Search Results (798)

This study examined the windbreak effects of different tree–shrub configurations through wind tunnel experiments. Using Populus euphratica Oliv. and Tamarix chinensis Lour. as model species, six rows of front-tree–back-shrub arrangements in a triangular layout were tested under varying spacing patterns. Four spacings of P e (7.5 cm × 7.5 cm, 7.5 cm × 10 cm, 7.5 cm × 12.5 cm, 10 cm × 10 cm) and four spacings of T cs (5 cm × 5 cm, 5 cm × 7.5 cm, 5 cm × 10 cm, 7.5 cm × 7.5 cm) were analyzed. Tree–shrub combinations significantly outperformed pure stands. The configuration of P e (7.5 cm × 10 cm) with T c (5 cm × 10 cm) achieved the highest efficiency, with an average of 27.1% and a peak of 47.13% at 7 H. This configuration was effective up to 15 H and showed slower efficiency decline at higher wind speeds. Vertically, most combinations reached maximum efficiency at 20 cm height, while pure T c peaked at 51.96% at 3 cm and pure P e at 36.33% at 20 cm. Overall, the optimal configuration was P e spaced at 7.5 cm × 10 cm and T c at 5 cm × 10 cm, which not only enhanced protective performance but also reduced planting density. These findings provide valuable scientific references for designing windbreak and sand-fixing forests in arid regions, supporting ecological restoration and sustainable land management in desert–oasis transition zones. Full article

The use of Remotely Piloted Aircraft (RPA) for spraying coffee crops has expanded due to their practicality and cost reduction. This study aimed to evaluate spray rate effects on coffee crops using two RPA (T10 and T20). The study was conducted on a commercial farm with 10-year-old Coffea arabica Catucaí Amarelo. Two aircraft were used, T1 (hydraulic) and T2 (rotary nozzles). The application rates were established at 25 and 50 L ha⁻¹. The application quality was obtained by attaching Water-Sensitive Papers (WSPs) to the upper, middle, and lower parts of coffee trees, inside and outside the plants, in addition to the inter-row areas. The statistical Nested Crossed Design was applied to analyze the dataset for the experimental field with three distinct factors (RPA, application rate, and WSP position) and four replications. WSP position was the most determinant factor across all design effects, followed by RPA. The external layers of leaves received more droplets than internal parts of coffee trees. The WSP position information indicated that no droplets reached the middle interior parts of the plants or underneath them. The inter-row positions (soil) received significantly more drops than the coffee plants, regardless of application rate or RPA. The potential for drift to the soil was high in both applications. The Potential Drift Risks were more significant for RPA T2. Future studies may deepen understanding of the relationship between coverage and specific application models for coffee farming, as traditional application methods require improvements. Full article

Tree planting strategies play a critical role in improving local wind environments. This study investigates the effects of tree crown morphology and planting layout on wind regulation at two vertical levels, pedestrian height (1.5 m) and low-altitude canopy level (5 m), in Macau, a high-density subtropical city. Field microclimate measurements were combined with computational fluid dynamics (CFD) simulations to quantify the performance of three typical crown morphologies (ellipsoidal, cylindrical, and conical) under six planting configurations. Results reveal differentiated impacts across heights; under single trees and opposite tree plantings, ellipsoidal crowns produced the least wind reduction at 1.5 m but the strongest blockage at 5 m, while conical crowns caused substantial attenuation at 1.5 m yet allowed faster wind recovery at 5 m. Planting layouts further modulated these effects; a single-row of ellipsoidal crowns balanced pedestrian ventilation with upper-level wind protection, whereas opposite tree pair planting, enclosure planting and curved planting displayed contrasting performances depending on species morphology. The findings demonstrate that optimizing tree morphology and layout can precisely regulate ventilation and sheltering across height layers. This study provides scientific evidence for vegetation configuration in hot–humid high-density cities, supporting climate-responsive urban planning and design. Full article

