Agronomy Journal最新文献

Various tillage systems have limitations on soil health, such as the degradation of soil structure and organic matter under conventional tillage (CT) systems, as well as short-term soil compaction in conservation tillage systems. A 3-year field experiment was established to evaluate the integration of cover crop (CC) and organic amendments (OAs) into CT and strip tillage (ST) systems, and their impact on soil properties and cotton (Gossypium hirsutum L.) productivity. The CC was cereal rye (Secale cereale), and the combined application of animal manure and biochar constituted the OA. In the third year, differences in soil compaction between the CT and ST systems were observed when the measurements were made after tillage. Moreover, integrating CC and OA under the CT and ST systems increased the soil depth to compaction zones. Soil compaction was observed at 27.5-cm depth under CT, at 30-cm depth under CT integrated with CC and OA, at 10-cm depth under ST, and at 15-cm depth under ST integrated with CC and OA, using 2 MPa as the threshold. In general, the integration of CC and OA tended to increase soil respiration, organic matter, and available nutrients, but the effects were not consistent across years and soil depth. Despite differences in the various soil health properties, the management systems had minimum impact on cotton productivity and fiber quality, indicating the ST was effective in preparing the seedbed. Moreover, the differences in soil properties were not at yield-limiting levels within 3 years of the study.

Ammonia (NH₃) loss following manure application is an environmental concern and N loss for crop production. Manure injection typically reduces NH₃ loss compared to surface application without incorporation but increases emissions of nitrous oxide (N₂O), which is a potent greenhouse gas. Synchronizing manure in spring with cover crop (CC) growth may increase N recovery and reduce N₂O emissions compared to applying manure later in the absence of growing crops. We compared the two following manure application methods: shallow-disk injection (IM) or surface banding without incorporation (BM) to annual ryegrass (Lolium multiflorum L.) and red clover (Trifolium pratense L.) CC at two times: early spring on growing CC (EARLY) and late spring on terminated CC (LATE). The randomized split-plot block experiment was conducted at Rock Springs, PA, during 2021–2022. After manure application, we measured NH₃ for 72 h and N₂O throughout the growing season. Aboveground CC biomass, N, and C:N ratio; pre-sidedress soil nitrate; corn (Zea mays L.) stalk nitrate; and silage yield were assessed. Averaged across application times, compared to BM, IM reduced cumulative NH₃ loss, increased soil N, and resulted in 13% greater corn yield but increased yield-scaled N₂O. Compared to BM LATE, BM EARLY reduced NH₃ loss by 43%, increased CC N, reduced N₂O emission by 50%, but decreased corn yield by 11%. When IM was EARLY compared to LATE, CC N increased 84%, cumulative N₂O loss decreased 55%, and corn yield was similar. Injecting manure to growing CCs offers a strategy for reducing detrimental NH₃ and N₂O emissions and maintaining corn yield.

Bermudagrass [Cynodon dactylon (L.) Pers.] is an important forage source for ruminants in tropical and subtropical regions of the world; nevertheless, little is known about the productive and nutritional characteristics of new accessions and cultivars originating from breeding programs. Five bermudagrass cultivars (Tifton 85, Jiggs, Florida 44, Callie, and Newell) and five accessions (276, 282, 323, 286, and Missouri) were tested during the 2018 and 2019 growing seasons. Genotype × harvest interactions were detected for herbage accumulation (HA), crude protein (CP), and nitrogen yield (p < 0.05). In June, all bermudagrass genotypes showed significant variation in HA, with accession 286 being more productive than Jiggs (4.42 vs. 3.24 Mg DM ha⁻¹ harvest⁻¹, respectively, where DM is dry matter). In October, however, accession 323 had greater CP than Callie, accession 286, Newell, and Tifton 85, with average CP values of 155, 128, 136, and 137 g kg⁻¹ DM, respectively. Average in vitro digestible organic matter for accession 323 (450 g kg⁻¹ DM) was similar to that of Tifton 85 and Newell but greater than that of Missouri (393 g kg⁻¹ DM). Genotypes displayed unique responses to all traits across harvest dates. According to the principal component analysis, the accession Missouri exhibited low productive and nutritive value properties. The accession 286 showed greater CP concentration while still productive; thus, this accession will be further examined for future release to livestock or hay producers in subtropical regions worldwide.

