In this graph, we compared our sites’ soil pH with their longitude (east-west location).  We found that sites further east out on the plains tend to have higher pH than sites closer to the Front Range foothills and up in the mountains.  This could be due to several things. 
Precipitation is higher in the mountains and foothills than further out on the plains.  Higher rainfall is associated with more acidic soil.  Also, a site’s original parent soil material is more acidic in the mountains and foothills than on the plains.  Furthermore, the pH of irrigation water can change soil pH with repeated applications.  Irrigation water becomes more alkaline as it travels further east away from the mountains, picking up tailwater, salts and minerals.  All this means that the location of a field might determine its soil pH as well as its soil health, since soil pH has a significant effect on soil health. (As pH increases and becomes more alkaline, soil health decreases.)

For each of our 7 crop groups, we calculated their average use of 6 different parameters that effect soil health: days of supplemental irrigation water, days of living cover, tons of organic matter added, number of grazing days, their tillage intensity score, and their soil Ph. 
We then examined those averages to see if we could predict which crop groups would have the lowest and highest soil health scores.  The graphs above show the average soil health practices for all 7 crop groups.  See if you can predict which crop groups will have the best and worst soil health scores, just by looking at their relative rankings on soil health practices.  Remember that you are looking for HIGH water days, HIGH days of living cover, HIGH organic matter inputs and HIGH grazing days, but LOW tillage intensity and LOW soil pH to predict the highest soil health scores. It’s just the opposite for the lowest soil health scores.

Perennial Hay/Alfalfa/Pastures: The Pasture group has the highest average soil health scores of these three crop groups.  Although the Pasture group has lower supplemental water days and lower organic matter added, their very high days of living cover and very high grazing days, along with their very low tillage intensity and lower soil pH seem to more than make up for their water challenges, in terms of soil health.
Commodity Row Crops: The Commodity crop group has the lowest average scores of these three groups.  Although they have done an excellent job of reducing their tillage intensity, that fact alone cannot make up for their high soil pH, lowest days of living cover and lowest organic matter added.  They have only 2/3rds of the water availability as the Commercial Veg/Flower/Fruit group, which explains their lower days of cover crops that often require fall seeding and fall water.  Inter-seeding cover crops aerially or when the main crop is still small are work-arounds but not always practical.  Low commodity prices mean the cost of additional organic matter inputs like compost and manure are hard to justify.
Commercial Veg/Flower/Fruit: The Commercial Veg group has the highest tillage intensity by far, but also triple the organic matter inputs of the other 2 groups.  These huge organic matter inputs, along with their longer water season, greater use of cover crops, and lower soil pH overpower their intense tillage and boost their average soil health scores above the commodity crops’ averages.  Their longer water season means they can plant more fall cover crops and string together succession plantings for a longer growing season.  Their high value vegetables mean that they can afford organic matter input costs and hauling fees.

In the top graph above, 71 sites with both grazing animals and organic matter inputs (OMI) are each represented by a quadruplet of data points connected by a vertical black line (a blue square for 2019, red circle for 2020, green triangle for 2021, and yellow diamond for 2022).  Each square-circle-triangle-diamond-black-line combo represents the Soil Organic Matter (SOM) values for one site for 4 years. According to the literature, SOM is supposed to be quite stable and very difficult to change, and yet we are seeing large swings in individual sites’ SOM data, especially when grazing animals are present or organic matter is imported to the site, as is the case in the top graph above.
We only have 12 sites in our study which have no grazing animals or imported organic matter for 3 or more years.  The second lower graph shows that the variability in SOM values for these 12 sites is much less than for sites with grazing animals or organic matter inputs.

We examined our 28 sites which have the most variability in their soil health scores.  We call these sites our “Swingers”, and they are evenly split between organic and conventional growing methods. 
Over half the “Swinger” sites are pastures with the rest split evenly between home gardens and commercial vegetable sites.  Their most common crop is grass hay with mixed vegetables coming in second. Their average water season is 127 days long.  “Swinger” sites have an average soil health score of 27.6, which is very high, especially for Colorado.  The growers of these “Swinger” sites are all Soiley Award winners or nominees.  They have adopted many soil health practices, as you can see in the following graph.

The lesson here seems to be that no good deed goes unpunished.  It seems that one result of adopting good soil health practices may be a great deal of variability in soil health lab results.  If you see your Haney test results bouncing around a lot, year-to-year, it does not necessarily mean that you are doing anything wrong.  It may mean that you are doing many things right!  We will explore this hypothesis further in coming years as we gather more data.