Effective implementation and optimization of organic amendments and other management practices is essential for sustainable organic vegetable production, yet needed information is lacking on the effects and benefits of different organic matter amendments and pest management approaches under Northeastern USA production conditions. The impacts of soil amendments of biochar or humus (soluble humate complex) in conjunction with compost, as well as the presence or absence of an early-season insect netting row cover (mesotunnels), were evaluated on soil chemical and biological properties, crop development and yield, and disease and pest issues in organic vegetable production, as represented by legume (green snap bean), cucurbit (green zucchini squash), and amaranth (garden beet) vegetable crops, in a three-year field trial in Maine. Composted cow manure and a commercial organic fertilizer alone were included as controls. All plots were either covered or not covered with a permeable insect netting row cover from the time of planting until flowering. All compost-based amendments increased soil pH; organic matter; microbial activity; crop yields; and K, Mg, and Ca content relative to a fertilizer-only treatment. Biochar amendments further increased soil pH, CEC, and Ca content above those of compost alone and also resulted in the overall highest yields of bean and zucchini but were not significantly greater than with compost amendment alone. Humus amendments did not improve soil characteristics, with some indications of potential reductions in emergence and yield. Insect netting substantially improved yield of zucchini (by 59%) and somewhat improved bean yield (by 11%), in addition to improving plant emergence and reducing insect leaf damage, but it did not reduce powdery mildew on zucchini or provide any significant benefits for beets. These results help define specific management practices to improve organic vegetable production and provide useful information and options for growers. Full article

Beet armyworm (BAW), Spodoptera exigua (Hübner), is a polyphagous and migratory lepidopteran pest that causes damage to a broad range of host plants, including row crops and vegetables, with increasing reports of insecticide-resistant populations. Understanding its movement ecology is essential for integrated pest management (IPM) and insect resistance management (IRM) programs. We investigated the population dynamics and migratory origins of BAW during the 2024 cropping season in two counties of the Florida Panhandle, USA. Larval sampling and adult pheromone trapping were conducted in commercial peanut fields, and hydrogen stable isotopes were used to infer the probable geographic origins of moths. Across the season, the presence of BAW accounted for 7.1% of all individuals collected, with infestation occurring only in July and August. Moth captures were significantly higher in the eastern Florida panhandle than in the western Florida Panhandle. Stable isotope analysis revealed four distinct migratory patterns, with most BAW likely originating from South Florida, the Caribbean, or the central and southern United States, indicating northward movement. Our findings provide critical insights into the movement ecology of BAW and highlight its implications for outbreak forecasting, resistance management, and regional IPM/IRM strategies in the southeastern United States. Full article

The performance of large-scale photovoltaic (PV) power plants is strongly influenced by array layout parameters including module tilt angle, azimuth angle, and row spacing. These geometric variables jointly determine solar irradiance geometry, shading losses, and land-use efficiency, affecting annual energy yield and levelized cost of electricity. To achieve multi-objective comprehensive optimization of array layout parameters for a PV power generation system, a collaborative optimization strategy for PV array layout based on the lemur optimization (LO) algorithm is proposed in this paper. The method couples the Perez anisotropic irradiance model with a dynamic shading irradiance geometric model to simulate the effective insolation, incorporating land availability, shading thresholds, and maintenance access requirements. In addition, the LO algorithm is employed to solve resulting nonlinear and constrained problems, enabling an efficient global search across large parameter spaces. The case studies in Lianyungang, Dalian, and Fuzhou City show that the proposed scheme based on the LO algorithm improves annual energy yield compared with the existing optimization schemes, providing new theoretical methods and engineering application paths for the optimal layout of PV arrays. Full article

The development of an efficient agricultural system depends on the correct choice of crops and the management of nutrient supply and distribution within the system. This study aimed to determine how nitrogen (N) rates applied to rows of maize and tropical grass during the autumn–winter season (previous crop) influence subsequent intercropped plants. Treatments were arranged in a randomized complete block design with a split-plot scheme and four replications. The main plots comprised three cropping systems: soybean monoculture, soybean intercropped with Aruana Guinea grass (Megathyrsus maximus cv. Aruana), and soybean intercropped with Congo grass (Urochloa ruziziensis cv. Comum). The subplots consisted of four N rates (0, 50, 100, and 150 kg ha⁻¹) applied to the rows of maize and tropical grass during the previous crop. Macronutrient accumulation and efficiency indices were determined for intercropped plants. Aruana Guinea grass increased the accumulation of N, phosphorus (P), potassium (K), and sulphur (S) in the soybean crop. N applied to the previous crop negatively affected the accumulation of P, K, and S in soybean monoculture. The maximum physiological efficiency of soybean was related to N supply. The efficiency indices for Aruana Guinea grass highlighted its ability to recover residual N applied to the previous crop. Full article

