropriate germplasm, relevant screening mechanisms, consistent germplasm characterization, and innovative models predicting the performance of germplasm under projected future climate conditions. However, doing so will require coordinated, longer-term, inter-regional efforts to generate phenotype data, and the modification of incentive structures to consistently reward such efforts. [ABSTRACT FROM AUTHOR]

The adoption of a bioenergy crop is affected by various factors, including but not limited to the characteristics of farmers, farm economics, market forces, and physical environment. This study develops a spatially explicit agent‐based model for ascertaining the adoption rate of carinata (Brassica carinata) among the farmers in the Little River Experimental Watershed located in the southern state of Georgia in the United States. Each farmer's adoption behavior is modeled using the profitability difference between traditional crop rotations (with and without carinata at different contract prices), the adoption rate of neighboring farmers, and their land allocation decisions from managing a risky portfolio of enterprises. Carinata production in the winter season once every 3 years has no conflict with the most profitable and popular traditional row crop rotations, such as cotton‐cotton‐cotton and cotton‐cotton‐peanut, to a larger extent. The results show that 28% and 85% of farmers in the watershed will adopt carinata after 33 years at a contract price of $13/bushel (bu) under two different assumptions of low (2.5%) and high (5%) initial neighborhood adoption rates. The proportions of land allocated to carinata to the total farmland under field crops are 38% and 85% after 33 years under the same low and high neighborhood adoption rates, respectively. Our results suggest that fixing the appropriate contract price of carinata will bring additional profits to farmers without any significant foreseeable agronomic risks, thereby increasing the adoption rate of carinata at a regional level. [ABSTRACT FROM AUTHOR]

Autonomous equipment for crop production is on the brink of commercialization in the United States but federal, state, and local policies could affect commercial viability and hinder adoption. This article examines the farm‐level implications of both a speed restriction and on‐site supervisory regulations. The rules reduce the profitability of autonomous machinery, and for some scenarios autonomous machines are no longer an economically viable alternative to conventional machinery. Regulations also increase the optimal number autonomous machines required and influence production practices. Smaller farms have more flexibility in supporting the rules because they have more to gain from the use of autonomous equipment. Related Content: Lessons to be learned in adoption of autonomous equipment for field crops [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.) is one of the most extensively cultivated forage legumes in the world. It is currently the third most valuable field crop in the United States with an estimated value of over $9.3 billion. Alfalfa productivity is limited by various infectious diseases that can reduce forage yield and quality and shorten stand life. The crop can frequently be infected with a diverse array of pathogens and other organisms that have distinct life cycles, biology, and mode of action. Among them are many coinfecting viruses, that greatly contribute to the heterogeneity of within-host pathogenic communities, representing a ubiquitous and abundant background for all other host–pathogen interactions. Regrettably, the impact of viral diseases, their role in alfalfa health and involvement in the severity of multi-pathogen infections are often underestimated and not well understood. As high-throughput sequencing approaches have been developed, opportunities to delve into these complex interactions can be realized. In this work, we have characterized a diversity of viral populations in several commercial alfalfa production fields located in the U.S. Pacific Northwest. At least 45 distinct viruses have been identified in all alfalfa samples. Among them some were known to infect the crop prior to this study, and others were designated as emerging, novel and viruses integrated into the alfalfa genome. Known viruses included alfalfa mosaic virus, pea streak virus and bean leafroll virus, while among emerging and novel agents were alfalfa virus S, cherry virus Trakiya, several rhabdoviruses and others. Additional biological and impact studies will be needed to determine if newly identified viruses, especially those that have not been reported from alfalfa before, should be considered pathogens of this crop. [ABSTRACT FROM AUTHOR]

Sudden death syndrome (SDS), caused by Fusarium virguliforme , is an important yield-limiting disease of soybean ( Glycine max ). From 1996 to 2022, cumulative yield losses attributed to SDS in North America totaled over 25 million metric tons, which was valued at over US $7.8 billion. Seed treatments are widely used to manage SDS by reducing early season soybean root infection by F. virguliforme . Fluopyram (succinate dehydrogenase inhibitor [SDHI] - FRAC 7), a fungicide seed treatment for SDS management, has been registered for use on soybean in the United States since 2014. A baseline sensitivity study conducted in 2014 evaluated 130 F. virguliforme isolates collected from five states to fluopyram in a mycelial growth inhibition assay and reported a mean EC 50 of 3.35 mg/liter. This baseline study provided the foundation for the objectives of this research: to detect any statistically significant change in fluopyram sensitivity over time and geographical regions within the United States and to investigate sensitivity to the fungicide pydiflumetofen. We repeated fluopyram sensitivity testing on a panel of 80 historical F. virguliforme isolates collected from 2006 to 2013 (76 of which were used in the baseline study) and conducted testing on 123 contemporary isolates collected from 2016 to 2022 from 11 states. This study estimated a mean absolute EC 50 of 3.95 mg/liter in isolates collected from 2006 to 2013 and a mean absolute EC 50 of 4.19 mg/liter in those collected in 2016 to 2022. There was no significant change in fluopyram sensitivity ( P = 0.1) identified between the historical and contemporary isolates. A subset of 23 isolates, tested against pydiflumetofen under the same conditions, estimated an absolute mean EC 50 of 0.11 mg/liter. Moderate correlation was detected between fluopyram and pydiflumetofen sensitivity estimates ( R = 0.53; P < 0.001). These findings enable future fluopyram and pydiflumetofen resistance monitoring and inform current soybean SDS management strategies in a regional and national context., Competing Interests: The author(s) declare no conflict of interest.

