Effects of different biochar and mycorrhiza applications on nutrient uptake, carbon fixation and yield of maize under greenhouse and field conditions

The study aimed to investigate the effects of biochar and mycorrhiza applications on maize yield, nutrient uptake and carbon (C) binding under greenhouse and field conditions. The study was carried out during in two phases, under greenhouse and field conditions, on Menzilat series soil located in Çukurova University Research Farm. In the greenhouse study, 3 different feedstock materials were biochared (BM). Produced biochars from citrus pruning wastes (TA), chicken manure (TG) and biogas production plant wastes (BA) at 0%, 1% and 2% doses (BD) were established in 3 different mycorrhiza species (control, indigenous mycorrhiza (DM) and Rhizophagus Clarus. Effective biochar material, dose range and effective mycorrhiza species were determined in the greenhouse experiment using maize (Zea mays L.) variety P2105. From the pot experiment, it was decided to use TG as the most effective bio fertilizer in terms of nutrient concentrations in plant root and shoot dry matter (6.55 g pot-1 and 11.30 g pot-1, respectively) and since there was no significant difference in statistical value between 1% and 2% BDs, 1% dose of TG used for field study. Under Ç.U. Research Farm area, a split-plot experimental was designed by biochar produced from TG with control (0%) and 1% doses and non-mycorrhizae, DM, and Rh. Clarus mycorrhizae spores were used in 2021 and 2022 for two years in the same plots planted with maize seeds. In the study, CO2 emissions were measured every 15 days after maize sowing using a LICOR-LI 8100 instrument. At harvest, root, shoot dry matter and grain yields, nutrient concentrations and CN contents were determined. Soil and plant budgets were calculated by analyzing nutrient, carbon and nitrogen contents of soil samples from rhizosphere (R) and non-rhizosphere (NR) regions at 0-15 cm and 15-30 cm soil depths. Root morphological characteristics, mycorrhiza infection rates and soil structure were analyzed as well. The results of the study showed that mycorrhizae species application significantly increased grain yield and total dry matter yield of maize plants in years I. and II. experiments. Biochar and mycorrhizae (especially Rh. Clarus) applications from TG showed dependence on mycorrhizae with a high yield increase in the -B treatment in the first and second years. In the first year experiment, DM and Rh. Clarus increased the yield by 21 and 33%, respectively, while in the +B treatment, mycorrhiza species treatments increased the yield by 42 and 23%, respectively. In the second year, grain yields of DM and Rh. Clarus increased the grain yields by 14 and 35% in the -B treatment, while in the +B treatment, mycorrhiza species treatments increased by 3 and 5%, respectively. Biochar + mycorrhiza combination was the most effective solution for carbon sequestration (58.41 tons CO2 ha-1) and also improved nutrient uptake (P, Zn). In the total organic carbon analyses performed in the first and second years, especially in the plots inoculated with natural mycorrhiza, an average of 3.97 tons OC ha-1was retained in the -B treatment and an average of 4.17 tons OC ha-1more OC was retained in the +B treatment. Mycorrhiza inoculation especially DM inoculation was resulted in higher contribution to yield and mycorrhizae dependency for both years. Keywords: Biochar, Mycorrhiza inoculation, Maize Yield, Plant root development and Carbon Budget. Mycorrhizae dependency