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A field experiment was implemented at Al-Sayyada agricultural research station / Agriculture College, University of Kirkuk, during the summer growing season 2024 to examine the impact of various nitrogen fertilizer sources and planting distances between the rows on the growth, yield and quality of pearl millet. The experiment established in a Randomized Complete Block Design (RCBD) according to a split-plot arrangement with three replications. Distance between planting rows occupy the main plots which were (20, 30, 40, and 50 cm), while the subplots were for nitrogen fertilizer sources (urea, organic, liquid and nano). The data were statistically evaluated, and the means were compared by Duncan’s multiple-range test at 0.05 significance level. The results showed that the 20 cm planting distance significantly affected plant height, grain yield (tons ha−1), and grain protein yield. The 40 cm record significant values in flag leaf area, while the 50 cm showed a higher grain nitrogen percentage. However, for nitrogen fertilizer sources, the nano fertilizer significantly influenced number of days from 50% flowering till physiological maturity, flag leaf area (cm2 plant−1), plant height, and protein yield. The liquid fertilizer had significant influence on grain yield (tons ha−1), which did not significantly differ from the nano fertilizer. While, organic fertilizer improved grain nitrogen content significantly. Regarding the interactions, planting distance of 20 cm combined with nano fertilizer resulted in the highest plant height average of 295.23 cm. The interaction of 30 cm spacing with liquid fertilizer gave the highest significant value for the number of days from 50% flowering to physiological maturity, with an average of 72.00 days. Additionally, the 30 cm spacing with nano fertilizer showed a significant superiority in flag leaf area, recording 120.61 cm2 per plant. The 20 cm spacing with liquid fertilizer significantly outperformed in grain yield with 5.60 tons ha−1, and in protein yield with 37.54 kg ha−1. Finally, the 50 cm spacing combined with organic fertilizer showed superiority in nitrogen content in seeds, reaching 1.93%. The main conclusions from our experiment are that there is growing evidence that, 50 cm as a distance between planting rows improve most of studied traits. Also, nano nitrogen fertiliser had positive impact on yield and its components while grain quality affected by organic nitrogen.

To explore the bolt-grouting method of the deep roadway under three-dimensional unequal ground stress, a unidirectional coupling model of surrounding rock plastic failure and grouting diffusion considering the influence of excavation disturbance stress was established. Spatial evolution characteristics of plastic failure and grouting diffusion, and the impact of the spacing and row spacing of grouting bolts/cables on grout diffusion, were simulated by using the numerical method. The results revealed that the horizontal ground stress perpendicular to the axial direction of the roadway was the main factor inducing roadway damage. Moreover, the more significant the difference of the ground stress in three directions, the larger the plastic zone of the roof corner and floor corner of the roadway. Under different lateral pressure coefficients, the grout diffused can be approximate ellipsoid and cylinders. Furthermore, the larger the ratio of lateral pressure coefficients perpendicular to and parallel to the axial direction of roadway, the larger the diffusion length of grout in each spatial direction in the surrounding rock. In bolt-grouting support, the length of the grouting bolts/cables should be greater than the plastic zone of the surrounding rock, and the optimal relationship between their spacing and row spacing and diffusion length of grout is determined. The research results were applied in the bolt-grouting engineering for the three-level main roadway in the Haizi Coal Mine, and a good support effect was achieved. This can provide technical guidance and a method of reference for the design and parameter optimization of bolt-grouting support for roadways under deep high ground stress.

Dense cropping increases crop yield but intensifies resource competition, which reduces single plant yield and limits potential yield growth. Optimizing canopy spacing could enhance resource utilization, support crop morphological development and increase yield. Here, a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans. Of three row-spacing configurations (40–40, 20–40, and 20–60 cm) and two planting densities (normal 180,000 plants ha−1 and high 270,000 plants ha−1). The differences in canopy structure, plant morphological development, photosynthetic capacity and their impact on yield were analyzed. Row spacing configurations have a significant effect on canopy transmittance (CT). The 20–60 cm row spacing configuration increased CT and creates a favorable canopy light environment, in which plant height is reduced, while branching is promoted. This approach reduces plant competition, optimizes the developments of leaf area per plant, specific leaf area, leaf area development rate, leaf area duration and photosynthetic physiological indices (Fv/Fm, ETR, Pn). The significant increase of 11.9%–34.2% in canopy apparent photosynthesis (CAP) is attributed to the significant optimization of plant growth and photosynthetic physiology through CT, an important contributing factor to yield increases. The yield in the 20–60 cm treatment is 4.0% higher than in equidistant planting under normal planting density, but 5.9% under high density, primarily driven by CAP and pod number. These findings suggest that suitable row spacing configurations optimize the light environment for plants, promote source-sink transformation in soybeans, and further improve yield. In practice, a 20–60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.

