Contact your local office of your state universities USDA Cooperative Extension Service about having that done and then dig in with these simple soil tests to see what you have. 1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top. 2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up. 3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart. 4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell. 5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

Generally, yes, Ca will knock K out of the exchange, but a lot depends on the amount of Ca and K. If there is a whole lot of Ca in relation to K, the amount of K becomes a bit moot even if it's high because Ca will generally out-compete for exchange sites. If there's just a similar amount or smaller amount of Ca than K then the K amount may remain rather stable in the soil or leech slower. Ca competes much better than K for exchange sites. Think of soil as being a piece of metal and Ca/K being magnets of different strengths...with Ca being a stronger magnet that can not only cling better to an exchange site, but push out K into the soil solution (and away from holding/exchange sites) easier for a site that K already holds. This makes K leechable while the Ca sticks around. Al > H > Ca > K > NO3 > Na...etc That said, we're talking about a MEGA TON (not very scientific, but whatever) of exchange sites in your soil...and just because something competes better doesn't mean it competes with 100% brute force. Even the weakest of competitors will still be found on exchange sites...it just may not be as much as more prominent competitors depending on the amount found in the soil. In the South-East soils are full of extremely strong Al, but Ca/K added to soil doesn't exactly wash out of the soil like it's nothing. As an aside...raising pH doesn't make the Al go away, it just makes it a form that's plant unavailable. The Al is still strongly in the soil and on exchange sites, but the way it's complexed in higher pH soils makes it a form of Al that plants won't uptake and therefore won't suffer from toxicity.

My $ .02. Depends on soil texture. Slow moving amendments like K, P, lime and OM are going to remain in and affect the top soil layer significantly for the first year after application. On finer soils (clays and even silty loams), this may be the top 1" or so, on coarser soils (sand and sandy loams) its going to be the top 2" or so. I discard this layer as I prefer to get a more accurate read of a deeper layer of my preferred root zone-either 1-4" on heavy soils or 2-4" on coarser or well floculated soils. On my son's heavy and my tight soil I sample from 1+ to 4". on a relative's sandy soil, I sample from 3" to 4". The important thing is to stay consistent from year to year when taking and submitting samples for testing. If you discard the top layer, then the affects of recent fertilization shouldn't be a problem. EDIT: I should add that if you are testing once a year, you should test a greater profile: 1 to 4" to help prevent over shooting your target.

Khalid: I responded to your excellent info. a while ago, but I didn't hit the submit button !! Corn cob is high in potassium, and the pore space it gives is excellent. Plus corn is much, much lower in salt than sulfate of potash at 43 salt-index, and muriate of potash (potassium chloride) at 112.6 salt-index. http://www.philstar.com/agriculture/2014/10/12/1379156/uplb-studies-viability-corn-cobs-alternative-fertilizer Corn cobs have potassium content averaging one percent, while the ash has a potassium content ranging from 21 to 33 percent. The study also aims to determine which among the different corn cob sizes (whole, chopped, finely ground, and ash) are most effective in releasing potassium to be used by the plants. It is found out that ash from corn cobs gave the best result in terms of growth and biomass production as it has higher concentrated amount of potassium. http://www.philstar.com/agriculture/2014/10/12/1379156/uplb-studies-viability-corn-cobs-alternative-fertilizer See below link on "acidic red clay" for the importance of "pore space" to provide oxygen for best root-growth. http://www4.ncsu.edu/~djgofort/Miscellaneous15.htm An ideal soil would contain 45% mineral, 5% organic matter and 50% pore space. The sandy soil down there won't hold nutrients. For proof you can look at the distribution of dairies. You will find none in the coastal plains. A 1000 pound milk producing animal can't get enough nutrients out of sandy soil to stay healthy. Texas has soil even worse. It can hold enough nutrients to raise cows but you would have a hard time plowing it. I have seen mud there build up in wheel wells to the point it would bust heavy duty military tires. I've seen good soil in Kentucky but parts of the state have creeks that always stay muddy. The clay soil is so fine it never drops out of solution. By the way, red clay is one of our better soils. When you have gray, brown, purple, white or yellow clay, the soil is worse but you deal with these soils the same way. Article was written by David Goforth Agriculture Extension agent North Carolina Cooperative Extension Cabarrus County Center. " http://www4.ncsu.edu/~djgofort/Miscellaneous15.htm