You had a lively discussion last year, didn't you? I have a lower target for phorphorus than Morph had and I calculate that you're short on phosphate by about 1.25 lb/k. But instead of starter fertilizer, I suggest Milorganite. The main problem with alkaline soils is that phosphorus binds up quickly with calcium and is then not available to the plant. With Milorganite the phosphorus will be released gradually as organisms die. You will also get chelated iron. You're ok on potassium. So do your early fall fertilization with Milorganite. Use 20 lb/k to get 1 lb/k nitrogen and 0.8 lb.k phorphorus. I don't see what kind of grass you have (KBG, rye, fescue?), only that you're in the Midwest. How much nitrogen a year do you normally do? In general, when the soil is warm (and microbes are active), use an organic fertilizer that has some phosphorus (most do) and use synthetic when you're fertilizing when the soil is cold, like the late fall fertilization. I have not heard that cracked corn will lower pH. Sulfur is what lowers pH and it is not practical to try to lower pH over a yard with sulfur. You could use elemental sulfur to lower pH for a flower bed or planting hole. For times you use synthetic fertilizer, look for ammonium sulfate. It is the most acidifying fertilizer. Be sure to water it in. Don't worry too much about your pH. Grass will grow in alkaline soil.

Much better! Yes, you have a very sandy soil by the looks of it. With low OM which would help lift the ME a bit. Pour it on, but don't expect too much. Sandy soils allow in lots of oxygen, which decays the OM. Your pH doesn't disturb me, but with a sandy soil you're going to use a lot of resources very fast. This is another weird case where I want two sources--fast and slow release. Go purchase Encap or Mag-I-Cal limestone, a pure calcitic that's fine ground, in other words. Also get some dolomitic limestone, the cheap stuff with around 25% magnesium in it. In April, apply 2 pounds per thousand calcitic fine ground. Also apply about 7 pounds per thousand of the dolomitic (this one's not critical and if you accidentally apply more or less, it's fine--the stuff will take years to work). In October, repeat that. Try to adjust for April's error if you made one, but again, with the dolomitic that's not critical. I'm going to ignore your minor elements for right now. Increasing organic matter is going to change those...

I'm not a soil scientist like some of the people here, but I do read most of the tests as they come through. I have never seen anything like yours. You appear to have quarry quality limestone suitable for making cement. Be that as it may, I can help with the St Aug even with your soil. First, be sure you are deep watering on an infrequent basis. I'm in Bandera and have not YET watered my St Augustine this year. We have had almost no appreciable rain, but the dew and humidity have kept the grass dampish. Now that the grass is growing, I suspect it will tell me when to water with some wilting. A problem that many people have with St Aug is watering too frequently. Always mow at the mower's highest setting. There is never a reason to mow it any lower. You can fertilize now with any organic (grain type) fertilizer. Get that at a feed store. I like alfalfa pellets (rabbit chow) at 15 to 20 pounds per 1,000 square feet. If you like chemical fertilizers, wait until mid to late May to fertilize. The grass awakens with plenty of energy to make it until May. Any time now you can spray it for weeds with an herbicide with atrazine. Here is one such herbicide available at most places... Most of the atrazine herbicides have some purple packaging, but there are some purple packed herbicides that don't have atrazine, so read the labeling. Read the directions on this stuff several times. When I use it I walk backwards with the wind at my back. I try to do it on a calm day, but Bandera doesn't have many of those. And watch the overspray. This stuff takes a few weeks to kill everything, but all that will be left will be St Augustine. Use this stuff once now and try not to use it again this year. If you have to use it again, wait until September after the summer heat breaks. Since you are new to Austin, you should visit John Dromgoole's nursery. And looking back at your soil test, I think it's safe to say you can get some potassium sulfate (aka sulfate of potash) and start using that at at least the bag rate. The soil needs potassium, and the sulfate will get neutralized by the excessive calcium. It also needs magnesium, so there is a product called Sul-Po-Mag that has all the stuff you need.

"https://www.gardenmyths.com/bloom-booster-fertilizer-nonsense/" That is a completely reasonable and well substantiated premise! Unless previously heavily farmed, very few soils are deficient in P and rarely ever need supplementation. In some areas, phosphorus is a very heavy pollutant, especially when applied in its fertilizer form, and steps have been take to reduce its application. In fact, WA state has now prohibited including P in lawn fertilizer, perhaps the biggest contributor to P overuse and pollution. btw, plants bloom and fruit very productively without so-called "bloom booster" fertilizers. They are really unnecessary and more a marketing gimmick than a defined plant benefit. And just a FYI but very few land grant universities/extension services offer soil testing these days. Too expensive to staff and maintain the labs. UMass and TAMU are about the only two good ones left.