Achieving novel improvements in crop management may require changing interrow distance in cultivated fields. Such changes would benefit from a better understanding of plant responses to the spatial heterogeneity in their environment. Our work investigates the architectural plasticity of wheat plants in response to increasing row spacing and evaluates the hypothesis of a foraging behavior in response to neighboring plants. A field experiment was conducted with five commercial winter wheat cultivars possessing unique architectures, grown under narrow (NI, 17.5 cm) or wide interrows (WI, 35 cm) at the same population density (170 seeds/m ). We characterized the development (leaf emergence, tillering), the morphology (dimension of organs, leaf area index), and the geometry (ground cover, leaf angle, organ spreading, and orientation). All cultivars showed a lower number of emerged tillers in WI compared to NI, which was later partly compensated by lower tiller mortality. Besides, the upper leaf blades were larger in WI. Finally the leaf area index at flowering showed little difference between WI and NI treatments. The rate of leaf emergence and the final leaf number were higher in WI compared to NI, except for one cultivar. Around the start of stem elongation, pseudo-stems were more erect in WI, while around the time of flowering, stems were more inclined and leaves were more planophile. Cultivars differed in their degrees of responses, with one appearing to prospect more specifically within the interrow space in WI treatment. Altogether, our results suggest that altering interrow distance leads to changes in the perceived extent of competition by plants, with responses first mimicking the effect of a higher plant density and later the effect of a lower plant density. Only one cultivar showed responses that suggested a perception of the heterogeneity of the environment. These findings improve our understanding of plant responses to spatial heterogeneity and provide novel information to simulate light capture in plant 3D models, depending on cultivar behavior.

Groundnut is a very important crop in the West and Central Africa (WCA) region, accounting for almost 70% of Africa’s groundnut production in 2019. Despite its economic importance, the crop’s yield is still low. For a high yield and profitable economic returns, optimal plant density is a fundamental crop management practice. Plant density experiments were conducted at the ICRISAT-Mali research station between 2016 and 2021 over the main rainy and dry seasons to determine the optimum density for maximum groundnut yield and economic benefits. The treatments contained row spacing of 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, and 100 cm, with intra-row spacing of 10 cm, 15 cm, and 20 cm. Results showed that when plant density was increased, dry pod yield, production value, and net economic benefit per hectare increased in a no moisture stress scenario. During the rainy season, the 40 cm × 10 cm spacing gave the highest dry pod yield (1693 kg), production value ($891.6), and net benefit ($403.5) per hectare. The highest dry pod yield (3703 kg), production value ($2173), and net benefit ($1510.2) per hectare were obtained from 30 cm × 10 cm spacing during the dry season. The number of pods per plant and 100 SW increased with lower plant densities. Therefore, it is recommended to increase plant density to at least 222,000 plants per hectare in the Sudan Savannah agroecology of WCA.

