Can Intensive Rotational Grazing in combination with Indigenous Microorganism Application
improve soil condition (i.e., soil carbon, minerals, and microbial life)?
Half of the world’s topsoil has been lost in the last 150 years.1
The situation is becoming so
severe that some experts believe that we will run out of topsoil in 60 years.2
Overgrazing livestock has been identified as one of the main contributors to soil degradation
and topsoil loss.1
Static state or minimal rotation grazing of domestic grazing animals results in
compaction of soil, loss of cover, and topsoil erosion.3
On the other hand, removing wild, migratory
grazing animals from rangelands has proven deleterious to ecosystems.4
Thus, the question is: does
overgrazing and soil loss arise from the presence of grazing animals or does it happen due to
Our study aims to determine if soil condition can be improved by Intensive Rotational Grazing
(IRG) in combination with Indigenous Microorganisms (IMO) cultivated by Korean Natural Farming
methods. The treatment groups are the control (rested pasture/no treatment) vs. IRG Pasture
(experimental groups: sheep alone; chickens alone; sheep + chickens; sheep + chickens + IMO).
Parameters measured are soil organic carbon, minerals and microbiological activity. Sheep body
condition score and parasite load (FAMACHA and fecal float) will be measured by a certified
veterinarian to assure method is not at expense of animal health. All data will be collected at the start (t
= 0) and end of the experiment (t = 1 year). Data will be analyzed across experimental groups
(ANOVA) and between times (t-test). Presentation/demonstration will be given at the two largest
Farmer’s Union chapters on the island. Outreach in the form of flyers, social media, and letters will be
done one month in advance to provide ample public information about the presentation.
January 2019 Progress Update:
Mid March 2018:
After being selected for funding, photopoints were set (Figure 1 & 2). The first Facebook announcement regarding the experiment was posted to the Graze & Sprout Farm Page. The image was an interactive panoramic photo of the first photopoint at the top of the property. This photo is interactive and shows/introduces the audience to our Intensive Rotational Grazing (IRG) System. The next related post was a video of the chickens grazing the grass and getting a little treat of cauliflower from the garden. The second post was a video of chickens grazing and was a huge hit with more than 1,800 people reached. Posts continue more than once monthly until October. We were a bit lax during the holidays, but will pick back up.
End of April 2018:
We received grant funds. Materials were also ordered for sampling, research tools, and fencing materials.
Scheduled meeting with the vet (Christy Balcomb). Dr. Balcomb collected data (FAMACHA, Body Condition Scores (BSC) and Fecal Test) on seven (7) sheep prior beginning the experiment. The BCS is based on an scale of 1-5 and is defined: (1) 20% or more underweight; (2) 10% underweight; (3) Ideal, unless pregnant or nursing; (4) Ideal if pregnant or nursing; (5) 20% Overweight. Our sheep scored an average of 3.21 on a 5 point scale (Figure 4). A score of between 3-4 on the BCS is ideal for sheep.
FAMACHA score were also taken. FAMACHA Score uses eyelid color as an indicator of anemia and parasite load. The lighter/more pale the eyelid color the more anemic the animal and the more likely the animal has the blood-feeding parasite barberpole worm. The FAMACHA Scoring System is defined: (1) Optimal, no dewormer needed; (2) Acceptable, no dewormer needed; (3) Questionable, dewormer needed if fecal score is high; (4) Dangerous, dose with dewormer; (5) Fatal, dose with dewormer immediately. The average FAMACHA score is 1.74, indicating a very low level of anemia and suggesting a low to absent level of barberpole worm.
Fecal Examination was performed. The Fecal Examination is used to determine parasite load of: (a) strongyles, (b) coccidia, and (c) tapeworm. The parasite levels were low over all, with the exception of two sheep (Cosmo and Mini). Cosmo showed a heavier burden of strongyles and coccidia. Her heavier parasite load is not surprising as she has had issue with digestion and weight gain in the past. She was treated with a chemical dewormer in January of 2018 and recovered rapidly upon treatment. These results suggest that Cosmo may be more predisposed to parasite and digestive issues than the other sheep. Of note, Cosmo suffered a prolapsed anus shortly after this report was written. She had to be put down due to irreparable damage. Mini demonstrated a heavier load of coccidia than any of the other sheep. She will be carefully monitored to make sure her body condition does not suffer. Overall, Dr. Balcomb did rated parasite load as below average, with no need for deworming treatment.
