Browsing by Author "Agiragac, Zubeyir"

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Combined Applications and Multi-Faceted Evaluations of Humic Acid, Seaweed, and Vermicompost With Chemical and Organo-Mineral Fertilizers on Corn, Part I: Chlorophyll Concentration
(Taylor & Francis inc, 2025) Agiragac, Zubeyir; Celebi, Seyda Zorer
This study investigated the effects of various fertilizers on the leaf chlorophyll content of the Simpatico (FAO300) silage corn variety under field conditions. Different application combinations were tested, including treatments with and without foliar fertilizers. The foliar fertilizers used were seaweed (SW), humic acid (HA), and vermicompost (VC), combined with granular fertilizers DAP, UREA, OMB, and OMT. Granular fertilizers were applied to the soil, while foliar fertilizers were applied at four different stages: the 4-6 leaf period, 11-13 leaf period, 14-16 leaf period, and at corn tassel. Chlorophyll content in plant leaves was measured using a SPAD-502 device during these periods. The highest SPAD chlorophyll ratios were recorded with OMB-OMT (42.583) and DAP-OMT (42.150) treatments, which did not include foliar fertilizers. Conversely, the lowest SPAD chlorophyll ratio, 28.983, was observed in the DAP-UREA treatment. Treatments with foliar fertilizers resulted in an increase in SPAD chlorophyll by 11.3% to 15.7%, with the greatest improvements observed with vermicompost and humic acid, compared to treatments without foliar fertilizers. Additionally, analysis of periodic effects showed that the highest SPAD chlorophyll ratios were found during the third and second measurement periods, while the lowest ratios were observed in the first measurement period. The use of organo-mineral fertilizers and foliar applications of vermicompost and humic acid were found to enhance the leaf chlorophyll content of corn.
The Impact of Climate Change on the Main and Second Crop Production of Different Corn Varieties in the Continental Climate Zone
(National Agricultural Research & Development Inst, 2026) Agiragac, Zubeyir
Under changing climatic conditions, identifying crop varieties with different maturity characteristics has become increasingly important to ensure yield stability and efficient use of production periods. The study was conducted in 2021-2022 at the research fields of the Department of Field Crops, Faculty of Agriculture, Van Y & uuml;z & uuml;nc & uuml; Y & imath;l University, across four periods covering both main and second cropping seasons. Corn varieties representing different FAO maturity groups - early (FAO 300), medium-early (FAO 400), medium (FAO 500-600), and medium-late (FAO 680) - were evaluated using a randomized complete block design with three replications. Measured traits included plant height (PH), forage yield (TF), dry matter (DM), dry matter ratio (DMR), number of leaves (NL), leaf weight (LW), cob weight (CW), and stem diameter (ST). In the main crop, medium and medium-late varieties showed the highest PH and DM, while CW and ST were also greatest in these groups. In the second crop, early and medium-early varieties performed better in PH, CW, and DM. Forage yield (TF) was highest in medium varieties during the main crop, but medium-early varieties were superior in the second crop. These results indicate that each maturity group adapts differently to seasonal conditions, providing specific advantages under varying production periods. Overall, these results demonstrate that the strategic use of different maturity groups according to seasonal conditions not only enhances yield performance but also supports sustainable and resilient forage corn production under variable climate conditions.