Integrated effects of organic amendments and microbial inoculants on soil quality and wheat growth performance

The study examined the differences in wheat plant growth and soil traits under different treatments of organic materials and microbial inoculants. To explore the effects of different carbon sources and microbial inoculants on wheat growth and soil improvement, a two-factor randomized block design experiment was conducted with conventional fertilization as the control (CK). The pot experiment involved co-application of conventional fertilization with different organic materials (wheat straw (WS), maize straw (MS), and biochar (BC)) and various concentrations of microbial inoculant (0, 2.50, 5.00, 7.50, and 10.00 ml per pot). The results showed that compared to CK, the total nitrogen, available phosphorus, and shoot total nitrogen content in wheat were significantly increased by 65.48%, 34.17%, and 61.51%, respectively, under the BC3 treatment (conventional fertilizer + 31.61 g of biochar + 5.00 ml of bacillus subtilis bacillus). The available potassium, phosphorus, potassium, and bacterial count in roots were significantly increased by 121.50%, 68.60%, 101.89%, and 266.27%, respectively, under the BC5 treatment (conventional fertilizer + 31.61 g of biochar + 10.00 ml of bacillus subtilis bacterial agent). According to the effectiveness results of different combinations, it was found that BC3 treatment achieved the highest score. In addition, the results of structural equation modeling indicated that different carbon sources and microbial inoculants formulations indirectly affected wheat growth by regulating the soil microbial community and the soil physiochemical properties. In conclusion, biochar with microbial inoculants was found to be the most effective in enhancing wheat growth and synergistically improving soil physiochemical properties.