Garden

Sulfur application for organic blueberries

Well, I didn’t do myself any favors with my poor tracking of soil pH before planting the blueberries. Between the clay soils and overestimation of the buffering effect of decaying organic matter placed into raised beds, my soils were slightly alkaline at the time of planting in the spring. With fall approaching, it was time to apply sulfur while the soil microbes are still active.

Sulfur is not biologically active as its approval for organic uses may insinuate, but it is literally just an element from the periodic table. It is mined and shipped out in its pure form (if you are lucky enough to find pure sulfur) or in my case, cut with 10% inert fillers.

Now it is time to calculate the application rates which I have discussed before. Below are the tables from that discussion. Ohio State University Extension is the source of the Table 1 while Table 2 is the same but with my calculations converting the application rates from pounds of sulfur per acre to pounds of sulfur per 1000 square feet.

 

Table 1. Rates of elemental sulfur required to decrease soil pH to a depth of 6 inches.
Desired change in pH Application rate based on soil texture1
Sand Silt loam Clay
———————– lb S/A ———————-
8.5 to 6.5 370 730 1460
8.0 to 6.5 340 670 1340
7.5 to 6.5 300 600 1200
7.0 to 6.5 180 360 720
8.5 to 5.5 830 1660 3310
8.0 to 5.5 800 1600 3190
7.5 to 5.5 760 1530 3050
7.0 to 5.5 640 1290 2580
1 Assumptions—cation exchange capacity of the sandy loam, silt loam, and clay soil are 5, 10, and 20 meq/100 g, respectively; soils are not calcareous.

 

Table 2. Rates of elemental sulfur required to decrease soil pH to a depth of 6 inches.
Desired change in pH Application rate based on soil texture1
Sand Silt loam Clay
———————– lb S/1000 sq. ft ———————-
8.5 to 6.5 8.5 16.8 33.5
8.0 to 6.5 7.8 15.4 30.8
7.5 to 6.5 6.9 13.8 27.5
7.0 to 6.5 4.1 8.3 16.5
8.5 to 5.5 19.1 38.1 76.0
8.0 to 5.5 18.4 36.7 73.2
7.5 to 5.5 17.5 35.1 70
7.0 to 5.5 14.7 29.6 59.2
1 Assumptions—cation exchange capacity of the sandy loam, silt loam, and clay soil are 5, 10, and 20 meq/100 g, respectively; soils are not calcareous.

I’ve brought my blueberry beds from 8.6 to just below 7 with other efforts this year. For that 120 square foot bed, the calculations are as follows:

[Application rate for clay soils to lower pH from 7 to 5.5] * [Area of blueberry bed] / [Area of application rate]

[59.2 pounds] * [120 square feet] / [ 1000 square feet] = 7.1 pounds

Then for the remaining unplanted bed around 8.5 pH:

[Application rate for clay soils to lower pH from 8.5 to 5.5] * [Area of blueberry bed] / [Area of application rate]

[76 pounds] * [120 square feet] / [ 1000 square feet] = 9.1 pounds

So, 16.2 pounds total.

The process:

Buy agricultural sulfur. It was $22/50 pounds at my local feed store.

Weight out the amount needed from the above calculations

Apply sulfur

Give the soil microbes a few months to digest the sulfur and lower the pH

The last picture shows the sulfur on top of the mulch, spread lightly around plants and their active roots while applied more heavily in the spaces between plants, which is only done by necessity. In the unplanted blueberry bed the sulfur was applied evenly to bare soil then covered by mulch.

From this point on, test the soil every year or every other year. Repeat the above process as needed!

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Garden

My strategy for acidifying soils

In November, my soils tested near a pH of 8 due to the limestone parent and its alkaline calcium contributions. I figured that laying down partially composted horse manure with its pine bedding, mulching it, and letting it compost for another 6 months would help buffer the pH into more manageable levels. Knowing that the blueberry bushes were set to arrive later in the week, I used my quick and imprecise soil kit:

wpid-img_20150512_142142.jpg

Uh oh!

It is apparent that more action is required.

What acidifying soils actually does:

For some reason landscape designers absolutely love putting Pin Oaks in the soil islands in parking lots. No consideration is given to the requirement of these trees to grow in low pH soils. As a result, the trees can’t obtain iron through its roots and wind up chlorotic, or yellowing sick leaves year round. This is the same condition that blueberries will face in too alkaline of soil.

Remember anions and cations from high school chemistry? I’ll spare the most gruesome of details regarding what is going on in soils with varying pH. An alkaline soil is high in cations like calcium or magnesium effectively ties up necessary nutrients in soil like iron due to a low anion exchange capacity.

Further exacerbating the iron uptake issues is that iron is immobile meaning that within a plant, iron cannot be moved from old growth to new growth. The iron requirement in every bit of growth of new leaves, fruit, buds etc. must come from the soils. That is why pH is such a big deal with plants like blueberries!