Cover crops can positively impact productivity and the environment. While improved estimates of cover crop N benefits could help promote their adoption, little information is currently available at the broad scale. We conducted a multi-site study to determine whether use of satellite images and site factors could fill this gap. Six spectral indices were extracted from Sentinel-2 satellite imagery and used with modeling covariates to estimate cover crop properties and biomass N credits (biomass x N contents). The partial least squares regression (PLSR) models were calibrated and validated with samples from42 cover crop fields located in the midwestern and northeastern United States collected in 2017-2018. Remote sensing (RS)-derived spectral indices strongly correlated (r > .7) with red clover (Trifolium pratense L.) but not with rye (Secale cereale L.) biomass. Growing degree days (GDDs), cover height, ground cover percentage, and temperature often had high importance (variable importance in projection >1) in PLSR models. Model predictive power was limited for estimates of biomass N credits when data from all validation sites and cover types were used (adjusted [adj] R² = .52). However, models for both biomass (adj R² = .81) and biomass N credits (adj R² = .89) were successful for red clover fields. This suggests N benefits could be more effectively modeled for specific cover crop types. We also found RS-based estimation of C/N ratios performed moderately well when applied to the complete dataset (adj R² = .54), suggesting a way to differentiate grass and legume cover crops that can potentially inform biogeochemical models. [ABSTRACT FROM AUTHOR]

Volunteer corn arising from unharvested kernels in fields is a common problem that reduces yield of crops like soybean in intensive rotational agricultural systems. Over the last decade, farmers in the Midwestern United States have increased use of cover crops to improve soil health and suppress weeds in corn‐soybean rotational agriculture. We assessed whether the fate of unharvested corn kernels in cover‐cropped fields differed from fields without cover crops. After the 2018 harvest season, we recorded overwinter removal and spring 2019 germination of corn kernels from plots in six fields in Tippecanoe county, west‐central Indiana, United States. We used mixed effects logistic regression to model the role of a cereal rye cover crop, bare ground, soil drainage class, distance from field edge, and average height of vegetation on mortality of kernels. Probability of kernel absence from a plot was greater in fields planted to cover crops (0.93–0.98) than in no‐till fields without cover crops (0.53–0.85). Distance from field edge was positively related to kernel loss in cover‐cropped fields, but negatively related to loss in fields without cover crops. Within cover‐cropped fields, kernel removal near field edges increased to levels comparable to field interiors only for plots with >15% bare ground. Cover crops substantially reduced survival of corn kernels that serve as prospective volunteer corn, consistent with increased foraging activity and use of cover‐cropped fields by vertebrate seed predators. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.), also known as lucerne, is a major forage crop worldwide. In the United States, it has recently become the third most valuable field crop, with an estimated value of over $9.3 billion. Alfalfa is naturally infected by many different pathogens, including viruses, obligate parasites that reproduce only inside living host cells. Traditionally, viral infections of alfalfa have been considered by breeders, growers, producers and researchers to be diseases of limited importance, although they are widespread in all major cultivation areas. However, over the past few years, due to the rapid development of high-throughput sequencing (HTS), viral metagenomics, bioinformatics tools for interpreting massive amounts of HTS data and the increasing accessibility of public data repositories for transcriptomic discoveries, several emerging viruses of alfalfa with the potential to cause serious yield losses have been described. They include alfalfa leaf curl virus (family Geminiviridae), alfalfa dwarf virus (family Rhabdoviridae), alfalfa enamovirus 1 (family Luteoviridae), alfalfa virus S (family Alphaflexiviridae) and others. These discoveries have called into question the assumed low economic impact of viral diseases in alfalfa and further suggested their possible contribution to the severity of complex infections involving multiple pathogens. In this review, we will focus on viruses of alfalfa recently described in different laboratories on the basis of the above research methodologies. [ABSTRACT FROM AUTHOR]

Farmers, regulators, and researchers rely on pesticide use data to assess the effects of pesticides on crop yield, farm economics, off-target organisms, and human health. The publicly available pesticide use data in the United States do not currently account for pesticides applied as seed treatments. We find that seed treatment use has increased in major field crops over the last several decades but that there is a high degree of uncertainty about the extent of acreage planted with treated seeds, the amount of regional variability, and the use of certain active ingredients. One reason for this uncertainty is that farmers are less likely to know what pesticides are on their seed than they are about what pesticides are applied conventionally to their crops. This lack of information affects the quality and availability of seed treatment data and also farmers' ability to tailor pesticide use to production and environmental goals. [ABSTRACT FROM AUTHOR]

Organic agriculture promotes sustainability compared to conventional agriculture. However, the multifunctional sustainability benefits of organic farms might be mediated by landscape context. Assessing how landscape context affects sustainability may aid in targeting organic production to landscapes that promote high biodiversity, crop yields, and profitability. We addressed this using a meta-analysis spanning 60 crop types on six continents that assessed whether landscape context affected biodiversity, yield, and profitability of organic vs. conventional agroecosystems. We considered landscape metrics reflecting landscape composition (percent cropland), compositional heterogeneity (number and diversity of cover types), and configurational heterogeneity (spatial arrangement of cover types) across our study systems. Organic sites had greater biodiversity (34%) and profits (50%) than conventional sites, despite lower yields (18%). Biodiversity gains increased as average crop field size in the landscape increased, suggesting organic farms provide a "refuge" in intensive landscapes. In contrast, as crop field size increased, yield gaps between organic and conventional farms increased and profitability benefits of organic farming decreased. Profitability of organic systems, which we were only able to measure for studies conducted in the United States, varied across landscapes in conjunction with production costs and price premiums, suggesting socioeconomic factors mediated profitability. Our results show biodiversity benefits of organic farming respond differently to landscape context compared to yield and profitability benefits, suggesting these sustainability metrics are decoupled. More broadly, our results show that the ecological, but not the economic, sustainability benefits of organic agriculture are most pronounced in more intensive agricultural landscapes. [ABSTRACT FROM AUTHOR]

Bee diversity is declining in agricultural landscapes, altering pollination services that may support or enhance crop yields. Pollination services provided by wild bees are often limited to field margins adjacent to natural habitats, but methods to increase pollinators and their ecosystem services within field interiors remain elusive. Evidence is growing that wild bees enhance yields of flowering crops, including soybean (Glycine max (L.) Merrill). We tested responses of bee communities and soybean yield following pollinator exclosure and nesting manipulation experiments within production areas of the United States. We found that pollinator exclosures resulted in lower seed yield of soybean plants, and providing nesting substrate resulted in a yield increase as well as increases in ground-nesting bees. We provide evidence for soybean-associated bees and suggest these species may benefit from supplemental nesting substrate within production areas and increase soybean yields. [ABSTRACT FROM AUTHOR]

Focuses on the wheat production in the western United States. Introduction of wheat farming by the Europeans; Impact of wheat diseases on production; Classification of wheat diseases.

