Climate Change

Introduction

For organic carbon to be not prone to atmospheric emission, it has to be in the ground. Photosynthesis is the primary mechanism for atmospheric carbon accumulation and is tightly associated with fixing root derived carbon, down through the soil profiles.
The overall objective here is large scale atmospheric Carbon Dioxide Removal (CDR IPCC). ANZBIG CRI CDR.

If the ETS, Toitū and Overseer were fit for purpose, Farmers would be in a powerful position to implement CDR for a large-scale material reduction to atmospheric CO₂, a genuine offset for fossil fuel emissions, but that would require environmental accountability that is not currently valid.

Photosynthesis is not rocket science, but it is high school science. Most farmers went to high school, some even went to university and studied rocket science.

Current animal production strategies represent a clear conflict of interest with enhanced photosynthesis compromising grassland Net Primary Productivity. Environmental sustainability does not equal commercial sustainability.

Below is a summary of my literature review supporting a three step carbon pathway to the subsoil; two opportunities to interrupt waste biomass carbon pathway to atmosphere, which come together as a plant ready product for immediate root engagement, to contribute to enhanced photosynthesis “window of opportunity” and drive a carbon pathway to the subsoil for large scale CDR.
It is hard to get better answers if we do not ask better questions.

Pyro / Bio CDR discussion document is a literature review showing that we have two good options for not only interrupting the biomass carbon pathway to atmosphere, but also mitigating chemical and organic pollution due to intensive food and fiber production.

Pyro Carbonisation of nutrient poor biomass (wood chip) and wood derived product (paper and cardboard) does look and sound like rocket science and a recipe for burnt fingers and eyebrows. However, the residual product is resistant to becoming atmospheric with a half life of hundreds of years, for which we have no comparable alternative, but that environmental feature gets no commercial ETS value or recognition.

1. Pyro CDR literature review

• Illustrations showing emission to atmosphere time scales for biomass Vs biochar.
• Increasing temperature increases the volatile yield, porous capacity and half life, but reduces the residual yield.  1, 2 .
• Illustrations showing biochar soil migration behavior and resulting soil emissions. 3, 4, 23, 34, 35, 36 .
• Increasing biochar pore capacity can absorb and release plant available nutrient,    facilitates microbial colonization for enhanced rhizosphere zone of activity. 3, 4 .
• Fresh bio char is nutrient sterile, application to soil can be disruptive to plant available nutrient. 5, 6, 7 .
• Adding fresh bio char to a nutrient dense food and animal waste composting process, promoting thermophilic compost process and microbial colonization resulting in a more nutrient dynamic product. 7, 22, 25 .
• Waste stream feed stocks are meaningful Waste to Energy (WTE) and CDR mitigation. 8 .
• This is an ideal technique for high calorific, difficult to combust waste stream feed stocks like plastic, tyres and textiles but the residual is not biochar. I use the term biochar where the literature says biochar, but otherwise, I will refer to the residual product as Pyrolitic Carbon expressed as Py C.
• Co firing those feed stocks with wood waste increases residual yield and porous quality indicators at lower temperature via the secondary cracking effect. 15, 16 .

2. Bio CDR literature review

Bio compost process is not rocket science, but it is common garden variety high school science.

• Traditional field windrow composting works well for green waste but is more problematic in more nutrient dense food and animal waste. 9 .
• Maintaining aerobic process in nutrient dense biomass is more challenging because the increased oxygen demand and reduced porosity will very quickly become anaerobic at the center of the mass. Reduced thermophilic process will result in more sub thermophilic gradient zones that can facilitate pathogen development, odorous emissions and require long maturation phase to overcome incomplete process. 12, 24,  27 .
• Thermophilic maturity producing a stable product not prone to secondary fermentation and ongoing odorous and GHG damaging emission. 10, 7, 26 .
• Turning of field windrow mass to facilitate air permeability to the core region causes a significant loss to the thermophilic inertia. 13, 14 .
• In vessel Rotary Drum Reactor (RDR) can maintain extended thermophilic process for reduced ongoing and problematic emission. 10, 28 .
• Extended thermophilic process will ensure good pathogen control, mitigate Persistent Organic Pollutants (POPs) such as in pork and poultry effluent, antibiotics and antimicrobials as in the active ingredients in personal hygiene, cleaning and sanitisers. 18, 19, 20 .
• Maintaining thermophilic process for extended period throughout the entire mass must be a priority where increased challenge for intensive organic process exists.
• Bacillus subtilis is the dominant microbe in the thermophilic breakdown process and is a common Plant Growth Promoting Rhyzobacteria (PGPR) which will be equally important to the breakdown of dead soil organic matter for nutrient recycling as a result of enhanced below ground tissue turnover. 21 .
• The product of this co process is a meaningful interruption to the waste biomass carbon pathway to atmosphere and is plant ready for immediate root engagement. 22, 29 .

3. Grassland Carbon Pathway to the subsoil

If intensive grassland management is not your passion, Do not go there!!! It is not rocket science, but it is grass roots high school science. The grassland CDR Doc shows just the pictures.

