Agronomy Journal最新文献

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.

Despite the rapid expansion of cashew cultivation in Ghana's forest–savanna transition zone (FSTZ), empirical evidence remains limited on how different cashew (Anacardium occidentale L.) cropping systems and farm locations influence soil properties and cashew tree performance. This study assessed the effects of three cashew-based cropping systems, agroforestry (cashew integrated with timber or fruit trees), intercropping (cashew combined with food crops), and monocropping, as well as the spatial distribution of cashew plantation within the FSTZ, on soil physicochemical properties and cashew tree performance. Soil physicochemical properties, cashew growth parameters, and nut quality were systematically evaluated using standardized analytical methods. Results showed that while most of the soil physicochemical parameters measured were similar across the cropping systems and farm locations, soil infiltration was highest in the agroforestry system (0.067 mm s⁻¹), followed by the intercropping system (0.043 mm s⁻¹) and the monocropping system (0.039 mm s⁻¹). Water potential was near zero in agroforestry, while litter fall and leaf mass per unit area were comparatively lower. Stem expansion was greater in monocropping and intercropping, as was the weight of the nuts. Individual nuts from the upper farms weighed 0.96 g less than those from the middle and lower farms. The individual effects of cropping systems and farm locations significantly influenced the physiology and nut quality of cashew plants in the FSTZ of Ghana. Findings indicate that farm diversification, particularly intercropping cashew with food crops during the first ten years of cultivation, can enhance the quality of cashew yield and overall productivity.

Environmental policies are a common means to reduce the impact of nitrogen (N) and phosphorus (P) fertilizers on the environment. This case study investigates the fertilizer formation policy (FFP) associated with N and P management in China. The results from a farmer survey (n = 183) showed 12.8% increase in FFP adoption overall, with adoption rising by 16.4% in cereal and oil crop farms but remaining unchanged in cash crop farms. The FFP resulted in an 8.7 kg P₂O₅ ha⁻¹ decrease in the application of surplus P without obvious effect on farm revenues; however, the N surplus unexpectedly increased by 7.9 kg N ha⁻¹. This swapping was attributed to the higher N:P ratio of formulated fertilizers compared to traditional compound fertilizers, as well as the unchanged physical fertilizer dosage. Scenario analyses indicate that even if farmers adopt formulated fertilizer at recommended dosages, the issue of N and P swapping remains. To achieve greater improvement of nutrient use efficiency, more precise fertilizer formulas are needed. Additionally, farmers need to be encouraged to adopt best management practices. This includes conducting conversation-based promotion, diversification of formulated fertilizer products, enhancing economic incentives, and multi-stakeholder collaboration. In conclusion, these findings provide critical insights for improving both N and P management and practical improvement in promoting the widespread adoption of formulated fertilization practices.

Spatiotemporal fusion addresses challenges in crop growth monitoring: namely, spatial discreteness of high-resolution imagery and spectral mixing in high-temporal-frequency data. These can hinder accurate yield and phenology estimates, especially in fragmented semi-arid landscapes. To improve winter wheat monitoring, we quantitatively and qualitatively evaluated two normalized differential vegetation index (NDVI) fusion methods: the spatial and temporal nonlocal filter-based fusion model (STNLFFM) and enhanced spatial and temporal adaptive reflectance fusion model (ESTARFM). Our primary focus was to address the limitations of MODIS data in crop phenology monitoring, specifically to resolve the challenges of spatial and temporal resolution. STNLFFM, incorporating inter-image coefficients and temporal variation, outperformed ESTARFM by eliminating stripe artifacts from prolonged high-resolution data gaps. Additionally, assimilating NDVI data via the four-dimensional variational (4DVAR) method resulted in improved accuracy, with a 6.001% mean absolute percentage error in leaf area index (LAI) estimation, compared with 6.285% using the CERES-Wheat model. Yield estimation accuracy was enhanced by 2.734% through the 4DVAR-assimilated LAI, particularly in addressing inaccuracies in mountain-cropland transition zones. This study addresses this gap by providing an integrated spatiotemporal fusion framework that mitigates data quality and scale mismatches, thereby improving the accuracy of crop growth monitoring and yield predictions. This study highlights the following: (1) the operational advantages of STNLFFM in fragmented landscapes and (2) the potential of variational assimilation to reduce model uncertainties. The proposed approach is applicable to precision agriculture in topographically complex regions and provides a scalable solution for addressing mixed-pixel challenges in the Earth's observational data.

Organic dry bean [Phaseolus vulgaris (L.)] production presents an opportunity for expanding diversified farming in the Northeast and Upper US Midwest. Cultivar trials were conducted in 2023 and 2024 in New York, Vermont, Wisconsin, and Maine evaluating 32 cultivars across black, navy, pinto, small red, and specialty market classes. Trials assessed yield, pod height, and uprightness under certified organic management. Surveys evaluated consumer preferences for taste, texture, appearance of beans, and willingness to pay for organically produced beans across marketplaces. Modern commercially available market classes outperformed specialty cultivars in yield, with average yields of 3840 ± 113 kg ha⁻¹ for pinto beans, 3730 ± 80.7 kg ha⁻¹ for black beans, 3560 ± 94.8 kg ha⁻¹ for navy beans, 3470 ± 122 kg ha⁻¹ for small red beans, and 2660 ± 64.4 kg ha⁻¹ for specialty beans; navy and black market classes scored higher in uprightness than pinto, small red, and specialty market classes in seven of eight site-years. Greater variability was observed at the cultivar level for yield, uprightness, and pod height. Survey results revealed preferences for specialty cultivars based on flavor and seed coat appearance, with respondents willing to pay up to $11.00 per pound for organic dry beans in direct markets. Breeding and developing optimized management strategies for organic specialty dry bean production could improve production and allow growers to access high-value markets, including direct-to-consumer sales, in the Northeast and Upper US Midwest.