Organic farmers have identified soil fertility and weed management as the two highest research priority areas. No review exists of research on soil nutrient management in organic field crop systems. We conducted a comprehensive review to identify the principles and factors governing nutrient management, knowledge gaps, and future research needs in organic grain and other field crop systems in Canada and the United States. We compared results from research conducted in different climates, soils, and crop rotational sequences. Results indicate that (i) dual-use cover/ green manure crops and/or animal manure are the most common sources of plant available N and other nutrients in organic field crop systems; (ii) soil nutrient deficiencies can develop through sole reliance on cover/green manure crops; (iii) dependence on animal manure can lead to N and P excesses; (iv) conventional soil testing procedures may not accurately predict crop nutrient needs; (v) greater knowledge of microbial processes governing nutrient cycling is needed; and (vi) better understanding of the impact of weeds on soil fertility may create weed and nutrient management synergies. Knowledge gaps include a lack in understanding of how the soil and plant biomes influence nutrient-use efficiency and how crop diversity and rotations impact soil fertility, sustainability, and resilience in organic field crop systems. Likewise, interactions between weeds, crops, soil fertility, and weed management strategies are poorly understood. [ABSTRACT FROM AUTHOR]

Bumble bees are commonly used to provide pollination services within crop fields and greenhouses, with Bombus impatiens Cresson; Hymenoptera: Apidae, a bee native to the eastern United States, being the only managed bumble bee available commercially in the United States. Although many researchers have explored managed bumble bees' ability to pollinate various crops and the potential spread of pathogens by managed bumble bees, scant research is available on how managed bumble bee colony health is affected after foraging within crop fields. We measured 10 B. impatiens colony health parameters: 1) colony weight; number of 2) honey/pollen pots, 3) workers, 4) queens, 5) drones, 6) immatures, 7) eggs; and weight of 8) workers, 9) drones, and 10) queens from colonies that foraged within blueberry or watermelon fields, and compared them to control colonies that were purchased and immediately frozen upon receipt. Bees that foraged within blueberry increased in colony weight and in the number of immatures and eggs during the bloom period compared to control colonies. In contrast, bee colonies placed within watermelon decreased in colony weight, number of workers and immature bees, and individual bee weight compared to control colonies. Blueberry appeared to provide bees with sufficient nectar and pollen, whereas watermelon may not have provided adequate resources for the bees. Bees foraging within watermelon were probably forced to search for other sources of pollen and nectar, resulting in colony health parameter declines. Our data suggest that some crops (e.g. blueberry) can support managed B. impatiens , potentially adding to localized bumble bee populations, while others (e.g. watermelon) cannot. [ABSTRACT FROM AUTHOR]

Voles (Cricetidae) cause extensive damage to a variety of crops throughout much of the Northern Hemisphere. The removal of vegetation from crop fields at the end of the growing season, combined with a subsequent burrow fumigant application of aluminum phosphide, has the potential to substantially curtail vole activity but has not been thoroughly examined. We set up a study to test the impact of these management tools in perennial globe artichoke (Cynara cardunculus var. scolymus) fields in Monterey County, CA, during 2010 and 2011, to determine their potential utility as part of an integrated pest management (IPM) program for managing California voles (Microtus californicus). We used both chewing indices and mortality estimates derived via radiotelemetry to assess the efficacy of aboveground vegetation removal and aluminum phosphide applications on vole abundance. We determined the impact of plowing artichoke fields on vole activity as well. Both removal of vegetation and applications of aluminum phosphide substantially reduced vole presence within treated fields. Plowing also reduced vole abundance to the point of little residual activity following treatment. These management practices appear to be effective at eliminating voles from crop fields. Combining these tools with management practices designed to slow down reinvasion by neighboring vole populations (e.g., barriers, repellents, traps) has the potential to substantially reduce farmer reliance on rodenticides for vole management, although rodenticides will still be needed to curtail populations that reestablish within crop fields. Such an IPM approach should substantially benefit both farmers and agro-ecosystems. [ABSTRACT FROM AUTHOR]

Increased temperatures in the Southwestern USA will impact future crop production via multiple pathways. We used four methods to provide an illustrative analysis of midcentury temperature impacts to eight field crops. By midcentury, cropland area thermally suitable for maize cultivation is projected to decrease, while area suitable for cotton cultivation expands northward and nearly doubles in extent. The increase in area exposed to daily temperatures > 35 °C was highest for oat and maize. Estimates of yield reduction from heat stress for both maize and cotton indicate that historically, SW heat stress reduced cotton yield by 26% and maize yield by 18% compared to potential yield. By midcentury, we predict yield reduction from heat stress will reduce cotton and maize yields by 37 and 27%, respectively, compared to potential yield. Our results contradict the notion that the warmest counties cultivating field crops will be the most impacted. Rather, future temperature, total crop area and crop sensitivity contribute to more complex county-level impacts. Identification of representative target environments under future temperature regimes can inform development of farm-based networks to evaluate new crop germplasm with increased heat tolerance and viable adaptation and management strategies to respond effectively to future temperatures. [ABSTRACT FROM AUTHOR]