Quantifying root length, surface area, average diameter, and volume of fully-matured corn (Zea mays L.) is labor intensive, time consuming, and costly. Accurate and efficient subsampling techniques are needed to overcome these limitations. In this study, eight corn root systems were grown to maturity in a sand-culture hydroponics system to develop and test root system subsampling techniques for accuracy (uncertainty assessment) and efficiency (time). Each entire root system was separated into coarse and fine roots, which were then composited into 65 subsamples, either visually or by mass, followed by subsample scanning to quantify root characteristics. A bootstrap non-parametric procedure was used to determine the sample size needed to represent the total root system and quantify uncertainty based on the number of subsamples analyzed. When subsamples were composited visually, as many as 60 subsamples (92% of the total root system) were necessary to represent the characteristics of the root system within ±5% of the true mean at a 95% confidence level. In contrast, when subsamples were composited by equal mass, a maximum of 15 subsamples (23% of the total root system) were needed to be representative, requiring 2 h and 15 min per root system. The findings show that separating the entire root system by coarse and fine roots and then weighing into equal mass subsamples before scanning decreased the number of subsamples and time required to accurately estimate corn root characteristics. Thus, this subsampling approach considerably reduced the effort and cost of processing corn root systems.

The medicinal constituents of Chinese herbal medicine honeysuckle (Lonicera japonica Thunb) vary at different flower stages. In order to ensure that the medicinal value is maximized, it is necessary to identify its flower stage before harvesting. However, at present, this study can only be accomplished by manual visual recognition, which is inefficient and costly. Therefore, there is an urgent need to develop an automatic detection technique with high maturity, fast detection speed, and strong model deployment capability. In order to adapt to the problems of different flower size and color texture similarity and complex background, this study chooses YOLOv5s algorithm for adaptive modification. First, a small detection layer is added to the network to enhance feature extraction and improve the accuracy of identifying small honeysuckle. Second, attention mechanism is incorporated into the backbone network to suppress background interference and improve identification accuracy. Finally, the original IoU-NMS is replaced by the DIoU-NMS algorithm, which improves the bounding box regression rate while reducing the leakage rate when overlapping or occluded. The test results showed that the P was increased from 80.0% to 92.7%, the R was increased from 78.6% to 80.2%, and the mean average precision was increased from 86.2% to 90.6%. Furthermore, the model was verified at both long range and short range, and the tests data indicate that the identification accuracy was no less than 90% in 3 m without serious occlusion. This study laid a solid foundation for accurate honeysuckle flower stage identification and provided technical support for real-time machine picking honeysuckle.

Environmental awareness about soil and water conservation in agroecosystems has shifted behaviors toward favoring conservation practices in agricultural management. Interest in conservation tillage and cover cropping has increased, but some regions encounter major challenges with adjusting management to accommodate these practices while optimizing crop production. In an Ultisol in the North Carolina Piedmont, a long-term corn (Zea mays) and soybean (Glycine max) rotation with tillage intensities ranging from no-till to moldboard plowing in a randomized complete block design was used to assess changes in physical soil properties after introducing wheat (Triticum aestivum) as a winter cover crop. Cover crop biomass was measured along with volumetric water content (VWC) and bulk density (BD) at 0–15 cm, water retention (WR), water-stable aggregation (WSA), and soil organic carbon (SOC) at 0–7.5 cm, and penetration resistance (PR) at 0–45 cm. No differences in VWC or WR could be solely attributed to cover cropping, but no-till with cover cropping had the highest macroporosity where there was no vehicle traffic. Vehicle traffic had a stronger effect on soil compaction (BD and PR) than cover cropping regardless of tillage. Conservation tillage increased WSA and SOC when compared to plow tillage, but three seasons of a wheat cover crop did not significantly change these properties, possibly because wheat produced low biomass each year (750–1900 kg ha⁻¹). Wheat had minimal effect on physical soil properties in the short term, and potential for improvement with long-term optimal cover crop management in this region requires further assessment.

The current study was initiated to assess mungbean [Vigna radiata (L.) R. Wilczek] mutant lines for yield and their attributes in the mutation generation third (M₃) generation using an augmented block design. Note that 1200 mutated mungbean lines were selected from the γ-irradiated (400–700 Gy) population and distributed into 21 blocks, along with three popular varieties (checks) replicated in each block. To evaluate mean performance, variance, and population genetics, the observations on days to flowering, days to maturity, plant height (cm), number of clusters per plant, number of pods per plant, pod length (cm), protein percentage, seed index, and seed yield (g) were measured and analyzed. All the lines under consideration showed highly significant variations for all the variables, except for days to flowering. Seventy-nine mutant lines were found to have significantly better yield attributes than checks and are currently being evaluated under station trial. Skewness and kurtosis analysis unveiled the presence of gene interactions, offering opportunities for targeted improvement and efficacy of γ rays as a mutagen, facilitating the release of variability within the population. Future mungbean breeding programs will benefit from the successful isolation of mutant plants with yield-enhancing traits, such as up to 20 clusters per plant, 71 pods per plant, 8.55 cm pod length, 26.69% protein content (5% higher than parent), and 29 gram seeds per plant. In early selection cycles without the need for replicated trials, this study demonstrated the effectiveness of the mutagen and augmented design in creating novel variations, evaluating and identifying superior genotypes with improved yield potential.

