Agronomy Journal最新文献

Quantitative morphological parameters of the rice root system under drought stress in juvenile differentiation stage is pivotal for optimizing water management and breeding of drought-tolerant varieties in rice (Oryza sativa L.). This study aims to quantify responses of rice root morphological parameters to varying drought intensities (DI) and durations (DD) in juvenile differentiation stage by proposing a novel drought impact factor, including IF_Bi-DI (drought impact factor for total biomass under drought intensity), IF_Bi-DD (drought impact factor for total biomass under drought duration), IF_RBi-DI (drought impact factor for root biomass under drought intensity), and IF_RBi-DD (drought impact factor for root biomass under drought duration). Pot experiments were conducted during 2018 and 2019 rice growing seasons using two rice cultivars. Nanjing 9108 (conventional) and Huaidao 5 (hybrid), under different DI (including T1, T2, T3, and T4—four levels) and DDs (including W1, W2, W3, W11, and W12—five levels). The results showed that the ratio of scanned root length to the scanned root biomass, and the partition coefficient of total root biomass followed exponential functions, while the partition coefficient of scanned root biomass exhibited an S-curve relationship. IF_Bi-DI, IF_Bi-DD, IF_RBi-DI, and IF_RBi-DD correlated linearly and logarithmically with time index, respectively. Root surface and volume models adhered to S-curve functions, whereas root average diameter displayed a linear decline with root length. The validation of models developed by us demonstrated strong correlations between simulated and observed values (r > 0.73, p < 0.001), with mean absolute difference (d_a) and root mean square errors consistently below 5% and 6.095 g plant⁻¹, respectively. This study establishes first biomass-driven framework to predict root morphological parameters under drought stress in juvenile differentiation stage, offering breeders actionable insights for developing drought-resilient cultivars and enabling precision irrigation strategies to mitigate yield losses in water-limited environments.

Peanut (Arachis hypogaea L.) is a globally important crop; however, its productivity is increasingly threatened by heat stress, exacerbated by global warming. Developing heat-tolerant peanuts is crucial for sustainable production amidst rising temperatures. Unlike commercial cultivars, wild-derived peanuts possess broader genetic diversity, being naturally adapted to an array of challenging climatic conditions. Antioxidant activity and reactive oxygen species (ROS) regulation are potential indicators of heat tolerance. Studies on enzymatic activity in peanuts have focused on commercial cultivars, leaving a research gap regarding the antioxidant defense mechanism in wild relatives. This study aimed to identify peanut genotypes with superior antioxidant performance and classify their response to heat stress by increasing activity of specific enzymes to scavenge ROS. The experiment was conducted in growth chambers, using 20 peanut genotypes, 12 wild-derived and eight commercial cultivars. Heat stress (35/22°C, day/night) was imposed for 7 days at 60 days after planting, following pre- and post-stress conditions of 30/20°C (day/night). Leaf samples were collected before, during, and after heat stress. Enzymatic activities of superoxide dismutase, catalase, and ascorbate peroxidase, alongside hydrogen peroxide levels, were analyzed. Upregulation of antioxidant activities under heat stress and recovery periods highlighted their role in detoxifying ROS. AU NPL 17, BatKemp1, IpaCor2, IpaDur2, IpaDur3, MagDur1, and ValSten1 exhibited superior antioxidant enzyme activity, suggesting their potential for heat tolerance. Results also indicated different mechanisms used by peanut genotypes to scavenge ROS, such as balanced ROS scavenging, prioritization of peroxisomal or chloroplast/cytosol detoxification, and compensatory mechanisms.

Viriato, V., Rodrigues, G. S., Nunes, M. R., Adege, A. B., & Bonfim, F. P. G. (2025). On-farm observations of socioenvironmental impacts of Humulus lupulus L. cultivation in Brazil. Agronomy Journal, 117, e70175. https://doi.org/10.1002/agj2.70175

The funding statement for this article was missing. The following funding statement has been added to the article in the Acknowledgments section:

The article was funded by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Brazil (Grant Number: 2023/12485-0). The Article Processing Charge for the publication of this research was funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil (ROR identifier: 00x0ma614).

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Agroecosystem benefits provided by a winter cover crop are proportional to residue quantity and decomposition rate. For growers who plant cover crops to suppress weeds and conserve soil moisture during the cash crop growing season, it is important to understand how management decisions such as termination method impact cover crop residue quantity and quality over time. A decomposition study was conducted in Maryland at two field sites with differing soil textures in 2022 and 2023 to test the impact of two broad-spectrum herbicides frequently used for cover crop termination before cash crop planting. At anthesis, cereal rye (Secale cereale L.) plots were either mechanically terminated with a roller-crimper or left standing. One week later, chemical termination treatments (glyphosate and paraquat) were applied to half of both the rolled and standing plots. After plant death, samples of the terminated cereal rye biomass were placed in mesh litterbags, which were affixed to the soil surface between corn rows. The litterbags were then retrieved at 2, 4, 6, 8, and 12 weeks after chemical termination treatments were sprayed and at corn harvest. No differences in decomposition rates were observed when biomass loss was calculated by calendar date or by heat units. In some site-years, roller-crimped cereal rye had higher concentrations of lignin and holocellulose. No differences in residue chemistry between the chemical termination herbicides were detected. Residue of mature cereal rye terminated late in the spring will decompose slowly regardless of termination method, maintaining a persistent mulch during the cash crop season.