Effective spatial arrangement in maize population can reduce inter-plant competition, promote root development, and enhance nutrient uptake. This study aimed to clarify how planting density and row spacing affect maize growth and yield. A four-year field experiment (2011–2014) was conducted using three planting densities (50,025, 67,500, and 100,050 plants ha⁻¹) combined with two row spacings. Grain yield increased with higher planting density, whereas plant dry weight and nutrient (N, P, K) contents declined. Higher density restricted root growth both vertically and horizontally, particularly in the 0–10 cm soil layer and inner root zone. Narrower row spacing increased grain yield, plant dry weight, and shoot nutrient contents and improved vertical and inner-zone root growth while reducing growth in the outer root zone. At the highest density, these effects were most pronounced in fine roots (<2 mm diameter), with significant increases in root length and surface area in the 0–10 cm layer in both vertical and inner horizontal zones. Overall, higher density intensified root competition and inhibited root development, whereas narrower row spacing alleviated such competition, enhanced nutrient acquisition, and improved crop yield. These results highlight the central role of fine roots in mediating maize responses to planting density and row spacing, suggesting that a moderate planting density (~67,500 plants ha⁻¹) combined with narrower row spacing is optimal for balancing root development and yield. Full article

Corn–soybean strip intercropping (abbr. CSSI system) can enhance species biodiversity and ecological services for ecological control of insect pests. To improve its effectiveness and fully utilize it to improve ecological control of insect pests and crop production, two monoculture types of corn (C) and soybean (S), and two strip intercropping patterns (i.e., C3S3 and C3S4, indicating three rows of corn strip intercropped with three and four rows of soybeans respectively), were conducted to assess the CSSI system’s (i.e., C3S3 and C3S4) impacts on the abundance of insect pests and crop yields by a two-year field experiment. The results indicated that a total of 11 species of insect pests were found in the CSSI system. Compared with C or S monoculture, the community indexes of insect pests (including the Shannon–Wiener diversity index (H), the Pielou’s evenness index (E), and the Margalef’s richness index (D)) increased, and the Simpson’s dominance index (C) decreased in the C3S3 and C3S4 patterns in 2022. Compared to the C and S monoculture, the CSSI system decreased the population dynamics of total insect pests and the key insect pests Trialeurodes vaporariorum on corn and soybean plants, respectively. In the CSSI system, T. vaporariorum exhibited higher population dynamics on corn plants than on soybean plants, indicating a preference for corn plants under the CSSI system. Moreover, the corn yield per hectare in the C3S4 pattern was significantly higher than that of the C monoculture in 2022–2023. The biomass per plant and the 1000-grain weight of corn in the C3S3 pattern were significantly lower than that in the C monoculture and C3S4 pattern in 2022. The biomass per plant, the 1000-grain weight and yield per hectare of soybean in the C3S3 and C3S4 patterns were significantly lower than that in the S monoculture in 2022–2023. The land equivalent ratio (LER) was <1.0 in the CSSI system, posing yield loss risk for soybeans in the CSSI system. The competitive ratio (CR) of corn was greater than soybean in the CSSI system. In addition, the yield of corn and soybeans were not significantly correlated with the abundance of total insect pests, while the soybean yield was significantly positively correlated to the abundance of T. vaporariorum. In conclusion, it is presumed that the CSSI system can decrease the abundances of insect pests, particularly key insect pests, and maintain their community stability, thereby preventing insect pests’ outbreak. However, the CSSI system is disadvantageous for soybean yield, as it cannot fully utilize land resources and may pose a risk of system yield loss. Full article

The spatiotemporal dynamics of soil nutrients in the crop row zone are critical determinants of crop yield, necessitating precision fertilization for optimal plant growth. However, previous studies have predominantly focused on plant-available nutrient status at the scale of entire cropping systems, yet a granular understanding of their distribution patterns across precise temporal and spatial dimensions remains limited. Therefore, this study investigated maize–legume intercropping systems to quantify the dynamics of soil alkaline-hydrolyzable nitrogen (AN), available phosphorus (AP), and available potassium (AK) across distinct growth stages, soil depths, and row positions. The experiment comprised five treatments: maize–soybean intercropping, maize–peanut intercropping, and monocultures of maize, soybean, and peanut. Throughout the two-year study, maize–soybean intercropping significantly enhanced the plant height of both maize and soybean relative to their respective monocultures (p < 0.05). In contrast, within the maize–peanut system, intercropping significantly promoted peanut plant height but suppressed stem diameter in both species (p < 0.05); these effects were consistent across both study years. Both systems exhibited a “benefit-sacrifice” pattern, where dry matter was preferentially allocated to maize, thereby increasing total system productivity despite suppressing legume growth. Furthermore, during the mid-to-late growth stages, intercropped maize showed an enhanced capacity for nitrogen uptake from deeper soil layers. In contrast, the alkaline-hydrolyzable nitrogen content in intercropped soybean and peanut remained lower than in their respective monocultures throughout the growth period, with reductions ranging from 8.49% to 34.79%. Intercropping significantly increased the soil available phosphorus content in the root zones of maize, soybean, and peanut compared to their respective monocultures. The available phosphorus content in the 0–20 cm soil layer was consistently higher than in monoculture systems, with a maximum increase of 41.70%. Moreover, intercropping effectively mitigated soil potassium depletion, resulting in a smaller decline in available potassium. This effect was most pronounced in the maize–peanut intercropping pattern within the 20–40 cm soil layer. The distribution of soil available nutrients (N, P, K) was also influenced by drip tape placement. The levels of these nutrients for soybean and peanut were higher at 50 cm from the drip tape than at 30 cm, while for maize, levels were higher at 80 cm than at 40 cm. Intercropping increased the thousand-kernel weight of maize and soybean but decreased that of peanut. Overall, the strategic row configuration optimized the yield performance of both intercropping systems, resulting in land equivalent ratios greater than 1, which indicates distinct yield advantages for both intercropping patterns. Full article