Crop intensification is a key aspect for achieving global food security and exploring options for optimizing land use and environmental resources. Following this rationale, a maize (Zea mays L.) – soybean (Glycine max L.) double cropping was tested to intensify current agricultural systems in the Southern region of the United States (US). The aims of this study were to i) assess the feasibility of cultivating maize-soybean double crop in the Southern US, ii) explore the best scenario of maize-soybean crops integrating field data with APSIM crop growth model via calculation of the land equivalent ratio (LER), and iii) evaluate the risk of crop failure for each crop combination. For this case study, one year field research and in-silico experiments using 30-years of weather data were analyzed to evaluate the different lengths of growth cycle for both crops for yield, LER, and percentage of success. The feasibility of the maize-soybean sequence was determined by increasing yield gain for the soybean crop while maintaining similar yield for maize crop. Simulated LER values ranged from 1.1 to 1.3 with the maize hybrid 110 comparative relative maturity followed by a soybean maturity group 3.0 as the best combination for maximum LER. Lastly, long-term simulations confirmed the low risk associated with maize-soybean double crop sequences across sowing dates. Expanding the implementation of this farming system could produce additional benefits not only on productivity and land use efficiency but in overall economic return for farmers in the Southern US region. [Display omitted] • Maize-soybean double cropping is a feasible production system in the Southern US. • Maximum land equivalent ratio was achieved with long-season maize with intermediate to long soybean maturity group. • Maize yield contribution to LER is a key factor for the overall maize-soybean system. • Soybean risk of not reaching maturity across sowing dates and maturities was low (<25%). [ABSTRACT FROM AUTHOR]

Seed treatments for the management of sudden death syndrome (SDS) caused by Fusarium virguliforme are available in the United States and Canada; however, side-by-side comparisons of these seed treatments are lacking. Sixteen field experiments were established in Illinois, Indiana, Iowa, Michigan, and Wisconsin, United States, and Ontario, Canada, in 2019 and 2020 to evaluate seed treatment combinations. Treatments included a nontreated check (NTC), fungicide and insecticide base seed treatments (base), fluopyram, base + fluopyram, base + saponin extracts from Chenopodium quinoa , base + fluopyram + heat-killed Burkholderia rinojenses , base + pydiflumetofen, base + thiabendazole + heat-killed B. rinojenses , and base + thiabendazole + C. quinoa extracts + heat-killed B. rinojenses . Treatments were tested on SDS moderately resistant and susceptible soybean cultivars at each location. Overall, NTC and base had the most root rot, most foliar disease index (FDX), and lowest yield. Base + fluopyram and base + pydiflumetofen were most effective for managing SDS. Moderately resistant cultivars reduced FDX in both years but visual root rot was greater on the moderately resistant than the susceptible cultivars in 2020. Yield response to cultivar was also inconsistent between the 2 years. In 2020, the susceptible cultivar provided significantly more yield than the moderately resistant cultivar. Treatment effect for root rot and FDX was similar in field and greenhouse evaluations. These results reinforce the need to include root rot evaluations in addition to foliar disease evaluations in the breeding process for resistance to F. virguliforme and highlights the importance of an integrated SDS management plan because not a single management tactic alone provides adequate control of the disease.

Petiole-NO 3 , leaf N and chlorophyll (SPAD) meter readings are good in-season indicators of the N status of the uppermost part of cotton ( Gossypium hirsutum L.) plants. Petiole-NO 3 , particularly is widely used in the USA as an in-season plant N test that guides N fertilizer recommendations in cotton. However, these N status indicators do not take account of plant biomass, canopy width or percent cover. The objectives of this study were to assess the effect of N fertilizer rates on the commonly used indicators of plant N status; leaf N, petiole sap NO 3 and chlorophyll meter (SPAD) readings and the plant growth measurements; plant height, canopy width, and percent ground cover, and determine to inter-correlations among the them. Irrigated field studies were conducted at Lubbock, TX USA in 2010 and 2011, New Deal, TX in 2010, and at Halfway, TX in 2011. Zero-N and a full N fertilizer rate of 134, 101, and 112 kg N ha −1 were used at Lubbock, New Deal, and Halfway, respectively. The 2010 cotton growing season in West Texas was much wetter than average, and the 2011 season was much drier than normal. As a result, plant height, canopy width, and ground cover were greater in the 2010 sites than in 2011. The effects of N fertilizer were greatest for the two cultivars in subsurface drip irrigation (SDI) at New Deal in 2010 for all three N status indicators, and for the three plant growth measures compared to the other site-years. Correlation analysis indicated that among the three plant N indicators, leaf N was the most sensitive to plant parameters. These effects were positive in 2010 and negative in the 2011 dry year. Petiole NO 3 was the plant N indicator that was the most insensitive to plant growth, but the marked seasonal decline pattern reduces its usefulness for late-season N management. [ABSTRACT FROM AUTHOR]

Genetically diverse germplasm is needed to increase frequency of favorable alleles of economically important traits in maize improvement. The objectives of this study were to determine the genetic components involved in grain yield and grain quality traits, and provide preliminary assessment of useful heterotic groups and patterns from a large sample of maize populations adapted to the northern U.S. Corn Belt. Sixteen populations were used in the diallel mating design following Gardner-Eberhart Analysis II to estimate variety ( v) and heterosis ( h) genetic effects for grain yield and grain quality traits. Specific heterosis ( s) and predicted means of population crosses for grain yield were used to evaluate the heterotic relationships among the populations. Data for grain yield and grain quality traits were generated in partially balanced single lattice experiments across North Dakota (ND) locations in 2010, 2011, and 2012. Analyses of variance showed significant differences among genotypes. Heterosis effects explained most of the differences among diallel entries for grain yield, while v effects had greater influence on grain quality traits. NDL, EARLYGEM 21c, NDSCD(FS-CS)C2, NDSS, and NDSM(M-FS)C9 were identified as elite populations for grain quality improvement. NDSS × NDBS22(R-T1)C9 and NDBS1011 × EARLYGEM 21c showed high s effects for grain yield with good grain quality. NDSS and EARLYGEM 21c represent stiff stalk synthetic (SSS) group, and NDBS1011 fall under non-SSS group. Further studies need to validate the heterotic group of NDBS22(R-T1)C9. Recurrent and pedigree selection programs will be established for selected populations and population crosses to integrate pre-breeding with cultivar development. [ABSTRACT FROM AUTHOR]

