43 min

Microbial Communities for Carbon Sequestration with David Johnson Regenerative Agriculture Podcast

    • Earth Sciences

In this episode of the Regenerative Agriculture Podcast, John interviews Dr. David Johnson, a New Mexico State University research scientist, Adjunct Professor for the College of Agriculture at Chico State, and Faculty Affiliate for the Center for Regenerative Agriculture. His research clearly outlines the importance of managing the ratio between fungal and bacterial populations in the soil for plant productivity and carbon sequestration. During his research on the salinity of manure compost, Dr. Johnson and his wife, Hui-Chun Su, developed the BEAM Soil Compost Bioreactor which develops compost with high fungal populations. John and Dr. Johnson discuss carbon cycling and the capacity of biology to sequester carbon and build soil organic matter. The conversation provides a fascinating look at the role of carbon dioxide in agriculture and the environment, how the ratio of fungal to bacterial populations in the soil are key to carbon cycling, and the methodology growers can employ to actively increase soil organic matter while decreasing costs. 
Carbon Sequestration (00:02:00)
Dr. Johnson explains that high concentrations of carbon dioxide are problematic due to the impact on the climate, increasing the global temperature, rather than the impact of CO2 on plants, which like high concentrations of carbon. Due to those effects, carbon sequestration must be part of sustainable agriculture. John mentions that he has seen organic matter gains in the fields of half a percentage point per year, a very rapid improvement. Dr. Johnson believes that rate is possible, but only with cattle or other grazers in the system. In his experiments based solely on biology, he sees a little over a quarter of a percentage point per year increase in soil organic matter, or 10 tons of carbon per hectare. 
The Microbial Community (00:08:00) 
In order to realize these significant results in building soil organic matter, Dr. Johnson says the microbial community must be balanced. The microbes cycle carbon, improve carbon use efficiency, and create a healthy soil system. Plowing and the use of biocides destroy fungal populations, so those need to be restored in order for soils to function appropriately. John references a slide in one of Dr. Johnson’s presentations comparing fungal to bacterial biomass ratios and the partitioning of the photosynthates. The explanation is based on an experiment with compost made in the BEAM bioreactor, where fungal dominant soils were shown to utilize five times the amount of carbon in the plants than bacterial dominant soils. An average of 11% of carbon captured by a plant goes into the root, shoot, or fruit of the plant in most agricultural systems today, but in a fungal dominant soil, 55% of the captured carbon can be partitioned into the plant rather than into the soil. This can dramatically affect plant productivity and growth. Maximum productivity and carbon capture happen when the fungal to bacterial ratio is one to one, which also causes soil respiration to decrease. There can be increased crop biomass as well as more organic matter in the soil. Dr. Johnson notices that as fungal populations in the soil are restored, farmers are often happier. About 60% of a crop must be left to effectively rebuild the soil even after the soil microbes are in balance, rather than 100% removal. 
Balanced Systems (00:27:00) 
Dr. Johnson explains that having the right microbes is a necessary first step towards building soil health, but is not the complete solution. The compost his team uses as an inoculant has over 2,500 species of bacteria and over 400 species of fungi, archaea, viruses, and more. That is a balanced community of varied microbes. The energy flow and carbon flow is also critical, and the photosynthetic rate must be increased. All of those work together to make a much more efficient, restored system. When the soil biology is in balance, the microbes can make the elemental nutrients available for the plant. That

In this episode of the Regenerative Agriculture Podcast, John interviews Dr. David Johnson, a New Mexico State University research scientist, Adjunct Professor for the College of Agriculture at Chico State, and Faculty Affiliate for the Center for Regenerative Agriculture. His research clearly outlines the importance of managing the ratio between fungal and bacterial populations in the soil for plant productivity and carbon sequestration. During his research on the salinity of manure compost, Dr. Johnson and his wife, Hui-Chun Su, developed the BEAM Soil Compost Bioreactor which develops compost with high fungal populations. John and Dr. Johnson discuss carbon cycling and the capacity of biology to sequester carbon and build soil organic matter. The conversation provides a fascinating look at the role of carbon dioxide in agriculture and the environment, how the ratio of fungal to bacterial populations in the soil are key to carbon cycling, and the methodology growers can employ to actively increase soil organic matter while decreasing costs. 
Carbon Sequestration (00:02:00)
Dr. Johnson explains that high concentrations of carbon dioxide are problematic due to the impact on the climate, increasing the global temperature, rather than the impact of CO2 on plants, which like high concentrations of carbon. Due to those effects, carbon sequestration must be part of sustainable agriculture. John mentions that he has seen organic matter gains in the fields of half a percentage point per year, a very rapid improvement. Dr. Johnson believes that rate is possible, but only with cattle or other grazers in the system. In his experiments based solely on biology, he sees a little over a quarter of a percentage point per year increase in soil organic matter, or 10 tons of carbon per hectare. 
The Microbial Community (00:08:00) 
In order to realize these significant results in building soil organic matter, Dr. Johnson says the microbial community must be balanced. The microbes cycle carbon, improve carbon use efficiency, and create a healthy soil system. Plowing and the use of biocides destroy fungal populations, so those need to be restored in order for soils to function appropriately. John references a slide in one of Dr. Johnson’s presentations comparing fungal to bacterial biomass ratios and the partitioning of the photosynthates. The explanation is based on an experiment with compost made in the BEAM bioreactor, where fungal dominant soils were shown to utilize five times the amount of carbon in the plants than bacterial dominant soils. An average of 11% of carbon captured by a plant goes into the root, shoot, or fruit of the plant in most agricultural systems today, but in a fungal dominant soil, 55% of the captured carbon can be partitioned into the plant rather than into the soil. This can dramatically affect plant productivity and growth. Maximum productivity and carbon capture happen when the fungal to bacterial ratio is one to one, which also causes soil respiration to decrease. There can be increased crop biomass as well as more organic matter in the soil. Dr. Johnson notices that as fungal populations in the soil are restored, farmers are often happier. About 60% of a crop must be left to effectively rebuild the soil even after the soil microbes are in balance, rather than 100% removal. 
Balanced Systems (00:27:00) 
Dr. Johnson explains that having the right microbes is a necessary first step towards building soil health, but is not the complete solution. The compost his team uses as an inoculant has over 2,500 species of bacteria and over 400 species of fungi, archaea, viruses, and more. That is a balanced community of varied microbes. The energy flow and carbon flow is also critical, and the photosynthetic rate must be increased. All of those work together to make a much more efficient, restored system. When the soil biology is in balance, the microbes can make the elemental nutrients available for the plant. That

43 min