Article Review: Regenerative almond production systems improve soil health, biodiversity, and profit.
Research team: Tommy Fenster, Patricia Oikawa, and Jonathan Lundgren.Recently, there has been a lot of interest in regenerative agriculture. Regenerative agriculture is a farming method that integrates practices that conserve and rehabilitate the farming ecosystem. It focuses regenerating topsoil, increasing biodiversity, improving water cycle, and enhancing ecosystem services. There is not one “regenerative practice,” but rather a combination of sustainable and organic practices.
Within almonds, there has been little work research done to understand regenerative agriculture. Most alternative efforts in growing almonds have been mostly focused on organic production (aka biological production). Commercially, there is very little organic almond production. These farms often have integrated regenerative practices into their operations. Regenerative practices tend to focus on removing synthetic agrichemicals, planting cover crops, integrating livestock, maintaining non-crop habitat for beneficial insects, and using composts and water-soluble compost blends (i.e. compost teas). It is important to note that nearly all organic orchards follow some of the regenerative practices, and only some conventional blocks integrate more than 1-2 practices.
To evaluate regenerative system, a comparison between conventional and organic-regenerative orchards was done in the Central Valley of California. This work was recently published in an article titled “Regenerative almond production systems improve soil health, biodiversity, and profit” (Fenster, et al, 2021). This article compared 8 organic and regenerative orchards to 8 conventional orchards over a two-year period. They utilized grower surveys and in-field studies to evaluate these systems. Variables measured include: soil quality (nutrients and biological activity), water infiltration rates, invertebrate communities, plant communities, pest damage, almond kernel nutrient analysis, and an economic analysis of the farm operations.
Orchards selected for the studies were paired within a general location. Paired orchards included organic/regenerative vs a conventional block. These orchards were then scored on a regenerative matrix that included the practices highlighted above (hedgerows, removal of synthetic nitrogen and chemicals, no- till, grazing, etc.). Soils were sampled from the aisles between trees and from the dripline within each orchard. Ecosystem surveys were also conducted on the presence of insects and soil invertebrates. Growers of these fields were also surveyed.
When the soils were analyzed and statistical analysis was performed, the research team found differences in the soil characteristic analyzed between the pairs. They found that the regenerative/organic farms had higher total soil carbon, soil organic matter, total soil nitrogen, total soil phosphorous, calcium, and sulfur. Regenerative/organic blocks also had higher soil health scores, as well as total microbial biomass, total bacterial biomass, more Gram+ bacteria and actinomycetes. Water infiltration was significantly higher within regenerative orchards – with water infiltrating 6 times faster than within conventional orchards. Regenerative/organic orchards also had higher plant, insect, and soil-invertebrate biodiversity. Pest pressures, however, were similar across the farms, and there were no valued differences between kernels sampled from the treatments. Even of more interest was that the organic/regenerative orchards were reported to yield similarly to organic orchards and have twice as profitability of conventional blocks.When reading this paper, I felt it was a bit too good to be true. When evaluating the orchards selected, the were paired well and canopy coverage was about the same when I subjectively rated them using Google Earth. There may have been a slight bias towards larger canopied Regenerative/Organic orchards. When evaluating the methods and specifics of the varied in-field analysis, they seem to be within academic standards and met general peer reviewed rigor.
There were a few interesting points that I thought the paper failed to highlight. One was that soil P levels was were too high within regenerative orchards. The levels present within the regenerative orchards would provide significant run-off risk and water pollution. The second was that the calcium:magnesium ratio was higher within the regenerative blocks (2.13 v/s 1.88 in conventional). This would have a strong influence on infiltration rates within these fields. The higher ratio – just like the high phosphorus levels- is most likely due to increased calcium applications via compost.
There were some aspects of the paper that I felt were left-out which could have helped describe the differences observed. The paper could have also included additional information about the orchards that would help the reader better understand the differences observed. It would be nice to know the age of the orchards, the irrigation system, and source of water. All of these could potentially describe yield differences reported. For example, I know that two of the organic/regenerative blocks within the study use well water that is very high in nitrate-nitrogen. This provides the needed nitrogen to maintain high yields.
The major issues with the paper, however, mostly revolved around the economic analysis and yield reporting. This data was sourced by grower surveys with no on-site field verification. There is an inherent bias in self-reporting, which often leads to higher reported yields with lower operational costs. Furthermore, many operations fail to account for the true costs of practices conducted on farm. Depreciation of equipment and own-labor is often not accurately accounted for. I have realized one important point about surveys through my 10+ years as a UC Farm Advisor– often people will tell you what they think they should be doing rather than what they are doing (By the way, I am personally guilty of this as well).
This all leads to a very confusing and messy economic analysis. First, total operational expenses were published to be $1,376/acre ($3402/ha) and $1,009/acre ($2494/ha) for the Organic/Regenerative and Conventional orchards, respectively. These numbers are way too low to be true production numbers. An inquiry to the authors indicated that these differences of the sum only included the reported values from the survey – not the true operational expenses. I don’t see how that can be viewed as true costs. This makes the analysis very hard to believe.
Lastly, prices were reported to be $4.44/lb and $1.68/lb for the organic/regenerative and conventional orchards respectively. Although the conventional prices make sense, the organic prices in their report are much higher than the organic prices in the open marketplace. This higher price was due to the direct sales of almonds to clients, who often pay a premium for the product. Cost of goods sold, market development, and time spent shipping were not accounted for in this price.
This paper would have been better if they had just excluded the economic reporting. I felt this was a deliberate research question that was not thoroughly explored enough to provide a true answer. On a better note, the observed differences in soil health and ecosystem diversity were the backbone of the paper. These findings are an important contribution to the discussion of farming methods.