Our soil tests are in. Now to figure out what all of this means, and to improve our soil in our orchard/food forest area. We dug up soil 6″ down in 5 different spots and put a scoop of dirt into a bucket. (clean shovel, clean bucket). I mixed these up, filled up a zip-lock sandwich bag and dropped it off at our local Arkansas extension office. Love their receptionist!
Here is a copy of the results:
Biggest recommendation, add lime, 30 lbs per 1000 sq ft. pH was 5.5 when tested. Next was to add fertilizer 13-13-13 at 15 lbs per 1000 sq ft in the spring. Just those 2 things. Boron came up zero, I have none available for my plants. Hmmm. First thing I checked out.
“Boron promotes maturity with increased set of flowers, fruit, yield and quality. Boron is necessary for nitrogen conversion. Good boron levels make for good disease resistance. Boron is the only micro-nutrient that once corrected will still need to be applied every few years.” Wood Leaf Farm
Several places mentioned how essential Boron was for fruit trees, helps to set fruit, improves disease resistancy. They don’t need a lot, in fact if you give them too much boron, it can “poison” them. How much to add is still the question. I’ve read several places that 2 T for young trees, up to a cup for a mature, apple producing tree is good. Maybe half borax one application and a 2nd application 2-3 weeks later. Some say you only need to add borax once every 3 years or so. I like the idea of dissolving in water and using it around soil of my fruit trees out to the drip line.
Boron deficiencies are often found in acidic soils with high rainfall. Yep that is me.
pH Issues ph looks simple, just add lime or sulfur until you get the desired number. Doesn’t work that way. For one thing, your pH level shifts during the year. Next, you have several layers of soil, and they won’t all have the exact same ph. Plants are smart, they send out roots, seeking out whatever it is they need.
Calcium and magnesium levels play a part in achieving a thriving soil base. Dolomite lime adds both calcium and magnesium. I need both so I can use a certain amount of dolomite lime (the only kind I can find in any local stores). Using formulas found at Wood Leaf Farm:
7 (ECEC) x 60% (Ca sandy soil) x 400 = 1680
1680 – 920 (available Ca) = 760 lb Ca per acre needed
7 (ECEC) x 15% (Mg) x 240= 252
252 – 118 (available Mg) = 134 lb per acre needed
Seems like a lot to add of these two nutrients. Now if I’m adding 30 lbs of dolomite lime (1 cup equals 1 lb) per 1,000 sq ft and 43560 sq ft per acre, that would be approximately 1305 lb of lime per acre. Dolomite lime is 11% magnesium and 25% calcium according to one source. That acre would be getting 326 lb of lime (well below the 760 needed) and 143 lb of magnesium. That wouldn’t be enough calcium but all the magnesium I’d need. Not too much as I figured 15% when sandy soil can use up to 20%.
We could still use more calcium, and the pH could use more adjusting. This may be enough for now, test again in a year, see how my plants do. With healthy, happy fruit producing trees (not there yet) I wouldn’t worry about the numbers. I’ll keep an eye open for Calcium sources.
My plan, feel free to add suggestions: Over the next month to prune trees, add lime (possibly less than the 30 lb per sq ft recommended plus wood ash), add small amount of borax in water over drip line area.
Cover with compost and wood chips, leaves and/or other mulch.
Early, early spring add more nutrients, probably with foliar spray using recommendations from The Holistic Orchard Book . Blood, bone meal and green sand. More borax in the spray. Still to do, make my fruit trees their own compost piles, adding some wood ash. I may even sprinkle some wood ash around my trees. It will help raise the pH, add calcium and potassium. Our potassium levels are very low, so adding more is a bonus.
Soil Resource Links
Balancing Soil Using Organic Minerals Great resource from Wood Leaf Farm, even gives you a formula for calculating how much calcium and magnesium.
Boron in Fruit Trees and Nuts Boron charts
The Soil Test Report Understanding University of Arkansas Soil Test Reports
Michigan State University Soil Calculator Add your soil test numbers and it spits out how much of what to add.