Summary: Application of two-step approach of evapotranspiration (ET) crop coefficients (Kc) to “approximate” a very complex process of actual evapotranspiration (ETa) for field crops has been practiced by water management community. However, the use of Kc, and in particular the concept of growing degree days (GDD) to estimate Kc, have not been sufficiently studied for estimation of evaporative losses from riparian vegetation. Our study is one of the first to develop evapotranspiration crop coefficient (KcET ) curves for mixed riparian vegetation and transpiration (TRP) crop coefficients (KcTRP ) for individual riparian species as a function GDD through extensive field campaigns conducted in 2009 and 2010 in the Platte River Basin in central Nebraska, USA. KcTRP values for individual riparian vegetation species [Common reed (Phragmites australis), Cottonwood (Populus deltoids) and Peach-leaf willow (Salix amygdaloides)] were quantified from the TRP rates obtained using scaled-up canopy resistance from measured leaf-level stomatal resistance and reference evapotranspiration. The KcET and KcTRP curves were developed for alfalfa-reference (KcrET and KcrTRP ) surface. The seasonal average mixed riparian plant community KcrET was 0.89 in 2009 and 1.27 in 2010. In 2009, the seasonal average KcrTRP values for Common reed, Cottonwood and Peach-leaf willow were 0.57, 0.51 and 0.62, respectively. In 2010, the seasonal average KcrTRP were 0.69, 0.62 and 0.83 for the same species, respectively. In general, TRP crop coefficients had less interannual variability than the KcrET . Response of the vegetation to flooding in 2010 played an important role on the interannual variability of KcrET values. We demonstrated good performance and reliability of developed GDD-based KcrTRP curves by using the curves developed for 2009 to predict TRP rates of individual species in 2010. Using the KcrTRP curves developed during the 2009 season, we were able to predict the TRP rates for Common reed, Cottonwood and Peach-leaf willow in 2010 within 7%, 8% and 13% accuracy, indicating a good performance of the two-step approach proposed in this study for estimating TRP for riparian vegetation. The surface conditions of the riparian ecosystem need to be considered when using the two-step approach to estimate ETa or TRP rates of riparian plant communities. The results of this study provide important water use information and data for riparian vegetation that can be used for more robust hydrologic/water balance analyses. [Copyright &y& Elsevier]

Collections of wheat leaves infected with the leaf rust fungus, Puccinia triticina , were obtained from the southeastern states, the Ohio Valley, the Great Plains, and Washington in 2018, 2019, and 2020 to determine the prevalent virulence phenotypes in the wheat-growing regions of the United States. In the hard red winter wheat region of the southern and mid Great Plains, MNPSD and MPPSD were the two most common phenotypes in 2018 and 2019. In 2020, BBBQD with high virulence to durum wheat was the most common phenotype in the southern Great Plains. In the hard red spring wheat region of the northern Great Plains, MNPSD, MPPSD, MBDSD, and TBBGS were the predominant phenotypes. In the soft red winter wheat region of the southeastern states and Ohio Valley region, MBTNB, MCTNB, and MNPSD were the three most common phenotypes. Collections in Washington had phenotypes LBDSG, LCDSG, LCDJG, and MBDSB that were not found in any other region. Isolates with virulence to the leaf rust resistance ( Lr ) gene Lr11 were most frequent in the southeastern states and Ohio Valley regions. The frequency of isolates with virulence to the Lr39 gene was highest in the Great Plains region and frequency of isolates with virulence to the Lr21 gene was highest in the northern Great Plains region. Selection of virulence phenotypes by Lr genes in the different market classes of wheat, combined with the effects of clonal reproduction, overwintering in southern regions, and low migration between the Great Plains region and eastern wheat-producing regions, has maintained the different P . triticina populations in the United States.

We estimate the factors determining specialization of crop choice at the level of individual fields, distinguishing between the role of natural advantage (soil characteristics) and economies of density (scale economies achieved when farmers plant neighboring fields the same). Using rich geographic data from North Dakota, including new data on crop choice collected by satellite, we estimate a model of how a farmer plants adjacent fields under the farmer's control. We find planting decisions on a field are heavily dependent on the soil characteristics of adjacent fields. Through this relationship, we back out the structural parameters of economies of density. [ABSTRACT FROM AUTHOR]

This study examines the suitability of 250 m MODIS (MODerate Resolution Imaging Spectroradiometer) data for mapping global cropland extent. A set of 39 multi-year MODIS metrics incorporating four MODIS land bands, NDVI (Normalized Difference Vegetation Index) and thermal data was employed to depict cropland phenology over the study period. Sub-pixel training datasets were used to generate a set of global classification tree models using a bagging methodology, resulting in a global per-pixel cropland probability layer. This product was subsequently thresholded to create a discrete cropland/non-cropland indicator map using data from the USDA-FAS (Foreign Agricultural Service) Production, Supply and Distribution (PSD) database describing per-country acreage of production field crops. Five global land cover products, four of which attempted to map croplands in the context of multiclass land cover classifications, were subsequently used to perform regional evaluations of the global MODIS cropland extent map. The global probability layer was further examined with reference to four principle global food crops: corn, soybeans, wheat and rice. Overall results indicate that the MODIS layer best depicts regions of intensive broadleaf crop production (corn and soybean), both in correspondence with existing maps and in associated high probability matching thresholds. Probability thresholds for wheat-growing regions were lower, while areas of rice production had the lowest associated confidence. Regions absent of agricultural intensification, such as Africa, are poorly characterized regardless of crop type. The results reflect the value of MODIS as a generic global cropland indicator for intensive agriculture production regions, but with little sensitivity in areas of low agricultural intensification. Variability in mapping accuracies between areas dominated by different crop types also points to the desirability of a crop-specific approach rather than attempting to map croplands in aggregate. [ABSTRACT FROM AUTHOR]