Acidifying soil strategies:

Attempts to acidify soils can be broken into two categories: Temporary and Slightly Less Temporary. Biologically healthy and active soils have tremendous buffering capabilities in regards to pH. Whatever the motivation to grow a plant like blueberries in alkaline soils like I am doing, the gardener needs to understand that the soil will need constant maintenance to maintain a low pH.

Slightly less temporary acidification means

Slow release soil amendments will release acid as the soil microbes process the parent material of the amendment. The only organically-approved material here is elemental sulfur. While certainly not biologically organic as one would intuitively assume, it still gets organic certification because is is nothing more than a basic element off the periodic table that is found in soils. Application rate depends on the current pH and the structure of the soil. The below table provides a guide with units of pounds per acre. The table below contains the figures once I converted to pounds per 1000 square feet (source):

 

Table 1. Rates of elemental sulfur required to decrease soil pH to a depth of 6 inches.
Desired change in pH Application rate based on soil texture1
Sand Silt loam Clay
———————– lb S/A ———————-
8.5 to 6.5 370 730 1460
8.0 to 6.5 340 670 1340
7.5 to 6.5 300 600 1200
7.0 to 6.5 180 360 720
8.5 to 5.5 830 1660 3310
8.0 to 5.5 800 1600 3190
7.5 to 5.5 760 1530 3050
7.0 to 5.5 640 1290 2580
1 Assumptions—cation exchange capacity of the sandy loam, silt loam, and clay soil are 5, 10, and 20 meq/100 g, respectively; soils are not calcareous.

 

Table 1. Rates of elemental sulfur required to decrease soil pH to a depth of 6 inches.
Desired change in pH Application rate based on soil texture1
Sand Silt loam Clay
———————– lb S/1000 sq. ft ———————-
8.5 to 6.5 8.5 16.8 33.5
8.0 to 6.5 7.8 15.4 30.8
7.5 to 6.5 6.9 13.8 27.5
7.0 to 6.5 4.1 8.3 16.5
8.5 to 5.5 19.1 38.1 76.0
8.0 to 5.5 18.4 36.7 73.2
7.5 to 5.5 17.5 35.1 70
7.0 to 5.5 14.7 29.6 59.2
1 Assumptions—cation exchange capacity of the sandy loam, silt loam, and clay soil are 5, 10, and 20 meq/100 g, respectively; soils are not calcareous.

 

 

As sulfur takes months to have an effect of soil pH, I regret not applying it in November with the installation of the compost. I did rent a tiller and worked 8 pounds into my 80 square foot blueberry bed. I will continue to topdress with elemental sulfur (under the mulch layer). Now I’ll have to work slowly and carefully with the living plants using temporary means while the sulfur goes to work.

Peat moss is another amendment that has been proven to significantly boost blueberry yields. Personally, I don’t think peat moss deserves a place in horticulture as it is a not renewable resource and is extracted from fragile ecosystems. Here is a good article on the subject.

Temporary acidification means

Acidifying fertilizers are one method to maintain soil pH. As there is a large livestock feedmill nearby, I use 50+ pounds sacks of cottonseed meal ($12) as a fertilizer that both provides nitrogen and acidifies soil as it breaks down. It is pelletized which I initially did not like, but after the first rain since applying 200 pounds of it, the pellets explode in volume and hold quite a bit of moisture.

Acidic irrigation is another part of my strategy. I use 2 tablespoons of the cheap distilled white vinegar per gallon of water to irrigate the root zones. I use a much more aggressive rate to apply between plants where no roots yet exist. I repeat this weekly as vinegar only temporarily ties up calcium! Oak tea is an experiment I am currently trying to find a more biological approach than distilled vinegar.

Acidic mulching: mulching materials like pine straw/needles have long been recommended to help acidify soils. While acidifying soils has tossed some obstacles to my biological approach to raising food crops, I still want to mulch in a manner that promotes mycorrhizal fungal dominance that all woody species need. Therefore I mulch with shredded wood from tree tops but apply elemental sulfur below the mulch.

 

Conclusion

The best time to acidify soil is at least 2-3 months before planting. I missed the boat here and now have that added complications of working with living roots that will be burned by a direct application of strong acid. I hope to be able to gradually lower the pH of the soils before the bushes begin producing berries.

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Bees, Garden

Lets talk about companions, acid and berries

If I had to make the choice of a single fruit to eat for the rest of my life, it would be blueberries. Raspberries are such a close second that I would read the fine print of the agreement to try and loophole them in.

Blueberries need acidic soil. I will have to retest my farm, but I anticipate the karst limestone-heavy area is going to need some amendment. In the raised beds I need a solution that doesn’t involve hauling in chemicals or soil amendments. My solution will be to mulch up many of the cedars that have encroached on the pasture. Every year, I will assist by adding a top mulch of chipped, discarded christmas trees (needles and all). I would like to note that I have not found any studies that convince me that pine mulch is any better the just plain old organic matter in acidifying the soil. In a pinch, I won’t hesitate to use the leave litter from the forest as a soil amendment.

As for companions, the literature prescribes clover to help fix nitrogen or acid-tolerant herbs for pest deterrence.

