# Soil Test Results - Hard Clay



## LeeB (Jul 1, 2019)

Here are my soil test results. The sample consisted of many core samples to 3" depth, with the top 1/2" removed.



Previous tests showed my soil pH in the mid 5's, I've since added lime at a rate of 1.2 tons per acre, which seems to have worked well.

My soil is a very hard clay, when it's dry it's like concrete. I'm doing twice a year aeration. No irrigation here. Two year old lawn. Having trouble getting a consistent green color throughout the lawn, and some areas grow much faster than others (comparing same species of grass within those areas). The sample is an average of the whole lawn, but it's very likely that the individual samples vary significantly between the good and bad areas due to different soils being mixed. Mostly ryegrass, some blue, and more fine fescue in the shady areas.

I've fertilized a couple times so far this year, I'm at about 2 lbs N and 1 lb K per 1k cumulatively.

Let's see what others have to say, especially on the micros.


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## Ridgerunner (May 16, 2017)

The micro nutrients are low, although not necessarily deficient as they are near borderline sufficiency levels. Turf grasses are very efficient at harvesting nutrients and seldom are micros deficient. However, a number of soil dynamics (high calcium or phosphorous levels, for instance) can impede plant availability of nutrients even at levels that might otherwise be considered sufficient, particularly micros, that can create a deficiency. Low reported levels do reflect an increased probability that a deficiency might exist. A tissue test would be required to identify any micro deficiencies. There are a few granular products that contain maintenance levels of some or all of the micros and there are also foliar/liquid products that can help remedy this in the short term. For example see products offered by Site One, www.plantfoodco.com, www.domyown.com, Core Agri, Nutrient Ag Solutions, etc.
Your soil CEC is in the 10-12 range, That's not indicative of a clay soil. That's not to say your soil doesn't contain clay or isn't hard when dry. Hard (tight) soils can impede root growth. High Mg levels and low Ca: Mg ratios can contribute to a "tight" soil. Your soil Ca:Mg ratio is 2.5:1. That could be a contributing cause of some of your soil tilth issues. The low OM is also a factor.


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## LeeB (Jul 1, 2019)

Just an update with what I actually ended up doing, partly for my records.

Had a lot of problems with orange lawn rust fungus in late July and August, so part of my focus is to improve disease resistance. My frontline strategy was to push some growth with targeted Milorganite during hot weather and a bit of urea before rainfalls. I need to find a better slow release N source that will last through the hot months that doesn't cost me a fortune or require dozens of bags for an app.

Potassium was adequate, but I wanted to increase to an optimal 150 ppm for hardiness, so I did a potash application (0-0-60) at a rate of 2.5 lb per k. My soluble salts are very low and I did it before a big 1"+ rainfall so there were no adverse effects.

After aerating, scalping, and dethatching for overseeding, I did an application of 9-23-30 starter fert at a rate of 1 lb P/k and 1.25 lb K/k. That brings the total K for the year up over 4 lb/k, so hopefully we are at 150 ppm or higher on next spring's soil test.

Finally, I did a gypsum application to add 0.6 lb S/k to raise my sulfate levels a little bit since they are at threshold. Goal is to get sulfate up to about 10 ppm.

The lawn is doing extremely well recovering from the scalping so far. It will go crazy once I actually put down N since I have been holding back for germination and root development. If you have disease problems it seems like maintaining high P, K, and S levels without going crazy with N is a good strategy. Modern fertilizers tend to be very low in P and K, striving for "maintenance doses" only, so if you are short on available P and K it is difficult to fix those unless you can find potash and phosphorus specialty fertilizers.

I will do another pH test soon here to see if I need to add more lime before winter. I also have not addressed the micros yet, still trying to figure out the best way to do those in one shot.


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## Ridgerunner (May 16, 2017)

You're adding quite a bit of P and your P levels are already at the top of the sufficiency range. Keep an eye on those levels. No sense in creating excessive P induced issues. Otherwise: :thumbup:


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