We can conclude that the sheep were in excellent condition at the start of the experiment with ideal BSC scores, excellent FAMACHA scores, and below average worm load counts. We will compare these data at the end of the study to make sure that the animal health is not compromised via the IRG grazing system.
Technical Advisor (Christina “Bena” Pegg) tried to schedule experimental set-up for June-July, but both of us had unexpected travel plans come up in these months and were unable to schedule. We had to postponed the experimental start date from June to August.
While on the Mainland, Bena contacted MidWest Laboratories to clarify some questions around sampling. She also created a more detailed plan for sample collection so we could hit the ground running in August. From this plan, I set up and marked out the Treatment Group locations in the field.
The Facebook announcement was made early in March, soon after our grant received funding. The website domain grazeandsprout.com was purchased and a template was uploaded. However, the template is so large it bogs down the server making it next to impossible to load or edit the site. At this time I have not had the time or resources to figure out how to fix this technical glitch.
The full IRG + IMO program began in the September 2018. Sampling began in late August and finished in early September. Samples cores were taken at a depth of 6 inches. A total of 7 treatment groups were sampled: (1) Mowed control; (2) Rested Pasture; (3) Sheep Alone; (4) Chickens Alone; (5) IMO Alone; (5) Sheep + Chickens; (6) Sheep + Chickens + IMO. For each sample, 5 cores were taken, sifted of any debris, and mixed to form a uniform sample from which about 1 cup of soil was packaged and shipped to MidWest Labs for analysis. Completed data was received in Mid-September.
November 2018: Bena analyzed and complied graphs for Mowed Control vs. Sheep + Chickens. Upon analysis it became apparent that t-test comparison between groups would be ineffective given the amount of data collected. She is currently working to revise analysis to include all treatment groups, but this time using ANOVA statistical analysis to compare all groups at once. Nonetheless, the first comparison between Mowed Control vs. Sheep + Chickens is informative (Figure 8-17).
Total Carbon (TOC), Total Nitrogen (TN), Carbon: Nitrogen ratio (C:N), percent organic matter (%), bulk density (g/cm3) were compared (Figure 8). TOC, TN, CN, OM% were all significantly lower in the Sheep + Chickens group than the Mowed Control/Rested 2.5 years. Nitrates where significantly high in the Sheep + Chickens groups when compared to Mowed Control. Potassium (K) and were significantly increased in Sheep + Chicken group when compared to Mowed control (Figure 9). Magnesium (Mg) and Sodium (Na) were significantly reduced when comparing Sheep + Chicken to Mowed control (Figure 9). Calcium, soil pH, Buffer Index, and Cation Exchange Capacity were significantly increased in Sheep + Chicken when compared to Mowed Control (Figure 10). Sulfur (S) and Copper (Cu) were significantly lower in T5 (sheep + chicken) when compared to C1 (mowed control). CO2 Burst was significantly increased in T5 (Sheep + Chicken) when compared to C1 (mowed control).
Data in Figure 8 is in direct opposition to established data that suggests Carbon increases in the soil when animals (cattle) are grazed in an IRG fashion. A confounding factor may explain this seemingly contradictory data. Some 15-20 years ago, the pasture where all of our treatment groups are was grazed exclusively by a horse without any management for as long as 15 years. Whereas, the sample taken from the Mowed Control/Rested 2.5 years was taken from a part the property that was never grazed by the unmanaged horse. Thus, we may be seeing the long-term effect of unmanaged grazing showing up in our data. To determine if this is true, we will add a another sample group in the pasture that is also mowed for the final round of sampling.
Interestingly, nitrates were significantly increased in Sheep + Chickens zone when compared to Mowed control. This is likely due to an increase in nitrates from the chicken poop. The contradiction of increased nitrates and decreased nitrogen is yet to be determined. Analysis of Minerals and Soluble salts is yet to be completed.
Increase in Calcium in the Sheep + Chicken group is likely explained by the high calcium feed provided to the chickens and the high calcium mineral provided to the sheep. Not all of the calcium is absorbed by the animals and thus, some is deposited onto the field in manure. The increase in calcium on the field likely contributes to the increase in pH as increase calcium ions in the soil helps to displace hydrogen ions and created a more basic soil. The same principle is true for the high Cation Exchange Capacity. Finally, an increase in Microbial Burst suggests that there are more aerobic, respiring organisms in the soil in the Sheep + Chickens zone when compared with the Mowed Control. This supports the theory that animals can increase microbial life in the soil when managed properly.