Abstract: Saflufenacil is a new herbicide being developed for pre-plant burndown and pre-emergence broadleaf weed control in field crops, including maize, soybean, sorghum and wheat. Field experiments were conducted in 2007 and 2008 in northeast Nebraska, USA to describe dose-response curves of saflufenacil applied in mid (early post-emergence, EPOST) and late May (late post-emergence, LPOST) with several adjuvants for spring emerging broadleaf weed control. Dose-response curves based on log-logistic model were utilized to determine the ED90 values (effective dose that provides 90% weed control efficacy) for Convolvulus arvensis, Lactuca serriola, Lamium amplexicaule, Capsella bursa-pastoris, Taraxacum officinale, Thlaspi arvense and Conyza canadensis. In general, weed control efficacy was influenced by application timing and type of adjuvant. EPOST application of saflufenacil resulted better efficacy of saflufenacil compared to LPOST. Addition of spray adjuvants improved efficacy of saflufenacil. For example, 90% control of T. arvense was obtained at EPOST application with 251, 161, 96 and 59ga.i.ha−1 for saflufenacil applied alone, or tank-mixed with NIS (nonionic surfactant), COC (crop oil concentrate), or MSO (methylated seed oil), respectively. In contrast, the ED90 values with LPOST application were 333, 201, 127 and 79ga.i.ha−1 for saflufenacil applied alone, or with NIS, COC and MSO, respectively. MSO was the best adjuvant, which provided the most enhancement of saflufenacil. COC was the second best, or similar to MSO, on many weed species. NIS provided the least enhancement of saflufenacil. The ED90 values determined for different broadleaf weed species are within the proposed label dose of saflufenacil. [Copyright &y& Elsevier]

Abstract: We used an object-oriented approach in conjunction with the Random Forest algorithm to classify agricultural practices, including tillage (till or no-till (NT)), crop intensity, and grassland-based conservation reserve (CR). The object-oriented approach allowed for per-field classifications and the incorporation of contextual elements in addition to spectral features. Random Forest is a classification tree-based advanced classifier that avoids data over-fitting associated with many tree-based models and incorporates an unbiased internal classification accuracy assessment. Landsat satellite imagery was chosen for its continuous coverage, cost effectiveness, and image accessibility. Classification results for 2007 included producer''s accuracies of 91% for NT and 31% for tillage when applying Random Forest to image objects generated from a May Landsat image. Low classification accuracies likely were attributed to the misclassification of conservation-based tillage practices as NT. Results showed that the binary separation of tillage from NT management is likely not appropriate due to surface spectral and textural similarities between NT and conservation-type tillage practices. Crop and CR lands resulted in producer''s accuracies of 100% and 90%, respectively. Crop and fallow producer''s accuracies were 95% and 82% in the 2007 classification, despite post-senesced vegetation; misclassification within the fallow class was attributed to pixel-mixing problems in areas of narrow (<100 m) strip management. A between-date normalized difference vegetation index approach was successfully used to detect areas having “changed” in vegetation status between the 2007 and prior image dates; classified “changed” objects were then merged with “unchanged” objects to produce crop status maps. Field crop intensity was then determined from the multi-year analysis of generated crop status maps. [Copyright &y& Elsevier]

Soybean [Glycine max (L.) Merrill] is a major crop in the world and in the United States. In 2006, soybeans represented 57% of the world oilseed production. Because of oxidation problems upon heating and storage of the oil, and because of health risks related to the production of trans-fatty acids during oil hydrogenation, reducing linolenic acid content in soybean oil below 2% is now an important goal in soybean breeding programs. The current methods for evaluation of the fatty acid content in the oil (fat extraction and gas chromatography-mass spectrometry analysis of the fatty acids) are time consuming and expensive. Our objective was to develop molecular markers that would allow the selection for low linolenic acid lines without the need for analysis of the fatty acid content of the oil. Populations were developed by crossing a low linolenic parent with highyielding adapted South Dakota lines. We developed a molecular marker that was linked to the low linolenic acid trait in our populations and permitted effective selection for low linolenic acid lines. In the three populations developed for the study, a single backcross proved to be the most effective way to combine the low linolenic acid trait of the donor parent with the high-yielding genes of the recurrent parent. [ABSTRACT FROM AUTHOR]

The United States is a large country with a diversity of forage ecosystems and forage species to fill the varied management options within each ecosystem. For example, the American Seed Trade estimates seed of 5,500 varieties representing 1,500 grass and 4,000 legume species are produced annually. The economic benefits of forage improvement are both direct (seed and hay sales) and indirect (saleable animal products, nitrogen fixation and conservation uses). The benefits of improving forages through breeding are likewise important due to the current use of improved varieties to underpin these systems and their direct and indirect products. Because of the diversity of species and management systems, only a few case studies were examined in this paper to estimate these benefits. These were the alfalfa ( Medicago sativa L.) industry (economic value of US$8.1 billion per year), the forage and livestock systems of the southeastern USA (economic value estimated overall at US$11.4 billion per year), and switchgrass ( Panicum virgatum L.) and its potential use as bio-energy feedstock (economic value of needing an additional 28 million acres of production to supply the estimated future feedstock needs). The overall conclusion is that the economic benefits from forage improvement in the USA have been, and continue to be, immense. However, future resources are going to fewer crops, and these crops are the ones that have greater economic value and where biotechnology can be applied. This will favor alfalfa and penalize forage grasses. Even for crops with an identifiable path to market, this concentration of resources in fewer hands requires development of consortia where organizations can leverage their resources with others who possess complementary resources. The Consortium for Alfalfa Improvement is a good example of how this could work. [ABSTRACT FROM AUTHOR]