The grassland literature review documents,

• Long term grassland Rate of Growth record illustrating the origin of grassland under and over utilisation problem at all the wrong times leading to a degenerative grassland trend. 40, 41, 37, 45 .
• Two long term grassland studies documenting increasing SOC with increasing species diversity and there were no animals involved. 42, 43 .
• Enhanced photosynthesis, with early interruption to reproductive maturity increased Below Ground Biomass Net Primary Productivity (BGBNPP) over all grazing defoliation timing and intensity options contributing to species diversity and diversity in Microbial Associated Soil Organic Carbon (MASOC) as documented in the above two long term grassland studies. 44, 45 .
• Exudates production peaks with peak plant photosynthesis nutrient at the onset of reproductive maturity, and then goes into rapid decline at seed set and senescent tissue development. 45 .
• Defining the function of rhizosphere zone of activity is important to understanding the function of the fine root hairs to increasing the surface area for exudate production. 46 .
• A list of studies and study reviews documenting root exudates contribution to rhizosphere input organic carbon into the soil accounted for up to 40% of the carbon fixed by photosynthesis with increased microbial activity to breakdown dead soil organic matter by up to 380% for nutrient cycling. 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 .
• Increased below ground biomass is dependent on photosynthesis from above ground vegetative cover for increasing rhizodeposition. 60, 61, 62, 63, .
• Species diversity driving microbial diversity is central to increasing deep subsoil Soil Organic matter (SOM) and MASOC 64, 65, 75 .
• Increasing Water Use Efficiency (WUE) is a driver of microbial diversity and Carbon Use Efficiency (CUE) 29, 66, 71 .
• SOM and grazing management are big predictors of increasing or decreasing WUE and CUE. 44, 48, 49, 51, 65, 77, 78, 79, 76 .
• Species diversity drives microbial diversity producing increased dissolved organic matter converting organic matter of high molecular weight to low molecular weight dissolved organic matter for downward transport quantified at 3.6m deep into the subsoil and microbial stabilised. 29, 73, 74, 76 .
• The bit that is missing from most of the above studies is a focus on the primary driver of the downward transport of dissolved organic matter, that being green leaf area for photosynthesis “window of opportunity”.
• While droughts are normal, intermittent plant available moisture stress is more normal. 40, Animal production represents a serious conflict of interest to grassland NPP under all but a “No Drought” sequence. 41, 44, 45 .
• FAO 2023 Global assessment of grassland SOC highlights that current grassland management trends are leading to SOC losses (Ratten Lal (2018) and fits with the observations from my grassland photos.
• An extended period of Zero Grazing with Intensive Defoliation at Stem Elongation (ZG/ID@SE) will capture an enhanced photosynthesis “window of opportunity”
• The grassland photos show that enhanced photosynthesis in our traditional grasslands (read; default species dominant) could achieve increased above and below ground biomass NPP by a factor of two or more in the first season.
• If the ETS was fit for purpose, farmers would be in a powerful position to implement[- a speedy, widespread introduction of grassland CDR.
• The animals eat the grass.
• We eat the animals and carbonize the outcome. The perfect circular economy.
• Mono culture pine tree plantations do not achieve the above diversity objectives, SOC accumulation is terminal at plantation harvest. A meta analysis of hundreds of forest harvest studies from around the world found general agreement with SOC losses in the sub soils for prolonged periods. 70 .

Conclusion

The objective is to validate and quantify the Carbon Dioxide Removal (CDR) opportunity.

Effectively, we now have a four step procedure because much of the increased bioactivity retained in the Py C Co-compost product, can be better captured in association with ZG/ID@SE. In any other crop or horticultural application, it will be more exposed and more prone to atmospheric emission.

1.  Pyro carbonisation (PyC) of nutrient poor biomass (wood waste). Say 300kg  of carbon stable residual yield / T wood chip feedstock. 1 .
2.  Bio in-vessel co-process of PyC with nutrient dense biomass (food and animal waste) Say capture volatile nutrient upto 40% emission reduction per t of bulk biomass. 7, 22, 26 .
3.  In the two long term grassland studies, there was no focus enhanced photosynthesis. Just species richness and SOC accumulation. In study 42, they found a 27% increase over nine years. In study 43, observations ranged from 88% to 253% in years 13 – 22 because the site had been so degraded.
4.  Quantifying the carbon advantage of the Py C Co compost product is a bit speculative because I cant find any in-vessel RDR studies that used biochar. There are a number of static in-vessel studies that incorporate biochar but their recordings show some evidence of some incomplete, secondary fermentation in the thermophilic stage, which would have been more complete in an RDR system. Studies 7, 22, 26, show that the emission retentions are not huge but they are the emissions that are most environmentally damaging and problematic (odorous). The nutrient retention will be the most valuable when displacing chemical nutrient. Surface application of chemical nutrient leads to reduced Below Ground Biomass Net Primary Productivity, facilitating excess nutrient pathway into the surrounding environment. 48, 49, 50, 51, Organic nutrient contributes to ecosystem functioning of the carbon pathway to the subsoil, for which there is no ETS recognition.

It’s time for farmers to take action and turn the NZ ETS into a tool that works for both sustainability and profitability.