The high-latitude cold regions of northeastern China present scarce thermal resources, exhibit a short frost-free period, and lack high-yielding maize (Zea mays L.) varieties suitable for dense planting. These factors have long constrained the realization of maize yield potential under dense planting conditions. This study investigated the effects of intercropping maize varieties with different growth periods on the photosynthetic performance, yield formation, and interspecific competition. The long-season varieties Zhengdan958 (ZD958) and Xianyu335 (XY335), which are representative of the region, were intercropped with the shorter-season variety Yinongyu10 (YNY10), six intercropping row ratios (6:6, 4:4, 2:2, 1:1, 0:1, and 1:0) were set, and monoculture plots (0:1 and 1:0) were used as the controls. The results indicated that as the row ratio decreased in the intercropped plots, the leaf area index, relative leaf chlorophyll content, photosynthetic rate, stomatal conductance, and transpiration rate increased while the intercellular CO₂ concentration gradually decreased compared with those in the monoculture plots. Simultaneously, dry matter accumulation, allocation, transport efficiency, 100-kernel weight, number of kernels per ear, and grain yield progressively increased, reaching maximum values at a 1:1 intercropping row ratio. Conversely, YNY10 in the intercropped plots exhibited opposite trends in these parameters. The land equivalent ratios for all intercropped row ratios exceeded 1. During the 2023–2024 growing season, the composite population grain yield was significantly higher (p < 0.05) at an intercropping row ratio of 1:1 for ZD958 (4.11–4.26%) and XY335 (3.54–3.65%) compared with the monoculture treatments, demonstrating the strong yield advantage of intercropping. Furthermore, in the intercropping systems, ZD958 and XY335 exhibited positive aggressivity and a competitive ratio greater than 1, thus showing stronger competitive ability than YNY10. Moreover, the increased grain yield of ZD958 and XY335 effectively compensated for the ecological disadvantages of YNY10, thereby leveraging the synergistic effects of close planting and intercropping patterns to promote improvements in maize composite population productivity. Full article

As climate conditions and agricultural technologies change, the soil seed bank may increase or decrease, which may affect the species composition and abundance of weeds in crops. The research was carried out in order to evaluate the influence of hillside parts on the number of viable seeds during different seasons (spring and autumn) in agrophytocenoses, which differ in the duration of the land’s covering with plants. Soil samples have been taken out in spring and autumn at the summit, midslope, and footslope of the hill. The time of the soil sample collection and covering of agrophytocenoses had a significant effect on soil seed numbers. In autumn, the average seed amount in the soil was higher by 6.38% than in spring. The largest seed number (in spring and autumn) was evaluated in the soil of cereal–grass crop rotation with a 2.0- and 6.9-times higher seed amount compared to the rotation with a row crop and permanent grassland. During the years, hill parts had a significant effect on the seed bank in autumn. In spring, the viable seeds comprised 67.10%, and in autumn, they comprised 65.33% of the total seed number. Significantly, the highest percentage of viable seeds was estimated in the footslope of the hill. This can be related to more favorable microclimatic conditions and higher soil moisture at the footslope, where more fertile soil and organic matter naturally accumulate, creating better conditions for seed viability preservation. Full article