Starter fertilizers containing phosphorus (P) are applied to increase corn (Zea mays L.) early growth and ultimately grain yield. This study determined the rate of starter P needed to increase corn early plant growth and grain yield at differing starting soil test phosphorus (STP) concentrations with or without broadcast P application. Field trials were established at 10 site-years in Minnesota using a split-plot design. Main blocks consisted of 0 or 59 kg P ha⁻¹ broadcast pre-plant. Sub-plots consisted of liquid starter fertilizer (10-15-0 N-P-K): 0, 29, 58, and 87 kg ha⁻¹ applied on the corn seed. Analysis was conducted across sites after classifying each block per site (low, medium, high, and very high STP) according to University of Minnesota guidelines. Corn plant mass and P uptake at V5–V7 increased linearly as the rate of starter P regardless of where broadcast P was applied and initial STP concentration. Corn yield was increased by P when STP was in the low or medium STP classification, and application of starter P alone did not maximize grain yield in low P soils. The data indicate that 29 kg ha⁻¹ of the starter applied in this study is sufficient to increase early plant growth and corn yield compared to broadcast P only when STP was medium or higher. Broadcast P is needed to maximize yield when STP was low, and varying starter rates more than 29 kg ha⁻¹ will not result in a greater yield potential across sites versus broadcast P alone regardless of STP concentration.

Golf courses throughout the southern United States have begun converting fairways from hybrid bermudagrass (Cynodon dactylon × C. transvaalensis Burtt-Davy) to manilagrass [Zoysia matrella (L.) Merr.]. Recognition (trifloxysulfuron + metcamifen) can be tank-mixed with fluazifop to gradually remove hybrid bermudagrass during conversion, eliminating the need for glyphosate applications prior to sprigging and reducing disruption of play due to surface imperfections. Trials were conducted in Georgia and Tennessee during the summer of 2022 aimed at chemical plus cultural conversion of TifTuf hybrid bermudagrass fairways to Zorro manilagrass. Treatments consisted of sequential applications of glyphosate + fluazifop (industry standard) and various rates of fluazifop + Recognition applied before and after sprigging. Two applications of glyphosate + fluazifop and three applications of fluazifop + Recognition resulted in days to 80% effective manilagrass conversion (Days₈₀) values of 76–82 days, regardless of rate, while two applications of fluazifop + Recognition resulted in Days₈₀ values of 88–99 days, regardless of rate. Effective hybrid bermudagrass control (≥90%) was observed 13 weeks after sprigging in response to all treatments in Tennessee, regardless of rate, while a similar trend was observed in Georgia except for two applications of fluazifop + Recognition (47%–78% control). No phytotoxicity was observed on manilagrass throughout each trial. When combined with fluazifop, the inclusion of Recognition provides a non-phytotoxic option for the gradual conversion of hybrid bermudagrass to manilagrass without disruption in play. Further research should investigate safety of additional manilagrass cultivars and application timings.

Potassium (K⁺) is a key macronutrient for plant growth. While arbuscular mycorrhizal (AM) fungi have been shown to enhance K⁺ uptake in model legumes like barrel medic (Medicago truncatula), their effect on crop legumes such as soybean [Glycine max (L.) Merr.] is not well documented. A 2-year field study across three North Carolina regions assessed the impact of AM inoculation on soybean growth, nutrient uptake, yield, and seed quality. Trials targeted soils low in phosphorus and K⁺, using K⁺ chloride to establish high (67 kg ha⁻¹) and low (0 kg ha⁻¹) K⁺ environments. Three commercially available soybean cultivars (maturity groups IV, V, and VI) were either inoculated with AM fungi or left untreated. Measurements at 10 and 16 weeks post-planting included chlorophyll content estimation, shoot biomass, and tissue nutrient concentrations. Results indicated that environmental conditions and cultivar maturity group had the strongest influence on biomass, K⁺ uptake, yield, protein, and oil content. AM inoculation had limited impact across treatments. These findings, consistent with previous studies, suggest that AM inoculation offers minimal practical benefit for soybean K⁺ nutrition under field conditions in North Carolina. Growers should critically evaluate product claims and use caution when adopting AM inoculants expecting significant yield improvements.