Experimental studies were conducted on the cultivation of tomatoes (Solanum lycopersicum L.) at Shandong Agricultural University, China, from 2022 to 2023. Three cultivation patterns were designed as follows: a north–south orientation with a row spacing of 1.40 m (NS-1.4m), a north–south orientation with a row spacing of 1.80 m (NS-1.8m) and an east–west orientation with a row spacing of 1.80 m (EW-1.8m). A functional–structural plant model using the open source interactive modeling platform of GroIMP was constructed for the cultivation of tomatoes. The growth of plants as well as the light distribution and light interception capacity of the crop canopy were simulated and analyzed. The impacts of these cultivation patterns on the growth, photosynthetic characteristics, fruit ripening time, quality and yield of tomato plants were analyzed. The studies revealed that compared with the NS-1.4m treatment, the canopy light interception of tomato plants under the NS-1.8m and EW-1.8m treatments increased by 6.08% and 9.80% in a winter–spring crop and 6.80% and 19.76% in an autumn–winter crop, respectively. Their plant height, leaf area, aboveground dry matter accumulation, leaf net photosynthesis rate as well as the lycopene, vitamin C and sugar–acid ratio of the fruit all exhibited increasing trends, while fruit ripening was accelerated. The yield of the NS-1.8m and EW-1.8m treatments increased by 3.92% and 6.18% in a winter–spring crop and 4.17% and 9.78% in an autumn–winter crop, respectively. Structural equation modeling was used to further analyze the data, confirming that the cultivation of an east–west orientation with wide row spacing is beneficial for tomato cultivation in Chinese solar greenhouses. This cultivation pattern maximizes the canopy’s light interception, thus leading to improved fruit quality and yield. Overall, this study provides valuable insights for optimizing the cultivation pattern of solar greenhouse crops.

Waxy maize (Zea mays L. ceratina) is extensively cultivated and exhibits substantial market demand in China; however, its yield and quality improvement remain constrained by relatively underdeveloped cultivation techniques. Optimizing plant density and row spacing is critical to improving the yield and nutritional quality of waxy maize, yet their combined effects remain insufficiently explored. A split-plot design evaluated two plant densities, i.e., 5.25 × 104 plants ha−1 (PD5.25) and 6.75 × 104 plants ha−1 (PD6.75), and three row configurations, i.e., 80 + 40 cm wide–narrow rows (RS8-4), 100 + 20 cm wide–narrow rows (RS10-2) and conventional 60 + 60 cm equal rows (RS6-6). This study aims to identify the optimal cultivation configuration for waxy maize in the Loess Plateau region. Results showed that the RS8-4 configuration maximized agronomic traits, dry matter accumulation, and yield relative to RS6-6 and RS10-2 treatments. Specifically, RS8-4 reduced the insertion angle of the lower ear leaf by 12.4% (p < 0.05) and ear height by 8.3% while increasing yield by 19.86–20.00% compared to RS6-6 and RS10-2 treatments. At fresh-market maturity, dry matter accumulation under RS8-4 treatment increased significantly by 34.0% with higher plant density. Under PD6.75, RS8-4 boosted dry matter by 29.8% and 39.4% versus RS6-6 and RS10-2, respectively. Under the RS8-4 and PD6.5 configurations, dry matter accumulation reached 13.56 t ha−1 and a yield of 9.94 t ha−1 was achieved in 2022. In summary, the combination of the PD6.75 density and the RS8-4 row spacing configuration achieved the optimal yield for the ‘Jinnuo 20’ cultivar in the Loess Plateau region. This approach provides a scalable planting framework for high-yield waxy maize production in the area, while demonstrating that optimized plant density and row spacing represent not only a key technical measure for enhancing productivity but also a core agronomic strategy for improving resource-use efficiency.

To elucidate the photosynthetic physiological mechanisms influencing alfalfa (Medicago sativa L.) yield and quality under varying planting densities, the cultivar ‘Zhongmu No.1’ was used as experimental material. The effects of different row spacing (R1, R2, R3) and seeding rate (S1, S2, S3, S4, S5) combinations on chlorophyll content (ChlM), nitrogen flavonol index (NFI), chlorophyll fluorescence parameters, forage quality, and hay yield were systematically analyzed. Results showed that alfalfa under R1S3 treatment achieved peak values for ChIM, NFI, EE, and hay yield, whereas R1S4 treatment yielded the highest Fv/Fm and CP content. Redundancy analysis further indicated that yield was most strongly associated with ChlM, NFI, Y (II), and qP. Y (II), and qP significantly influenced alfalfa forage quality, exerting negative effects on ADF and NDF, while demonstrating positive effects on CP and EE. In conclusion, narrow row spacing (15 cm) with moderate seeding rates (22.5–30 kg·hm−2) optimizes photosynthetic performance while concurrently enhancing both productivity and forage quality in alfalfa cultivated, establishing a theoretical foundation for photosynthetic regulation in high-quality and high-yield alfalfa cultivation.