Agronomy Journal最新文献

Potassium (K) deficiency is a common yield-limiting factor in Arkansas soybean (Glycine max (L.) Merr.) production that can be addressed with innovative supplemental fertilizer application. An established leaf sampling protocol and dynamic critical concentration allow accurate diagnosis of K deficiency with corresponding recommendations for corrective, in-season K fertilizer applications at site-specific rates and times to reach anticipated yield goals. However, the profitability of in-season K fertilizer applications to irrigated soybean remains unclear. Research was conducted in Arkansas from 2021 to 2023 to evaluate multiple rates of in-season applications of muriate of potash to soybean at 15 and 30 days after first flower (DAR1). The economic ramifications of in-season fertilizer applications were quantified by calculating yield averages, partial returns (PRs), and regret when comparing PR to not fertilizing, each assuming 5-year average prices for fertilizer and soybean grain. Significant yield responses to in-season potash fertilizer were found at both 15 and 30 DAR1 times. These yield increases translated to large increases in PR or lower regret when compared to using no fertilizer. Corrective applications of 74–112 kg K ha⁻¹ were often considered optimal, with risk assessments provided to allow informed decisions. Results were summarized by category of leaf-K concentration, and treatment averages were provided to calculate payoff matrices for 15 and 30 DAR1 times. The resulting payoff matrices can be used as a decision support tool with any grain and fertilizer price to facilitate informed management decisions that optimize profitability as soybean and fertilizer prices impact optimal outcomes.

Widely used as inoculants in agriculture, nitrogen-fixing bacteria can be associated with other plant growth-promoting microorganisms (PGPMs) to increase crop grain yield. This study aimed to evaluate whether co-inoculation with Rhizobium tropici and Azospirillum brasilense associated with microalgae or cyanobacteria enhances common bean (Phaseolus vulgaris) grain yield and its economic gains in contrasting sandy and clayey soils. Water-soluble protein content and indole-3-acetic acid (IAA) production of two cyanobacteria (Anabaena cylindrica and Calotrix brevissima) and six Chlorophyta microalgae (Nannochloropsis oculata, Haematococcus pluvialis, Muriellopsis sphaerica, Chlorella protothecoides, Chlorella vulgaris, and Botryococcus braunii) were determined. Anabaena cylindrica and C. brevissima had the highest IAA production, 336.7 ± 44.7 and 94.1 ± 11.8 µg IAA mg⁻¹ of protein, respectively. Two field experiments were carried out to evaluate the triple inoculation of these Chlorophyta microalgae and cyanobacteria associated with R. tropici plus A. brasilense on the agronomic efficiency and profitability of common bean. Co-inoculation of C. vulgaris plus R. tropici and A. brasilense in common bean had grain yield of 1277.5 kg ha⁻¹ in clayey soil and 2960.3 kg ha⁻¹ in sandy soil, increasing by 219.7 and 656.0 kg ha⁻¹, respectively, in relation to double inoculation of R. tropici + A. brasilense. In the sandy soil, common bean with triple co-inoculation had the highest profit ($956 ha⁻¹), which was 25.6% higher than the N fertilized plants. Co-inoculation with PGPMs generated the highest economic gains, and in addition, it is an eco-friendly agronomic practice for sustainable food production.

Potato (Solanum tuberosom) is a globally significant crop in relation to the scale of its consumption, being the third most consumed worldwide. The overall sustainability of global agriculture is increasingly of concern, specifically in relation to increasing anthropogenic emissions of the greenhouse gas nitrous oxide (N₂O) emissions from nitrogen fertilizer additions to croplands and its contribution to climate change. Against this backdrop, a meta-analysis of 119 experimental comparisons from 18 studies—spanning 19 study sites in 10 countries—was employed to investigate the impact of irrigation, cumulative water input, N fertilizer application rate, soil pH, and soil texture on cumulative N₂O fluxes and tuber yield in potato production. Compared to non-fertilized controls, N₂O emissions from fertilized potato production decreased by 34% when irrigation provided 61%–90% of total water input (corresponding to averages of 321–473 mm). Likewise, N₂O emissions increased by 53% with 200–475 mm seasonal water input and by 37% with N fertilization rates of 101–200 kg N fertilizer ha⁻¹. Furthermore, soil pH between 7.1 and 7.5 reduced emissions by 6%, while medium-textured soils showed an increase of 2%. Conversely, tuber yields from fertilized potato production were comparatively maximized under 31%–60% of water input as irrigation (7%) and 751–1025 mm cumulative seasonal water input (28%). Alongside 201–300 kg N fertilizer ha⁻¹ (97%), soil pH of 7.1–7.5 (48%), and in coarse-textured soils (49%). Overall, these findings underscore the importance of considering irrigation and N fertilization options specifically in optimizing potato production for reduced N₂O emissions and enhanced tuber yield.

Nitrogen (N) plays an important role in corn (Zea mays L.) production, but little is known of optimum fertilizer N rates for corn grain yield and nutrient composition when poultry manure such as broiler litter (BL) (Gallus gallus domesticus) is applied. Typically, farmers consider BL as a soil conditioner and often do not discount the N contribution from the BL application. Field experiments were conducted in 2020 and 2021 over three diverse environments across Alabama to determine the agronomic optimum nitrogen rate (AONR) for BL–fertilized dryland corn with five side dress fertilizer N rates (0, 84, 140, 196, and 252 kg N ha⁻¹). The study utilized a yield response curve and evaluated the effect of fertilizer N rate on grain nutrient composition. BL (4.48 Mg ha⁻¹ equivalent to 2-ton acre⁻¹) was applied to the study sites before planting each year. The AONRs for grain yield across these environments varied from 114 to 223 kg N ha⁻¹ (0.013–0.027 kg of fertilizer N per kg of grain yield ha⁻¹). The predicted grain yield at the AONRs ranged from 4.22 to 13.27 Mg ha⁻¹. Grain N concentration increased with increasing fertilizer N rate. However, the weak to nonexistent correlation between fertilizer N and other grain nutrient elements suggests that raising the fertilizer N rate does not necessarily lead to higher nutrient levels in corn grain. Overall, these findings could be useful for developing N management guidelines for corn fields that receive BL in Alabama.

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.