The Effects of Animal Manure and Mycorrhiza Applications on Soil Carbon Fractions in Tilled and Non-Tilled Conditions

Due to long-term extensive cultivation on marginal and agriculturally suitable lands, soil organic carbon (SOC) has oxidized and released as CO₂ into the atmosphere. Furthermore, the quality of the soil and environmental safety have been further compromised by the overuse of chemical fertilizers. Despite possible trade-offs, no-till farming and the use of organic fertilizers like animal manure are advised practices to address these issues. Additionally, arbuscular mycorrhizal fungi (AMF) enhance soil aggregation and reduce the need for chemical fertilizers. However, there is limited data on the combined impact of manure and AMF on the dynamics of soil carbon in the study area, in both tillage and non-tillage scenarios. Therefore, this study aimed to investigate the effect of tillage, animal manure, and AMF application on soil carbon fractions. The study was carried out in 2023 at the Çukurova University Agricultural Research Center, Department of Soil Science and Plant Nutrition’s Research Farm, Adana/Türkiye. The experiment was set up with treatments consisting of two tillage (tilled and non-tilled) as the whole plot, two AMF (with and without AMF) as the sub-plot, and two fertilizers (with and without animal manure) as the sub-sub plot factors in a split-split-plot design, totally 24 plots. Plots that did not receive animal manure received the recommended amount of mineral NPK fertilizer for optimal maize growth. Animal manure at 25 t ha⁻¹ was applied in manure-treated plots. AMF inoculum was applied 50 mm under maize seeds. At harvest, soil samples were taken at 0-20 cm and 20-30 cm depths. The fractions of soil carbon (total carbon, organic, inorganic, active carbon, and particulate organic matter) were determined based on respective procedures. R computer program was used to analyze the data, and Tukey's test (p<0.05) was employed to compare means. The findings showed that tillage and AMF application did not significantly affect the soil carbon fractions. However, application of animal manure resulted in significant increases in total soil carbon (TC), organic carbon (OC), and particulate organic matter (POM). The study showed that the addition of fresh organic matter caused a quick rise in soil organic carbon fraction while the inorganic C remained unchanged. Given that the effects of tillage might take longer to become evident, further studies are necessary to validate these findings and better understand the long-term impacts of these soil management practices.