The variability we continue to see in our lab results has thrown a great big monkey wrench into our ability to assess progress using only our lab results. However, we can still assess the progress our growers have made in increasing their use of tried-and-true soil health practices, including:

• Increasing their Days of Living Cover
• Increasing their use of Cover Crops
• Decreasing their Tillage Intensity
• Increasing their Organic Matter Inputs

Our growers have made excellent progress incorporating 3 out of 4 of these soil health practices in the last 5 years.

We have 5 years of data on the 51 sites which have been in the project since the very beginning, with data on both their management practices as well as their soil testing results.  The average Days of Living Cover on these 51 sites has increased by 20 days since 2019.  Our growers have increased their Days of Living Cover by increasing their use of cover crops, converting annual crops to perennial systems, and incorporating more fall-planted small grains into their rotations.

Our growers have increased their days of cover crops on average by 25 days/site since 2019.  We examined the 200 sites for which we have cover crop data and found that our growers’ Cover Crop Use has increased for almost all our crop categories including Commercial Veg/Flower/Fruit, Commodity Row Crops, and Home Gardens. 

Two thirds of all our growers have planted cover crops in the last 5 years, with Commercial Vegetable and Commodity growers leading the way.  Only when a rancher inter-seeds a cover into an existing pasture or reseeds an annual field into a perennial crop do we credit a cover crop to that site, so we expect that cover crop use would be low for many of our established Perennial Hay/Alfalfa/Pasture sites.  Dryland grain sites, which depend on 420 days of fallow soil to store enough soil moisture for a biennial small grain crop, avoid cover crops because cover crops can deplete soil moisture.

When we examine just the 51 sites for which we have 5 years of data, we see that our growers have decreased their Tillage Intensity by 17 points over the last 5 years. This is very good news since lower tillage intensity is correlated with better soil health.  We use a Natural Resources Conservation Service soil erosion model to assign a soil disturbance score to all farm operations that compact or disturb soil.  For example, NRCS assigns a single pass with a subsoiler-chisel plow a score of 52.6, a disc harrow gets a score of 11.67, and hay cutting equipment gets a score of 0.15. We total all the scores from each implement used in a field in a calendar year to compute the tillage intensity score for each site.

When we examine the Tillage Intensity of the 191 sites for which we have tillage data and group them into their 5 crop categories, we see that 4 crop groups have made very good progress in reducing their Tillage Intensity, with Commercial Veg/Flower/Fruit sites and Dryland Grains making the most progress.  Perennial Hay/Alfalfa/Pastures have held steady with quite low Tillage Intensity scores.  Home gardens also have low tillage intensity scores, because many of our home gardeners use mostly hand tools, which disturb the soil less and have lower intensity scores.

A majority of all our growers have used organic matter inputs (manure, compost, mulches) on their sites in the last 5 years, with home gardeners leading the way.  We only count the organic matter inputs which are acquired off-site in this analysis.  Manure deposited by grazing animals on-site, or clippings from on-site cover crops, are not counted as organic matter inputs here.  Thus, perennial fields with aftermath grazing often appear to have no organic matter inputs, even though they may have many days of grazing animals depositing manure and urine there.

Organic Matter Input use has decreased by 13T/acre on average since 2019.  When we examine our successive years of data and divide our sites into their different crop categories, we see that only home gardeners have increased their Organic Matter Inputs in the last 5 years.  All other crop categories have seen a sharp decrease in Organic Matter Inputs.  Commercial Veg/Flower/Fruit growers have seen the biggest decrease.  Our growers identified several possible causes for this decrease. 

• An exceptionally wet May-June-July in 2023 meant growers had a hard time planting, cultivating and harvesting between storms.  They may not have wanted to or been able to get additional machinery into soggy fields to spread amendments.
• Fuel and hauling costs for amendments have tripled in recent years, putting amendments out of reach for many growers.  Several have switched to amending with more economical cover crops if they have the water to get them established.
  
• Some growers with excessively high phosphorus levels have decided to forego organic matter inputs and use cover crops instead, to avoid increasing their soil phosphorus to dangerous levels.
  
• Our very tight labor market meant growers struggled all season to fill vacant positions.  They may not have had enough workers to do things like spread amendments. Additionally, our tight labor market has increased labor costs sharply.  This has affected Commercial Veg-Flower/Fruit growers the most as their crop category is the most labor intensive.  Recent high labor costs may have consumed any profit that formerly paid for purchased amendments. 

These 4 graphs show that Home Gardens and Perennial Hay/Alfalfa/Pastures have the most variable soil health scores year-to-year.  Each site’s 3-5 years of soil health scores are represented by a column of 3-5 colored data points connected by a vertical black line (a blue square for 2019, red circle for 2020, green triangle for 2021, yellow diamond for 2022 and aqua diamond for 2023). Each square-circle-triangle-diamond-Blackline combo represents the Soil Health Scores for one site for 3-5 years.  Sites with the most variability have the tallest black lines between their lowest and highest scores.
Last year we showed that large amounts of organic matter inputs and more days of grazing animals increased variability.  This year we have shown that home gardeners apply the highest rates of organic matter to their sites, and we know that grazing animals are usually found in pastures.  It makes sense then that Home Gardens and Perennial Hay/Alfalfa/Pastures would experience the greatest variability in Soil Health Scores.

We continue to see a great deal of variability in our lab results when we compare sites with themselves year-to-year.  We divided our sites into 4 crop categories (Commercial Veg/Flower/Fruit; Commodity Row Crops and Dryland Grains; Home Gardens; and Perennial Hay/Alfalfa/Pastures) and examined each category’s variability.  These 4 graphs show that an examination of past practices can often explain some of the exceptionally big jumps in variability which we see in every crop group.

There are significant differences between our sites with the most variable soil health scores (our Swingers) and our sites with the least variable scores (our Parked sites).  The most significant difference between the 2 groups is that Swinging sites have 3 times the number of average grazing days as Parked sites. While Swinging and Parked sites have the same numbers of sites with grazing animals, Swinging sites have animals grazing on-site for a much longer period of time.  2/3rds of Swinging sites are pastures, and the majority of Swinging sites use conventional growing methods.  Swinging sites also apply an average of 7.5 T/acre of organic matter inputs, almost 50% more than Parked Sites at 5.6 T/ac.  These findings support our 2023 findings that more grazing animals and organic matter inputs increase variability.