I’m going to take a different approach here. My perennial blueberry patch will be a sanctuary for the bees. Widely-spaced Rhododendron could provide shade for the plants during the dog days of summer, beautiful flowers in its long blooming season, and potentially psychedelic honey. I’ll probably avoid them in the end, but they are a viable companion. Lewisias flowers enjoy acidic soils and bloom in the late winter providing food for the bees when not much else is available. Strawberries are another delicious potential companion that would provide a living mulch but they have many pest and disease issues. Yarrow flowers have a rich history of natural medicinal use and seem to enrich soil where they grow. Clover is the last plant to consider as a legume that fixes nitrogen for the berries high demand.

Honestly at this point I have no idea what companions I want to plant with the blueberries. I think for now I will plant strawberries as a ground cover with no expectations regarding production while locating the flowering herbs on the boundaries of the rows.

If anyone has any suggestions for acid-tolerant plants that provide human food or nectar for bees, please let me know!

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Cattle, Forestry

Carbon Medium for Nutrient Absorbtion in Compost while Wintering Animals

Follow up to Wintering Animals = Backbone of Soil Building

Capturing all of the nutrient rich excrement from the wintering of animals is going to require a huge amount of carbon. Skills I have gained while studying forestry and the associated graduate projects I assisted will be called upon in order to accumulate the carbon biomass I will require. I’ll write a well-cited post on my sustainable forest management plans once I have finished collecting and amassing my research. The gists of my strategy will be to provide the canopy disturbance necessary to have a healthy, sustainable forest.

Good points were made in Joel Salatin’s book, Folks, This Ain’t Normal. Starting around page 182, Salatin asserts that soil is built and carbon sequestered more efficiently via grasslands opposed to forests. Trees grow very slowly, then die. As they decompose, much of that sequestered carbon is released right back to the atmosphere. Grasslands grow, die and decompose every year; multiple times a year if serviced by grazers and herbivores. However the sequestered carbon in the grasslands us more fully absorbed by the soil and stored in the animal tissue of grazers. Salatin’s assertions seem to be backed up by this study I found.

To minimize the negative impact of forest land on the atmosphere, I plan to eventually harvest the dead, diseased, crooked or otherwise undesirable trees from the forest to make room for subsequent generations of oak and hopefully someday soon, American Chestnut. Despite my minor in forestry, I have a lot more to learn about sustainable harvesting. Fortunately, there are many pioneer trees in the pasture that need removed, and the unmaintained forest has many dead trees that should sustain me for at least a year while I broaden my forestry knowledge.

I will likely invest in a wood chipper to process the farms own biomass to provide the winter bedding. I may also seek out locally discarded christmas trees, shredded paper/cardboard, peanut hulls (suggested by Mr. Salatin in our correspondence) or any other source of easily attainable carbon material.

Note: If you plan to store wood chips on your farm, please be sure to do so in a manner that accounts for the heat generated as they naturally decompose. Limit the height of piles to prevent a fire hazard in your structures and to ensure that the chips dry fully.

 

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Cattle, Garden

Wintering Animals = Backbone of Soil Building

Pulling directly from Joel Salatin’s model at Polyface Farm located in the same valley as my own farmstead, the key to building soil will be through compost.

Have you ever turned onto a country road to be immediately hit by the stench of a chicken house or cow operation? What about seeing a huge manure lagoon, no matter how pretty the tank is dressed up?

Farms that smell are polluting by leaching nutrient-rich animal waste into the atmosphere or ground water. My main issue with industrial farming is that carbon is being pulled from the soil and not replenished whether it is by crop production or animal grazing. The agricultural world is slowly realizing that healthy soil and all of its micro/macro organisms need more than periodic injections of Petroleum-based Nitrogen, Phosphorus and Potassium (NPK) fertilizers. Most of all, soil requires organic matter, not to mention multiple other elements beyond the three provided by surplus explosives after World War I. Did I mention the inventor’s role in producing chemical weapons caused his perfectionist-chemist wife to commit suicide?

Back to my farm operation. The backbone of building soil on my farm is going to be the composting of animal wastes captured during winter in a carbon medium. Joel Salatin accurately refers to it as “A Carbonaceous Diaper”. Each cow will produce up to 100 pounds of nutrient rich waste a day. Thats a lot to capture and I will have to lay down fresh, dry carbon bedding pretty frequently! I will discuss the sourcing of carbon in a future post.

Every time I lay down additional bedding, I will toss in some goodies. Local corn, spent grains from brewing beer, old hay, etc. The cows will tromp down the manure/bedding into a pretty solid manure pack. The anaerobic decomposition process will start building soil while also providing heat for the barn and animals. After the cows head back to the pasture in the late spring, it will be time for the pigs to shine! They will be brought in to root up the compost to find the treats I left them. This process will turn the compost as well as aerate it which turns the decomposition aerobic, completing the process of turning the waste into the highest quality soil possible!

Stay tuned for a post on sourcing the carbon for bedding!

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