Agronomy Journal最新文献

Growth in demand for organic small grains has increased interest in producing certified organic crops in the semiarid US Pacific Northwest. The region is well-suited for small grain production, and there is a strong market for organic food products on the US West Coast. However, many growers encounter significant and persistent challenges with weed management, particularly management of perennial weeds such as Canada thistle [Cirsium arvense (L.) Scop.] and field bindweed (Convolvulus arvensis L.), but also common winter and spring annual grass weeds including cheatgrass (Bromus tectorum L.) and wild oat (Avena fatua L.). Coupled with the need to minimize soil disturbance, weed management can become nearly intractable and production limiting. From 2004 to 2024, several short and intermediate studies have been conducted to assess weed control tactics and crop rotation effects on weed management. Lessons learned include incorporating alfalfa (Medicago sativa L.) and spring barley (Hordeum vulgare L.) into rotations for suppression of field bindweed, or alfalfa and winter triticale (x Triticosecale Wittmack) for suppression of Canada thistle. Optimization of cultural inputs, particularly seeding rate, are critical for each crop in rotation. Animal integration and new crops such as quinoa (Chenopodium quinoa Willd.) are alternatives to conventional crops and potentially profitable. Incorporation of precision mechanical and chemical systems is feasible in narrow-row cereals, and when combined with crop rotation, it could reduce or eliminate the need for repeated transitions back to convention production for organic growers.

The effectiveness of frequent compost application in improving soil health is well-documented. Less is known on the long-term effects of infrequent compost application to semiarid soils. Compost made of dairy manure and straw bedding was applied once in a dryland organic hard red winter wheat (Triticum aestivum L. emend. Thell.)–fallow system at 50 Mg ha⁻¹ dry wt. in 1994 in a randomized complete block design with three replicates. Twenty-eight years later, yields in composted plots (1.4 Mg ha⁻¹) remained higher (p < 0.1) than in control plots (0.79 Mg ha⁻¹). Plant-available P, acid phosphatase activity (ACP), and total N were higher in composted plots by 143%, 37%, and 29%. Soil organic carbon (SOC) and dehydrogenase enzyme activity were greater by 25% and 20% with compost compared to the control, as were aggregate stability determined using SLAKES method, autoclave-extractable protein, and CO₂-96 h by 143%, 22%, and 16%. Soil extractable K and Zn also increased with compost application. The interaction of ACP and estimated evapotranspiration (ET) emerged as a pivotal factor in explaining the variation in yield. These findings suggest that growers may see some yield improvements from periodic compost applications to dryland organic winter wheat–fallow systems. This strategy could help rebuild SOC and partially counter the challenges of low and variable precipitation.

Though corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] are widely grown and readily accepted into commodity markets and biofuel facilities, heavy reliance on seeds of those two crops for bioenergy production has been linked to environmental degradation, including nutrient discharge to water, and to constraints on food production. Alternative biofuel feedstock systems might better address this “food–energy–environment trilemma.” Using data from a 9-ha field experiment in Iowa, we evaluated yields from a 14-year period for four bioenergy feedstock systems: stover harvested from corn grown with and without an unharvested rye cover crop, and prairie vegetation grown with and without fertilizer. We also assessed sub-surface drainage flows and NO₃-N concentrations and discharges in leachate from those cropping systems. The continuous corn systems produced mean grain yields of 11.0–11.5 Mg ha⁻¹ year⁻¹, while also yielding about 4 Mg ha⁻¹ year⁻¹ of stover. Mean harvested biomass from the fertilized prairie was 83% greater than from the unfertilized prairie and was superior to stover production in the two corn treatments in 11 out of 14 years. Nitrate-N losses in drainage water from the corn systems averaged 12–14 kg NO₃-N ha⁻¹ year⁻¹, whereas both the fertilized and unfertilized prairie systems almost eliminated NO₃-N loss. Cover cropping with rye reduced NO₃-N loss in only one out of 13 years and had variable effects on corn yield. Adoption of prairie-based biofuel systems might be driven by placing perennial feedstocks on environmentally sensitive sub-field areas and by government policies that favor perennial feedstocks over annual crops like corn.