Various agronomic practices can affect the processes of aboveground dry matter accumulation (source) and grain filling (sink), resulting in yield differences. Improved source-sink relationships can facilitate the production and accumulation of assimilates to increase the productivity of winter wheat (Triticum aestivum L.). A two-season field experiment was undertaken on winter wheat during 2020–2021 and 2021–2022. In a split-split-plot design with three replicates (randomized blocks), we compared two planting modes (ridge-furrow planting with plastic mulching [RFPM]; traditional flat planting [TF]), two complementary irrigation levels (I₃₀₊₃₀: 30+30 mm; I₀: no irrigation), and three planting densities (D₁, D₂, and D₃: 240, 360, and 480 plants m⁻²). The results showed that RFPMI₃₀₊₃₀ significantly increased maximum yield by 28.5% compared with TFI₀. Although D₃ increased the number of effective spikes per unit area and duration of grain filling compared to D₂, it reduced the number of grains per spike, 1000-grain weight, and average filling rate. Compared to TF and I₀, RFPM and I₃₀₊₃₀ improved the sink/source ratio by 5.3% and 6.5%, respectively. Grain yield peaked at D₂ in the RFPM and at D₃ in the TF. Medium planting density (D₂) and complementary irrigation (I₃₀₊₃₀) during the wintering and reviving periods under RFPM can achieve better source-sink balance relationships and the maximum grain yield of winter wheat. Overall, we believe that in most cases, wheat yields are source-limited and can be improved by ridge-furrow planting with plastic mulching, complementary irrigation, and planting density regulation.

Consumer acceptance of common beans (Phaseolus vulgaris L.) belonging to the Carioca commercial group depends on the color of the seed. Therefore, producers seek bean cultivars that have a light seed coat after storage. This trait is very important for common bean breeding programs dedicated to produce a high market demand. Therefore, the objective was to propose and assess the use of a computer vision-based methodology for assessing common bean color at harvest and after storage. A total of 70 carioca bean cultivars were visually assessed using a grading scale and computer vision after harvest and 90 days after the first assessment. The images allowed the cultivars to be discriminated according to the seed coat color. The accuracies with both assessment methodologies were >0.90. In addition, the correlations between these methodologies were ≤−0.72. The coefficients of variation for computer vision were lower than 6.50, while for the visual assessment, they were >10.08. Therefore, computer vision applied to assess the seed coat color of carioca bean grains is precise and accurate and allows for better discrimination than the visual assessment. Therefore, image analysis will assist in selecting better cultivars in breeding programs.

It is necessary to increase the agronomic use efficiency of urea to reduce ammonia volatilization and increase crop yield. However, relying solely on urea for the enhanced efficiency technologies development could harm fertilizer integrity, resulting in reduced application quality and fertilizer storage time. The authors aimed at developing and characterizing the physical, chemical, and physicochemical quality of a novel enhanced efficiency fertilizers, synthesized from urea plus boron (B), zinc (Zn), nickel (Ni), or molybdenum (Mo) addition, with or without N-(n-butyl) thiophosphoric triamide (NBPT) associated. Hygroscopicity, hardness, salt index (SI), pH, and thermogravimetric decomposition were the parameters evaluated. Fertilizer quality was assessed through microscopic X-ray fluorescence, microtomography, and scanning electron microscopy. Micronutrients were added by coating or granulation; they were homogeneously distributed over the fertilizer's granules. The fertilizers’ hardness increased up to 86% with Zn coated compared with uncoated. Granulated urea with B, Zn, Ni, or Mo had greater internal porosity, which resulted in lower hardness. Boron and Zn addition to the fertilizers increased the hygroscopicity in average 388% and 473%, respectively, compared with hygroscopicity observed for urea. Moreover, hygroscopicity was increased by an average of 56% with NBPT addition. Micronutrients addition to the urea granules increased the SI, while thermal decomposition stages of urea were unaffected by micronutrients addition. Enhanced efficiency fertilizers require characterization before agronomic efficiency tests due to changes in their physical, chemical, and physicochemical properties. Unfavorable changes could harm granules integrity and application efficiency in the field, resulting in economic losses to the industry and farmers.