Crop rotation is a cornerstone of sustainable agronomy, whereas continuous monoculture can degrade soil fertility and crop vigor. A three-year field experiment (2023–2025) in Lithuania compared winter rye grown in a long-term field experiment of continuous monoculture (with and without fertilizer/herbicide inputs) with five diversified rotation treatments that included manure, forage, or cover crop phases. Unmanned aerial vehicle (UAV) multispectral imaging was used to monitor crop health via the Normalized Difference Vegetation Index (NDVI, an indicator of plant vigor). NDVI measurements at three key developmental stages (flowering to ripening, BBCH 61–89) showed that diversified rotations consistently achieved higher NDVI than monoculture, indicating more robust crop growth. Notably, the most intensive and row-crop rotations had the highest canopy vigor, whereas continuous monocultures had the lowest. An anomalous weather year (2024) temporarily reduced NDVI differences, but rotation benefits re-emerged in 2025. Overall, UAV-based NDVI effectively captured rotation-induced differences in rye canopy vigor, highlighting the agronomic advantages of diversified cropping systems and the value of UAV remote sensing for crop monitoring. Full article

Stand density is one among a multitude of factors impacting the growth of trees and their responses to climatic variables, but its effect on wood quality at the scale of anatomical structure is hardly investigated. Therefore, we analyzed the radial growth and wood structure of Siberian spruce (Picea obovata Ledeb.) and Scots pine (Pinus sylvestris L.) in an experimental conifer plantation with a wide gradient of stand density in the Siberian southern taiga. The measured and indexed chronologies of the tree-ring width (TRW), number of tracheid cells per radial row in the ring produced in the cambial zone (N), cell radial diameter (D), and cell wall thickness (CWT) demonstrated the influence of the planting density. The TRW and N have a negative allometric dependence on the stand density (R² = 0.75–0.88), likely due to competition for resources. The consistent negative dependence of the D on the stand density (R² = 0.85–0.97) is log-linear and also seems to be related to tree size, while the CWT is not significantly dependent on the stand density. These findings can be used as insights in regulating cellular structure and procuring desired wood quality by silvicultural means. Both conifer species have similar climatic reactions. We observed significant suppression of TRW and D related to water deficit in May–July (both species), as well as frosty (more for pine) and low-snow (for spruce) conditions in winters, as shown by both dendroclimatic correlation and pointer year analysis. Temporal shifts in the climatic responses indicate later transition to latewood and growth cessation in sparse stands, especially in spruce. Better performance was observed in sparce and medium-density stands for both species. Full article

Maize (Zea mays L.) is the most extensively cultivated food crop in China, and current studies on maize general combining ability (GCA) focus primarily on the genetic basis of traits. However, the dynamic trends and underlying genetic loci associated with GCA for yield-related traits during breeding remain underexplored. This study was designed to investigate the changing trends of the general combining ability (GCA) and the frequency of elite alleles among 218 major maize inbred lines from Northeast China, spanning the 1970s to the 2010s. PH6WC and PH4CV were used as testers to develop 436 hybrid combinations via the North Carolina design II (NCII) method, and these combinations were evaluated across three environments. We further analyzed the combining ability (particularly the GCA) of 16 yield-related traits and their dynamic trends during breeding, grouped into three age periods (AGE1: 1960s–1970s; AGE2: 1980s–1990s; AGE3: 2000s–2010s). We also screened for genetic loci associated with the GCA effects of these traits. Results show that breeding selection significantly affected the GCA of six yield-related traits (ear length (EL), tassel branch number (TBN), tassel main axis length (TL), kernel length (KL), stem diameter (SDR), and hundred kernel weight (HKW)). Specifically, the mean TBN_GCA value decreased from 2.51 in AGE1 to −1.28 in AGE3, and the mean HKW_GCA increased from −1.58 in AGE1 to 0.36 in AGE3. Yield per plant GCA (YPP_GCA) was positively correlated with the GCA values of EL, ear diameter (ED), kernel row number (KRN), kernel number per row (KNPR), and HKW. Association analysis identified 38 single nucleotide polymorphisms (SNP_S) related to GCA. The T/T alleles for TBN were absent in AGE1, emerged in AGE2 (1980s–1990s), and persisted in AGE3—consistent with the decreasing trend of TBN_GCA from AGE1 to AGE3. For HKW, the A/A alleles not only exhibited higher GCA (effectively improving the HKW_GCA of inbred lines) but also showed an 11% increase in allelic frequency from AGE1 to AGE3. Taken together, these results suggest that the accumulation of elite alleles is the primary factor driving the GCA improvement during maize breeding in Northeast China. Full article