Healthy Soils Compost Spread Update

As you know in 2017 we applied for and secured a cost share grant through CDFA for a broad acre compost application on rangelands. This year 2020 was our last year in the program where we applied our final 27 semi truck loads totaling 1,188,000 pounds of compost across 53 acres. This brings us to almost 3.5 million pounds of compost spread over the last three years across SMI.

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So far the most recent soil data has been encouraging. Due to covid the RCD was unable to come out and help run the monitoring tests until late May. Due to the very dry year and the late sampling and covid we ran a triage version of the monitoring where we only sampled 3 out of the 7 treatment plots to one depth (as opposed to two). We also sampled 3 out of the 6 control plots to one depth as well. The data we got back showed our treated plots (3 out of 6) average carbon increased from 2.2% in 2019 to 2.4% in 2020 which is an 11% relative increase. To put that in perspective a ~ .08% overall carbon increase (.15% OM) in the top 6 inches of soil across all grazing lands in California, would result in 89.5 million tonnes of Co2E removed from the atmosphere. California emissions are approximately 457 tonnes per year. 

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This is in contrast to our control plots which were untreated and went from 1.98% carbon to 1.9% carbon on average or a 5% relative decrease. This decrease is in line with the research and observations of soil scientists that we are in contact with in California. This state of deteriorating carbon in annual rangelands in California is the impetus behind the healthy soils program and it is encouraging that the treatments are performing as expected. That being said the real test will be sampling in 2022 after no treatment applied in 2021. The theory is that the 3.5 million pounds we applied initiated a state change to kick the soil life into gear to create a positive feedback loop. So 2022 and beyond will be telling and the real test. But so far….so good!

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