Search Results (3)

Sugar beet is a critical crop for global sugar production, and optimizing its growth and yield requires a thorough understanding of the effects of agronomic practices such as sowing date and nitrogen fertilization. This study was conducted in the WULS-SGGW Experimental Field in Miedniewice, Poland, during two growing seasons. The aim of the research was to determine the impact of sowing dates and nitrogen fertilization on the morphometric features and photosynthetic performance of the Lubelska sugar beet variety grown in Luvisols soil. The experiments were arranged as split-plot designs (SPDs) with four replications. The factors of the experiment were the sowing date (optimal and delayed by two weeks) and nitrogen fertilization at doses of 0, 60, and 120 kg N·ha⁻¹. The photosynthetic activity of sugar beet plants was measured four times during the growing season using chlorophyll fluorescence (ChlF) parameters. Morphometric features were determined by collecting sugar beet plants after each chlorophyll fluorescence measurement. The obtained results demonstrate the significant effect of nitrogen doses on the morphometric parameters of aboveground biomass. Increasing nitrogen doses also differentiated chlorophyll fluorescence parameters, such as F_V/F₀, F_V/F_M, PI_ABS, ET₀/CS₀, and ET₀/CS_M. A two-week delay in sowing affected both the fluorescence parameters and morphometric features of sugar beet, highlighting the interaction between agronomic practices and plant physiology. Full article

Weed coexistence with an agricultural crop can negatively affect its growth, development, and yield. From this perspective, this study aimed to evaluate weed management strategies and their effect on the agronomic parameters of cowpea cultivation in direct (SPD) and conventional (SPC) planting systems. The experiment was set up in a completely randomized block design with a split-plot arrangement with four replications. The plots received a source of variation referring to the planting systems (direct and conventional planting), and the subplots corresponded to ten weed management strategies (manual hoeing 18 days after planting (DAP); at 36 DAP; at 54 DAP; at 18 and 36 DAP; at 18 and 54 DAP; at 18 and 72 DAP; at 36 and 54 DAP; at 36–72 DAP; at 18, 36, and 54 DAP; and a control with no hoeing). Density and dry mass evaluations of the cowpea plants were performed at harvest (72 DAP) by determining the number of pods per plant, pod length, number of grains per pod, 1000-grain mass, and yield. A total of 28 species distributed in 12 botanical families were identified in the two cultivation systems. The family Poaceae showed the highest frequency, with 25% of the species identified. At the end of the assay, treatment 20 had the highest positive influence and provided significant quantitative gains to the complex of traits related to cowpea production (SPD and hoeing at 18, 36, and 54 DAP). UPGMA cluster analysis and canonical discriminant analysis were performed and allowed a better classification of the evaluated treatments. It was observed that the first two canonical variables explained 90.8% of the total variance contained in the original variables. The use of SPD with weeding at 18, 36, and 54 days after planting provides greater weed control and significant quantitative gains for the complex of characteristics related to cowpea production. The results underscore the importance of choosing the correct cropping system and implementing effective weeding practices to optimize weed control and improve crop performance. Full article

Additive manufacturing of continuous carbon fibre-reinforced polymer (CCFRP) parts enables the production of high-strength parts for aerospace, engineering and other industries. Continuous fibres allow for parts to be reinforced along the load path, multiplying their mechanical properties. However, current additive manufacturing processes for producing CCFRP parts do not optimally meet the requirements of the matrix. With resin- and extrusion-based processes, the time-consuming and costly post-processing required to remove support structures severely limits design freedom, and producing small batches requires increased effort. In contrast, laser sintering has proven to be a promising alternative in an industrial environment, allowing the production of robust parts without support structures in a time-efficient and economical manner for single and small-batch production. Based on a novel laser-sintering machine with the automated integration of continuous fibres, a combination of the advantages of the laser-sintering process and the advantages of continuous fibres is to be achieved. This paper describes an experimental analysis and optimisation of this laser-sintering machine using design of experiments. The processing time for fibre integration could be reduced by a factor of three compared to the initial state. Full article