Development of soil microbial communities for promoting sustainability in agriculture and a global carbon fix

The goals of this research were to explore alternative agriculture management practices in both greenhouse and field trials that do not require the use of synthetic and/or inorganic nutrient amendments but instead would emulate mechanisms operating in natural ecosystems, between plant and Soil Microbial Communities (SMC), for plant nutrient acquisition and growth. Greenhouse plant-growth trials, implementing a progression of soil conditions with increasing soil carbon (C) (C= 0.14% to 5.3%) and associated SMC population with increasing Fungal to Bacterial ratios (F:B) ( from 0.04 to 3.68), promoted a) increased C partitioning into plant shoot and plant fruit partitions (m=4.41, r2=0.99), b) significant quantities of plant photosynthate, 49%-97% of Total System New C (CTSN), partitioned towards increasing soil C c) four times reduction in soil C respiration (CR) as F:B ratios increased, starting with 44% of initial treatment soil C content respired in bacterial-dominant soils (low F:B), to 11% of soil C content respired in higher fertility fungal-dominant soils (Power Regression, r2=0.90; p=0.003). Plant growth trials in fields managed for increased soil C content and enhanced SMC population and structure (increased F:B) demonstrated: a) dry aboveground biomass production rates (g m-2) of ~1,980 g in soils initiating SMC enhancement (soil C=0.87, F:B= 0.80) with observed potentials of 8,450 g in advanced soils (soil C=7.6%, F:B=4.3) b) a 25-times increase in active soil fungal biomass and a ~7.5 times increase in F:B over a 19 month application period to enhance SMC and c) reduced soil C respiration rates, from 1.25 g C m-2 day-1 in low fertility soils (soil C= 0.6%, F:B= 0.25) with only a doubling of respiration rates to 2.5 g C m-2 day-1 in a high-fertility soil with an enhanced SMC (F:B= 4.3) and >7 times more soil C content (soil C= 7.6%). Enhancing SMC population and F:B structure in a 4.5 year agricultural field study promoted annual average capture and storage of 10.27 metric tons soil C ha-1 year -1 while increasing soil macro-, meso- and micro-nutrient availability offering a robust, cost-effective carbon sequestration mechanism within a more productive and long-term sustainable agriculture management approach.