Effects of Different Carbon Sources on Growth and Soil Biological Properties of Safflower (Carthamus tinctorius L.)

In this study, the effects of different carbon sources on the growth of safflower (Carthamus tinctorius L.), soil nitrogen forms, soil enzyme activities, and leaf temperature were investigated. The experiment was conducted under greenhouse conditions in pots, and glucose, sucrose, and mannitol were applied as carbon sources, while soil without any carbon source application was used as the control. In the study, plant growth parameters such as plant height, fresh weight, and dry weight were determined. In addition, SPAD values, soil ammonium (NH₄⁺) and nitrate (NO₃⁻) contents, soil enzyme activities (catalase, dehydrogenase, and urease), and leaf temperature values determined by using the thermal imaging method were evaluated. The obtained results showed that carbon source applications generally increased plant growth parameters compared to the control treatment. Among the applications, especially the mannitol application provided higher increases in terms of plant height, fresh weight, and dry weight. It was determined that carbon applications also affected soil nitrogen dynamics and particularly caused an increase in soil ammonium content. In contrast, different changes in nitrate content were observed depending on the applications. It was determined that carbon sources increased soil enzyme activities and this indicated that soil microbial activity was promoted. Thermal imaging results showed that there were some differences among the applications in terms of leaf temperature, but these differences were not statistically significant. In general, it was determined that carbon source applications showed a tendency to support plant growth and soil biological activity in safflower cultivation.