Rotational benefit of pea (Pisum sativum L.) may reduce N fertilization rate and sustain malt barley (Hordeum vulgare L.) yield and quality in the malt barley-pea rotation. This study examined the effect of cover crop [oat (Avena sativa L.) cover crop vs. none] and N fertilization rate (0, 40, 50, 60, 70, and 80 kg N ha⁻¹) on malt barley growth, yield, and quality in the malt barley-pea rotation from 2012 to 2019 in the northern Great Plains. Cover crop biomass yield and N accumulation were greater in 2016 than other years. Compared to fallow, malt barley plant density with cover crop was 9%–13% lower from 2013 to 2015, but 10% greater in 2017. Malt barley straw yield was 38% greater in 2017 and grain yield 15%–39% greater in 2017 and 2018, but grain plumpness was 5%–10% lower in 2014 and 2017 with than without cover crop. Increasing N fertilization rate linearly increased grain yield and N uptake, but reduced grain test weight and plumpness in most years. Straw N concentration and uptake and grain protein concentration varied by year. Because of the similar grain yield, protein concentration, plumpness, and test weight between 60 and 80 kg N ha⁻¹, 60 kg N ha⁻¹ can be recommended to sustain malt barley yield and quality in the malt barley-pea rotation, regardless of cover crops. This helps to reduce N fertilization rate by 20 kg N ha⁻¹ for malt barley in dryland cropping systems of the US northern Great Plains.

This study investigated the impact of biochar on Zea mays L. yield and greenhouse gas (GHG) emissions in rainfed maize fields in Northwest China. Four treatments were compared: unmodified control (CK), conventional nitrogen (BC0), nitrogen + 20 t ha⁻¹ biochar (BC20), and nitrogen + 50 t ha⁻¹ biochar (BC50). Results showed significant increases in grain yields with BC20 (11.1%) and BC50 (8.6%) compared to BC0. Emissions of nitrous oxide (N₂O) were reduced by 14.0%–19.5% in biochar treatments compared to CK. Methane (CH₄) uptake by the fields, acting as CH₄ sinks, was not significantly impacted by biochar treatments, clarifying that the biochar did not alter the farmland's inherent ability to uptake CH₄. Over 2 years, the addition of nitrogen fertilizer and biochar did not markedly alter cumulative CH₄ uptake. Both net greenhouse gas (NGHG) emissions and yield-scaled GHG intensity (NGHGI) were lowered by 16.7%–23.5% and 24.2%–30.3%, respectively, with biochar application. The integration of biochar effectively mitigated the GHG emission enhancement due to nitrogen fertilizer, mainly by decreasing nitrogen oxide emissions and boosting maize yields. Thus, proper biochar application would be an economical and effective strategy for mitigating gas emissions from rainfed maize cropping system in semiarid regions.

Long-term agricultural field experiments (LTFEs) have been conducted for nearly 150 years. Yet lack of coordination means that synthesis across such experiments remains rare, constituting a missed opportunity for deriving general principles of agroecosystem structure and function. Here, we introduce the Diverse Rotations Improve Valuable Ecosystem Services (DRIVES) project, which uses legacy data from North American LTFEs to address research questions about the multifunctionality of agriculture. The DRIVES Project is a network of researchers who have compiled a database of primary (i.e., observations) and secondary (i.e., transformed observations or modeling results) data from participating sites. It comprises 21 LTFEs that evaluate how crop rotational diversity impacts cropping system performance. The Network consists of United States Department of Agriculture, university, and International Maize and Wheat Improvement Center scientists (20 people) who manage and collect primary data from LTFEs and a core team (nine people) who organize the network, curate network data, and synthesize cross-network findings. As of 2024, the DRIVES Project database contains 495 site-years of crop yields, daily weather, soil analysis, and management information. The DRIVES database is findable, accessible, interoperable, and reusable, which allows integration with other public datasets. Initial research has focused on how rotational diversity impacts resilience in the face of adverse weather, nutritional quality, and economic feasibility. Our collaborative approach in handling LTFE data has established a model for data organization that facilitates broader synthesis studies. We openly invite other sites to join the DRIVES network and share their data.

The number of experiments to be used in path analysis to enhance the efficacy of indirect selection for fast-cooking common bean (Phaseolus vulgaris L.) lines has not yet been defined. This study sought to break down the correlation coefficient into direct and indirect effects for quality traits and mineral concentration based on data acquired from multi-environment experiments. Additionally, the study proposed to establish the minimum number of experiments required for path analysis aiming at indirect selection for fast cooking in common bean. Four experiments were conducted in which various quality traits and the concentration of seven minerals were analyzed across 25 common bean cultivars. Variance and path analyses were applied to data from individual experiments and combinations of two, three, and four experiments. Significant cultivar × experiment interaction effects were found for most evaluated traits. The traits exerting the greatest direct effects on cooking time varied across the four experiments. Data from individual experiments were highly variable, resulting in low ability to identify promising traits for indirect selection. However, data from two, three, and four experiments had lower variability and therefore provided a greater ability to identify traits with the greatest direct and indirect effects on cooking time. Mass of 100 grains and calcium concentration emerged as promising traits for indirect selection to achieve fast cooking in common bean. Using data from two experiments allows for an effective interpretation of path analysis results for quality traits and mineral concentration in common bean.

