Mikrobiyal gübre tasarımı ve makarnalık buğdayda (triticum durum desf.) verim denemeleri

Abstract

The excessive use of chemical fertilizers has a twofold effect on the composition of agricultural soils. First, it alters the physical and chemical properties of the soil; second, it creates an imbalance in the microbial population in the soil. These effects can disrupt the ecological balance and lead to a decrease in productivity. Furthermore, the excessive use of chemical fertilizers results in the least efficient use of the soil. The most ecologically appropriate solution to this situation is to minimize the use of chemical fertilizers by developing microbial fertilizers. In this regard, a microbial consortium was created using locally isolated Plant Growth-Promoting Rhizobacteria (PGPR) and their interactions with durum wheat (Triticum durum Desf.), a monocotyledonous plant, were investigated to evaluate their potential effects on productivity. The local PGPR isolates in question were isolated from 6 different cereal cultivation areas within the boundaries of Tekirdağ Süleymanpaşa district, yielding a total of 145 isolates. Among these isolates, 48 isolates were screened for PGB properties (nitrogen fixation, inorganic phosphate solubilization, siderophore production, indole acetic acid production, hydrogen cyanide (HCN) production, biofilm production, ammonium production, and zinc solubility) were screened. After selecting the 6 isolates with the best PGB properties, their identification was performed using 16SrDNA analysis. Based on 16S rDNA results, the six selected isolates TSR3A-34, TSR4A-51, TSR3B-106, TSR5B-129, TSR5B-131, and TSR6B-135 were respectively identified as Stenotrophomonas maltophilia, Bacillus sp., Pseudomonas koreensis, Bacillus amyloliquefaciens, Bacillus subtilis, and Pseudomonas sp. When the compatibility of the selected 6 isolates with each other was tested, the TSR6B-135 isolate was found to be incompatible with the other isolates and was not included in the consortium groups. Using the remaining five isolates, a total of 20 different microbial consortia consisting of 2, 3, 4, and 5 strains were created. These consortia were applied to wheat plants, and the growth of the plants was regularly monitored over a period of six weeks. At the end of the monitoring period, growth parameters including shoot length, root length, shoot and root dry weights, and chlorophyll content (SPAD) were measured. These measurements revealed that the consortium group most affecting wheat growth (TSR3A-34, TSR5B-129, and TSR5B-131) resulted in increases in shoot length (4.81%), shoot dry weight (19.3%), and chlorophyll content (6.06%). The PGB_invit bacterium, isolated from the Fraser's Photinia (Photinia × fraseri Dress.), was also tested for compatibility with this consortium group and, after being found suitable, was included in the consortium group. Four microbial consortium were created with three different nitrogen applications (100%, 75% and 50%) and single isolates were treated with 100% nitrogen fertilizer. Each group was repeated three times. As a result of supporting the recommended nitrogen fertiliser with a 25% reduction and the microbial consortium, increases were observed in plant height (8.36%), spike number (64.2%), grain diameter (10.8%), thousand-grain weight (5.70%), and hectolitre weight (33.10%). Furthermore, when microbial consortium applications were compared to single-strain applications, the consortium was found to be more effective in increasing wheat yield. These results indicate that chemical fertiliser use can be reduced in sustainable agriculture and that microbial consortium can be used as biofertilisers in wheat cultivation.