We sorted our sites into 3 groups and calculated the average variability for each group.  This bar graph shows that the groups which grazed animals or added organic matter to their sites for 2 consecutive years have approximately three times as much variability in their lab results as the group with NO grazing animals and NO organic matter inputs.

This graph shows the soil health practices which our growers could identify upon enrollment in the project, ranked from most to least commonly named.  Every grower could identify at least 5 practices as contributing to soil health, and many could identify far more.  There seemed to be a strong correlation between the soil health practices a grower could identify and the practices they were already using on their land.  It seems that most growers believe they are already improving their soil health.

Three quarters of our growers report making changes to their operations over the first 3 years of the project, as a result of information they have received about soil health. In the 21st century, we expect organizations and sectors to be nimble, able to rapidly adapt to new technologies and turn on a dime like a drone.  However, agriculture is NOT like a nimble drone, but rather is like a huge super tanker, taking an exceedingly long time to turn.  In agriculture, there is usually only one shot per year to try something new, and many reasons why that one shot might or might not work in that year, which then requires more years of testing, tweaking, and retesting.  That is why the CSSHP is a 10 year long project.  

In this graph, the green bars are the soil health scores of the sites that were sampled in the spring, and the orange bars are sites that were sampled in the fall.  The height of the bar shows the site’s soil health score.  Our spring soil samplers had a significantly lower median score than our fall samplers.
This is why it is important to test your soil health at the same time each year.  If you test soil in the spring, then apply a soil amendment and test again in the fall, you won't be able to really tell if the amendment affected your soil’s health.  Any increase in the soil health score may just be due to this seasonal variation we see here.  You must test your soil at the same time each year to really be able to assess changes in soil health.

This table shows that in 2021 only about half of our growers fully understand their soil testing results and use this information to drive management decisions.  The remaining growers prefer a different test, have found an outside advisor to assist them in management decisions, or are challenged to understand their test results.   
We see greater understanding of the confidential individualized year-end reports that we send to all growers.  Our year-end reports show growers how they compare with their peers on 10 important Haney and PLFA soil health indices, and three management practices.  The Year-End report contains more graphics and fewer categories to decipher than soil test results.  It is designed so that a grower can easily see if they fall into the top, middle or bottom of the pack.  This may explain why more growers understand the year-end report than their soil test results.

In 2021, we asked CSSHP growers how we can improve our project.  This table shows that their overwhelming choice was to provide more individual consults with soil health experts, similar to the individual consults which Lance Gunderson provided 19 of our growers in 2020.  Second and third choices are “more presentations from fellow growers” and “help with funding for soil health improvements”.  We have taken their message to heart and are including more of these 3 things in the project

This pie chart shows 47 growers’ answers to the question, “Have you tested your soil before?” A sizeable minority of our growers was unaware of fertility and nutrient balancing issues prior to their participation in our project, so even without confirmed soil health progress, our testing has been valuable for these growers from a fertility and profitability standpoint.

This table shows the areas where we have succeeded and failed in the first 3 years.  We have surpassed our objectives for enrolling new growers, purchasing extra soil health tests, encouraging implementation of new soil health practices, and promoting individual growers as subject-matter experts. However, we have not been successful at strengthening connections between different factions of our agricultural community, nor have growers participated in community outreach events partly due to COVID.

In these 2 graphs, sites were divided into 2 groups: 35 sites with grazing animals and 21 sites without grazing animals on-site at some point during the year. We then graphed each site's 3-years'-worth of soil organic matter data by connecting the 3 years of data from each site with a vertical black line. When the 3-year variability of soil organic matter data is compared between sites with and without grazing animals, sites with grazing animals clearly show more variability in SOM data, year to year.
Grazing animals deposit manure and urine in small exact locations.  If that exact location is sampled one year and then not the next, that could change lab results significantly.

This graph shows the variability we have found in our Soil Organic Matter (SOM) data for 58 sites over the last 3 years. The 58 sites are each represented by a triplet of data points connected by a vertical black line.  Each site’s linked data points include a blue square for SOM in 2019, a red circle for SOM in 2020 and a green triangle for SOM in 2021. 
According to the literature, Soil Organic Matter is supposed to be quite stable and very difficult to change, and yet this graph shows large swings in individual growers` SOM data from year to year.  We have found similar variability in other soil health indices as well.  We are analyzing our data and collection protocols to understand the sources of this variability.  More data from upcoming years will help in this effort.