This study investigates the role of risk in farmers' acreage decisions for major field crops in the North Central region by revisiting an earlier study by Chavas and Holt. The empirical model is forward-looking and reflects better variable measurement. We test the effects of wealth and revenue risk on supply response. Estimated results are also used to examine the production impact of counter-cyclical payments (CCPs). We find that the effects of risk on supply response are not strong. An increase in initial wealth would lead to greater crop acreage, consistent with decreasing absolute risk aversion. The effect of CCPs on production appears to be negligible. [ABSTRACT FROM AUTHOR]

The soybean aphid, Aphis glycines Matsumura, is a newly invasive species of aphid in North America. Previous studies disagree as to whether soybean, Glycine max (L.) Merr., plant stage has an impact on aphid intrinsic rate of increase. Therefore, the growth rate of soybean aphids on soybean plants of different stages was examined at two different scales in the field. A planting date experiment was used to measure the population growth of soybean aphids on plants of different stages. Clip-cages were used to measure life history characteristics of individual aphids on plants of different stages. No differences were found in the population growth or dynamics of soybean aphids in the planting date experiment. The life history characteristics of individual aphids also showed no significant difference when feeding on different growth stages of soybean plants. The impact of these findings on soybean aphid management is discussed and the possible reasons why the results differ from previous estimates of the aphid growth-plant stage relationship are considered. [ABSTRACT FROM AUTHOR]

Field experiments were conducted to determine the possibility of growing cowpea as an alternative crop in the cropping system of the Delaware, Maryland and Virginia (Delmarva) region of the United States. Cowpea genotypes were grown for two seasons and the parameters evaluated mostly included grain yield, biological yield, flowering and maturity dates. Results showed significant differences in grain and biological yields of various genotypes. Genotypes Colossus, Mississippi Silver and California Blackeye 5 gave significantly higher seed yields. The highest biological yield was provided by genotypes Champion, White Acre and California Blackeye 5 making these genotypes good candidates to be used for green manuring or as cover crops in the region. Genotypes Quickpick Pinkeye and Elite were found to be early maturing and might escape the terminal drought. Soils in the Delmarva region are sandy, prone to drought but support corn and soybean which are the major crops in the region. The results indicate that introduction of cowpea in the Delmarva region could play an important role in replacing some of the areas currently being used for corn and soybean production, an important source of vegetable proteins to many ethnic groups in the area, play an important role as an alternative crop, improve soil fertility to sustain crop production, and also to serve as an insurance crop, especially during drought years in the Delmarva region. [ABSTRACT FROM AUTHOR]

Focuses on the origins and historical background of the Maize Genetics Cooperation in the U.S. Definitive correlation of chromosomes and linkage groups in maize; Proponents for the expanded networks of maize research; Contributions of maize genetics school to the progress of corn breeding and to general knowledge in genetics.

By introgressing exotic germplasm into elite maize in the USA, breeders have developed lines with wider variability for seed oil and protein contents than in U.S. adapted lines. Seed quality of these introgressed lines has not been evaluated. The objectives of the study were (i) to characterize introgressed inbred lines for seed quality, (ii) to assess the effects of oil and protein contents on seed quality, and (iii) to determine whether the interaction between genetic background and production location was significant. The lines used in the study were developed by crossing elite lines of Stiff Stalk and non-Stiff Stalk heterotic background with St. Croix and Argentina germplasm. They were grown at four locations of the U.S. Corn Belt. Seed quality was measured by standard germination test, a series of vigor tests, and an inbred quality index. Genotype × location interactions were significant. Genotypic differences were observed for all the traits measured within each location. Seed composition and genetic background did not affect germination, however production location did. Standard germination ranged from 56 to 93% in Iowa, 48 to 89% in Missouri, 53 to 91% in Illinois, and 52 to 89% in Nebraska. High protein inbred lines had a saturated cold test of 64%, averaged across locations, while the low protein line averaged 49%. Inbred lines with St. Croix background and lines produced in colder locations (Iowa and Nebraska) had high cold test percentage. Inbred lines with St. Croix background, all having Iow oil contents, had the lowest accelerated aging test results (49%), whereas inbred lines with Argentina background had the highest (65%). The Iow protein inbred line had low accelerated aging results (49%), whereas high protein inbred lines averaged 62%. Because seed composition affects seed quality of the inbred, it is important that breeders evaluate new germplasm for seed quality early in the breeding program. [ABSTRACT FROM AUTHOR]

Reports on the attack of cotton in the U.S. by plant-parasitic nematodes. Recognition of the importance of the fiber crop to the U.S. economy; Increase of the dependence of cotton cultivation on chemical pesticides for weed and pest control; Use of transgenic cultivars to increase cotton production; Consideration of the damage by nematodes to cotton since the late 19th century; Discussion different types of nematodes.

Nontarget arthropod populations were monitored in both transgenic and nontransgenic corn and soybean fields in western and central Ohio. A total of 24 fields, 12 eom and 12 soybean, were inspected weekly from late June through mid August. Half of the cornfields were Bacillus thuringiensis (Bt) hybrids and half of the soybean fields were Roundup Beady (BB). Sweep net samples in soybean fields and unbaited Pheroeon AM yellow sticky traps in both soybean and cornfields were used to collect nontarget arthropods. Soil samples were also taken from all 24 fields to compare soil mite populations. A select group of 15 readily identifiable arthropods composed mainly of beneficial insects commonly found in field crops, were recorded in weekly sweep net and sticky trap samples for later analysis. Sweep net data from soybean fields revealed no significant differences in nontarget arthropods. Yellow sticky trap data from soybean and eom fields found significantly more green lacewing adults (Chrysopa spp.) in six pooled non-RR soybean fields, significantly more rove beetles in one non-Bt cornfield, and significantly more Orius spp. in one Bt cornfield. There were also significantly more soil inhabiting mites at one non-RR soybean field. Based on the abundance of these arthropod populations in paired transgenic and nontransgenic fields, few negative effects on the 15 nontarget arthropods selected can be directly associated with transgenic soybean and corn crops in Ohio. [ABSTRACT FROM AUTHOR]

Focuses on the salt tolerance of the field crops in saline media in the United States. Increase production of biomass and grain in wheat crop; Reduction of the durum wheat; Identification of the root-zone salinity levels.