Sunflower (Helianthus annuus) is a widely cultivated crop that exhibits a trait known as capitulum (or head) inclination at maturity. This trait is influenced by various structural factors, including head weight, stem traits, and plant height. A sunflower head should be at an angle at which the head faces the ground to avoid damage from the sun and birds. While this desired inclination range is known, current methods, including visual estimation and a model of measuring inclined length of the stem, fail to provide precise measurements of angle. This study introduces novel approaches to mathematically measure the head inclination angle. The research, which was conducted over the 2022 and 2023 growing seasons, involved an aluminum rod equipped with a ruler and a digital protractor to measure various height and angle components. Using the data collected, three methods were applied for measuring inclination: a previously published model as a control, a trigonometry-based approach using angle and height measurements, and other model-based approaches. A linear model resulted in a formula to calculate the head angle of any plant based solely on two height measurements, the highest point of the plant at both bloom (R5) and maturity (R9). Calculations of heritability and correlation suggest this method has created a precise alternative to existing estimation methods. The resulting formula has the potential to be paired with measurements from high-throughput phenotyping methods, such as those facilitated with drones and ground robots, to fully automate the process of collecting head inclination data.

Brown patch (Rhizoctonia spp.) is a major disease of turf-type tall fescue (TF) [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.]. Many cool-season turfgrass lawns consist of species mixtures or cultivar blends, but the exact proportion of resistant cultivars in blends and mixtures to effectively reduce disease has not been well documented. A field study was conducted in West Lafayette, IN, and Blacksburg, VA, during 2022 and 2023 to determine the brown patch severity of various blend ratios (0%, 25%, 50%, 75%, and 100% by weight) using a brown patch susceptible and resistant TF cultivar. Additionally, mixtures (90% and 10% by weight, respectively) of TF and Kentucky bluegrass (Poa pratensis L.) with a susceptible and resistant TF cultivar were evaluated. Seasonal appearance/turf quality and brown patch severity were visually determined, and area under the disease progress curve (AUDPC) was calculated. Turf quality and brown patch severity were similar at both locations. Additionally, blends and mixtures containing ≥75% of the resistant cultivar maintained higher average visual quality across both locations compared to the susceptible cultivar alone. Between the two mixtures, the inclusion of a resistant TF cultivar maintained higher canopy density and increased the proportion of TF at both locations. Blends and mixtures containing ≥75% of a resistant cultivar reduced brown patch AUDPC by 71% and 83% in 2022 and 2023, respectively, when compared to the 100% susceptible cultivar. This field study reinforces the importance of selecting resistant TF cultivars to reduce seasonal brown patch symptoms in cool-season turfgrass lawns.

Optimizing phosphorus (P) application in corn (Zea mays L.) silage production systems to align with crop P requirements while sustaining soil test P (STP) levels can help mitigate environmental risks and enhance farm profitability. The objectives of this study were to characterize P balances of corn silage fields in New York, their drivers, relationships between P balances and field STP and nitrogen (N) balances, as well as the impact of manure application practices on balances. Field-level balances (supply–uptake) for P and N were derived for 994 field observations across eight dairy farms and 5 years. On average, P balances were low (11 kg P ha⁻¹) with a wide range across farm averages (−11 to 30 kg P ha⁻¹). Across farms, P was applied at higher rates to fields with adequate STP than to lower STP fields, indicating potential opportunities for reallocation of P within farms. Phosphorus balances were positively related to N balances. Manure nutrient utilization indicated that N-based applications would lead to large positive P balances in all farms. Phosphorus-based manure applications could cover on average 51% of corn N requirements under current farm manure application practices. This could be increased up to 85% when maximizing the utilization of manure inorganic N. Management alternatives to prevent excessive P balances include improving diet formulation to reduce P excretion, reducing animal density, exporting manure, implementing manure treatment technologies that conserve N and/or remove P, combining appropriate rates of manure and fertilizer, and maximizing manure inorganic N utilization in field applications.