February 2019: Bena will complete analysis of the data and contact Maui Farmers Union to set up our presentation.
Additional Items to complete:
Supplementation thus far has been limited to 6 bales of hay and trees cut from the outer edge of the pasture. Dumor Sheep Mineral has been provided free choice. This data will be factored into the final calculation for animals per acre. The winter cycle is approximately 80 days and the summer cycle is approximately 45 days. We have completed two deliveries of IMO onto the test plots. Compaction tests need to be completed at the conclusion of the experiment (September). Additionally, slope and aspect need to me measured at this time.
The objectives are to determine if soil benefits are afforded via:
(1) IRG (Sheep or Chickens alone)
(2) Multispecies IRG (Sheep + Chickens)
(3) Multispecies IRG + IMO (Sheep + Chickens + IMO)
when compared to Rested Pasture and through time. Sheep health will be monitored for body
condition and parasite load to assure rotational grazing is not done at the expense of the animal.
Our method of Intensive Rotational Grazing accounts for effects of seasonal variation on grass regrowth cycle. Grazing cycle is targeted at 45 days per rotation in the warm season (April, May, June, July, August, September, October) during rapid regrowth. Animals can re-graze after a shorter rest period because the grass recovers faster than in the cool season. In the cool season (November, December, January, February, March) rotation is slower and takes approximately 70 days per rotation. Mowing occurs in cycle with the grass and seasonality– but is kept much shorter– the cycle is approximately 15 days in the warm season and 30 days in the cool season.
Animals will be grazed in rotation on approximately 0.9 acres of land. Sheep will be grazed within temporary electric fence paddocks. Sheep will be given two paddocks per day at 10am and 2pm. Every three days a line will be set up behind the sheep, so that they cannot backtrack and re-graze. Rotationally grazed chickens will be moved every 3-4 days on Tuesday mornings and Saturday mornings. They will be grazing immediately behind the sheep within a 3-7 day window. Chickens will tighten their rotation for approximately 0.05 acres when sheep graze alone.
The chicken-only treatment group graze in tractors on approximately 0.1 acres of land. Rotation days will be the same as the rotation days of the other chickens (45 and 70) depending on seasonality. Grazing acres per day will also be the same.
The KNF vegetative treatment developed by Hank Young Cho. will be applied 2 weeks after each rotation to allows for regrowth of the forage and foliar uptake of treatment. Given rotation cycle described above– approximately 7 treatments will be applied throughout the year.
Soil samples will be taken as described in Conant et al. 2002. Sample sites will be marked with a fence post (exact location) and via GPS map (PDF Maps Avenza, approximate location). Soil cores will be taken via soil corer. Samples will be taken to a depth of 6 inches. A total of 5 cores will be taken per composite sample. Each core will be divided, sieved to removed rocks and debris, then packaged as composite sample. A total of 5 composite samples per treatment group will be collected at the start of the experiment (t = 0) and at the completion of the experiment (t = 1 year).
Composite samples will be sent to MidWest Labs for analysis. The tests will include: Total Carbon, T:N, Bulk Density and Soil Health Complete assessment which measures numerous minerals (macro and micro), pH, and microbial activity in the soil.
See the initial summary for this information.
Educational & Outreach Activities
To date we have not organized an outreach or educational event. Outreach will be completed at the completion of our 1 year research project.
We have consulted on three grazing projects: one on Oahu and three on Maui. These projects are still in the works. Consultation on Maui and Oahu was performed in November and is on going to integrate rotational grazing into a large scale agricultural system. The second consultation was with a private land owner for management and electric fencing set up for goats, horses, and chickens. The third was for a farmer with sheep and chickens.
We have had three farmers come visit to tour our property and learn more about Intensive Rotational Grazing since we have begun the project. One farmer is from Haiku; one from Makawao; one from Kula. All have sheep and chickens; one also has pigs.
Of the farmers that we have consulted with or invited to see our farm we have 2 working to develop a similar grazing style and 3 that have already successfully implemented it. One has not yet begun to implement, but is still interested.