In this graph, we compare 52 tilled and untilled fields with grazing animals, with 77 tilled and untilled fields without grazing animals.  Our data shows that fields with animals had higher median scores for several soil health indices (brown bars) than fields without animals (blue bars).  Grazing days (number of days animals were in the field) ranged from 3-365 days, with a median number of grazing days of 44. 
While overgrazing can cause soil compaction, erosion and poor soil health, well-managed grazing can have the opposite effect.  Animal excrement recycles plant nutrients, enriching the soil and its microbiome. Well-managed grazing animals have been shown to provide other ecosystem services such as soil stabilization and formation, and increased water infiltration and carbon sequestration.

In this graph, we compare the median scores of 152 tilled fields, with organic matter inputs (brown bars) and without organic matter inputs (blue bars).   This graph shows that tilled fields with added organic matter inputs have higher median scores for soil organic matter (SOM), soil respiration, organic carbon, microbially active carbon, soil health, microbial biomass and fungi-bacterial ratios than tilled fields without organic matter inputs. Our data shows the same to be true for untilled fields, but to a lesser extent.
Organic matter inputs, including composts, manures, and mulches can jump-start the formation of soil organic matter, add microbiology to the soil, and supply macro and micro nutrients. However, continuous inputs can also contribute to soil health challenges, such as excessive phosphorus levels. In our project, “organic matter inputs” only include inputs from “outside” the study field, and don’t include manure deposited by animals grazing in that field or bio-mass generated by crops and cover crops.  It seems that extra organic matter inputs have a larger effect on tilled fields than on pastures.

In this graph, we compare the soil organic matter at 209 tilled sites with the number of days of living cover on the site. The red trend line shows that as days of living cover increase, soil organic matter also increases. 
Living vegetation protects soil from wind and water erosion while also supplying the soil with fresh organic matter and feeding the soil microbiome. Linking together crops and cover crops to maximize days of living cover is a fundamental soil building practice.   Our data shows that with more days of living cover (i.e. more crops and cover crops linked together and less days of bare soil during a calendar year), soil organic matter, organic carbon, microbially active carbon and the percentage of fungi in soil all tend to increase.

23 sites in our study have what is considered excessive phosphorus, with more than 300 pounds per acre of available phosphorus in their soils.  This graph shows the kinds of organic matter inputs applied to our 23 sites with excessive phosphorus. Manure was applied to 57% of sites, compost to 35% of sites, and grazing occurred on 30% of sites.  Known 3-year totals of all organic matter inputs applied to these sites range from 0.75 to 280 tons/acre, with a median 3-year total application of 22 tons/acre. 
Manure and compost are excellent soil amendments to improve a soil’s health, increase soil organic matter, and increase fertility.  The 23 sites with excessive phosphorus all had good to excellent soil health scores, ranging from 7 to 36 with a median score of 17.  These soil health scores show how beneficial manure and compost are for soil health.  However, no good deed goes unpunished, and the downside of frequent large manure and compost applications can be excessive build-up of phosphorus in soils.

This graph shows the phosphorus levels of 147 sites, with each bar representing the phosphorus level of one site.   The green bars are non-farm sites and generally have very low phosphorus.  The red bars are growers using conventional growing methods and fertilizers, and fall mostly in the ideal range. Phosphorus levels for our organic growers are the yellow bars, and are generally quite high into the concerning range. 
Phosphorus is a Goldilocks kind of nutrient.  You don’t want too much OR too little. You want it just right. Plants need it to grow, but too much can pollute downstream waterways and cause plant nutrient deficiencies.  Manure is a go-to fertilizer for our Front Range growers, and because organic farmers cannot use chemical fertilizers, they often apply large amounts of manure to boost their nitrogen levels.  However, manure is also rich in phosphorous, which can build up in soils over time.
Excessive soil phosphorus is a common problem in organic production nation-wide and among CSSHP growers as well. Growers with very high phosphorus levels are advised to switch to low-phosphorus amendments, incorporate legume cover crops to boost nitrogen but not phosphorus, ensure adequate buffer strips along fields to slow and absorb nutrient run-off, and run plant tissue analyses for iron and zinc if deficiencies are suspected.

This bar graph shows that loam soils are uncommon among our tested sites.  Only 15% of our sites have loam or sandy clay loam soils, our two soil types with the highest soil health score medians.  85% of sites are contending with sandy loam, clay loam or clay soils, which are less conducive to microbial life and more difficult to improve.  Sandy soils are porous, and have difficulty holding onto water and nutrients.  Clay soils are dense; roots, water and air have trouble penetrating them.  Soil texture is impossible to change.  However some of its structural problems can be ameliorated by adding large amounts of organic material, which can make clay more porous and sand more water-retentive.