Forage crops and soil attributes were evaluated for 4 years at three sites in Alaska. Annual herbage yields usually exceeded 5 Mg ha[sup -1] on neutral soils at Fairbanks (64°52' W) and on moderately acidic soils at Point MacKenzie (61°24' N, 150°3' W). Strongly acidic, droughty soils at Delta Junction (63°55' N, 145°20' W) produced low yields for all crops. Soil pH decreased significantly over 4 years under N-fertilized grasses at Delta Junction and under alfalfa and N-fertilized barley at Fairbanks. Soil organic C and N and microbial biomass C showed no differences among treatments at the end of the study. Wet aggregate stability did not vary significantly among crops but was lower for fallow. The results of this study indicated a high potential for use of perennial forage legumes at some locations in Alaska. The lack of large differences in most soil parameters indicates slow responsiveness to management by some commonly used soilquality indicators under subarctic conditions. [ABSTRACT FROM AUTHOR]

Compares several field crops in the western United States. Role of plant breeding in plant growth cycle and type; Effect of crop morphology and phenology on productivity; Origin of rice and sorghum.

[Display omitted] • This study examined how pesticides influence beneficial biota in field crops. • Pesticidal seed treatments and sprays decreased total predator activity-density. • In year one, seed treatments and sprays decreased spider activity-densities. • In year three, spider activity-density increased with seed treatments alone. • Overall, the use of pesticides did not improve crop yield in maize or soybean. Field crop growers in the United States have adopted prophylactic pest management strategies to control sporadic crop pests that are spatially and temporally difficult to predict. While evidence shows these preventative management practices, specifically pesticidal seed treatments, can be important in regions with predictable pest pressures, employing them ubiquitously in field crops across the northeastern U.S. can have variable returns on productivity. Further, prophylactics may also limit the potential of integrated pest management (IPM). A three-year field experiment (2017–2019) was conducted in a maize-soybean cropping system to compare the influence of a preventative pest management practice and a scouting-based IPM practice on biological control organisms. Aboveground predator densities were measured via pitfall trapping and predation temporal dynamics were assessed using a standard sentinel-bait assay at two time points per year. Belowground biological control potential was determined using a sentinel-bait bioassay to quantify the abundance of soil-borne entomopathogenic fungi (EPF). The variable responses of beneficial communities to pesticide inputs were strongly influenced by season and time of application, underscoring the importance of applying pesticides only when necessary. Compared with no pesticide use, pesticidal seed treatments and foliar sprays together in a maize-soybean production system suppressed total predator activity-density, spider activity-density, predation, and infection potential of soil-borne entomopathogenic fungi in one out of three years of the field study. In the third year, the activity-density of spiders increased across all fields in preventative plots that included seed treatments only. Overall, the use of pesticides did not improve crop yield in either maize or soybean. These findings highlight that the use of a prophylactic pesticide program may not always be necessary for maximum crop productivity and that this management approach can occasionally have unintended negative consequences on above- and belowground soil biota and the ecosystem services they provide. [ABSTRACT FROM AUTHOR]

We apply a Bayesian framework in which the adequacy of natural science information used in setting environmental regulations may be assessed. Informational adequacy is defined as the extent to which the variability in agricultural yield response information affects the probabilities of overestimating ultimately realized economic surplus and thereby failing to plan for a more lax ambient pollution standard, or by underestimating the realized surplus and thereby failing to plan for a stricter ambient standard. For linear and for quadratic yield response functions, the framework is applied to four major U.S. field crops having dissimilar growing requirements and diverse market relations. [ABSTRACT FROM AUTHOR]

An empirical analysis of risk sensitivity of supply response is attempted here for seven major field crops in California over a twenty-two year period 1949-70. Two distinct types of risk sensitivity are evidenced by the empirical trend e.g., for crops like alfalfa, sugarbeets and sorghum, where short run adjustment factors are important, the year-to-year acreage changes reflect the negative impact of price and returns risk very strongly. For other crops like rice and barley, where long run factors of adjustment are important, the impact of price changes rather than the variance of prices or returns are more important. This pattern of risk sensitivity has important economic implications for welfare gains resulting from price support and stabilization policies pursued by the federal government. [ABSTRACT FROM AUTHOR]

The impact of risk aversion on supply response is empirically estimated for selected field crops in California. As indicators of risk aversion the following surrogate variables are used: variance of past prices and yields, adjusted price to reflect the role of government support price over' the market price and the dummy variables indicating price expectations. In general, the econometric estimates show a negative impact of risk aversion measured by the surrogate variables and this has implications for welfare gains resulting from price support policies aimed at stabilization. [ABSTRACT FROM AUTHOR]

This paper considers the role of competitive storage in markets for annually harvested field crops. A quarterly model is presented that considers the allocative role of storage both within and between crop years. Rational price expectations are endogenous variables calculated by a recursive method. Forward stochastic simulations using the model generate data that can be used to characterize the distributions of the variables. In the base case, the model is assigned parameter values from a quarterly econometric model of the U.S. soybean market. The results shed light on the distributions of the quarterly variables, including the rational price expectations, and show how these distributions are affected by changes In the carrying charge. [ABSTRACT FROM AUTHOR]