My uncle and grandfather applied dry fertilizer to the stands of alfalfa/orchard grass every year and applied lime and fertilizer before discing the year that seed was drilled. A couple times we applied dry fert after 1st cutting just after chopping it. I'm not sure of quantities or how often lime was added. They always had a thick stand of hay. 

Get a real soil test from Kinsey Ag Services not a useless one like the county agent gives you.A good investment would be Kinsey's book Hands on Agronomy,get it from Acres USA

book store on line.

Sounds like you've got the pH about right so the plants can use whatever nutrients are available. Now you need to make sure the nutrients are there. You're going about it the right way: First step is always to get the pH right, then get your nutrients right. They say if a field needs both lime and fertilizer and you only have money for one, go with the lime. Breaking up the ground will probably show the biggest improvement. Subsoiling would be ideal on that hard pan, but even just conventional plowing will help tremendously. I suspect after 30 years there's not much of the original stand left, so you're liming/fertilizing volunteer growth. You can add oodles of fertilizer and lime, but you just don't have enough of a stand to be able to use it.

If breaking it up isn't in the near future, maybe try some frost seeding. Our land has very low pH levels and is so rocky that breaking anything up is a nightmare - every day spent plowing means a week of back-breaking stone picking. We're able to maintain our hay stands very well for up to 20 years without breaking it up by the right application of lime; fertilizer; and frost seeding clovers, timothy, trefoil, and orchard grass into it every spring. Some of the best results are obtained by mixing seed in with the lime, through if you're having it spread for you this isn't an option. Most of the time I do it by walking around the fields with a hand-crank satchel-type broadcast spreader that holds about 30 pounds of seed. Usually about 5-10 pounds an acre. Unfortunately the efficacy of frost seeding is very dependent on the spring weather. In a spring with lots of rain, the frost seeding can be almost as good as if it were drilled. In a dry spring, it's just a waste of seed. Alfalfa can be frost seeded quite well, but not into an existing alfalfa stand due to auto-toxicity issues. If you can get alfalfa established in that hard pan, the deep and thick tap roots will help break up that hard soil.

Each & every time a hay field has it's haying activities (cut/tethered/raked/baled) a major portion of crop (above the soil line) is removed by bales of hay. Maybe a reasonable guess of ONLY 5% of the crop total yield may be lost to haying processes; and hence, stays in hay field to decay, feed earthworms, & re-fertilizer hay crop for future crop yields? If so, how many tons of the 95% hay crop get removed each baling event ~ total tons removed annually (baled 3-4 times per year)?

How do acres of a forest / timber of Oak / Walnut / Sequoia trees survive decades or even centuries without lime, fertilizers?  Answer; Those tree's own decaying leafs, their decaying dead tree limbs, dead trunks, dead roots, etc. Soil microbes/fungi/earthworms etc convert decaying plant material back into soil nutrients. Everything stays. In 5+ years, soil life stabilizes & becomes very efficient converting decaying plant tissues back into more readily available soil nutrients.

Modern day farming can be brutal on crop field soil sustainability. If Livestock is still existent, then it's manure spread back onto crop field helps replenishes some soil nutrients?

Before modern day fertilizers, farms had their own fertility rotations(3-7 crops?)

Crop 1: (Cereal grains) wheat which usually had a plow-down legume frost seeded into them during winter months. After cereal grains were harvested, it's stems/leaves/roots decayed & re-feed soils. The legume continued to grow and could be briefly pastured or hayed and then before next year's corn crop, legume's stems/leaves/roots were plowed under to terminate legume & slowly decay to re-feed soil for next crop.

Crop 2: Legume green manure was useful to fertilize crop 2 (corn ear corn) which is a heavy nitrogen feeder. Ear corn is harvested but remainder of corn plant's stalk/leaves/roots stay in field to decay & re-feed soil. Ear corn cobs eventually come back to field via livestock manure.

Crop 3: (soybeans) which fix nitrogen nodules into it's roots. Soybean seed is harvested/removed but rest of plant's stems/branches/leaves/roots are left to decay & re-feed soil.

Crop 4: (Cereal grain) oats used to feed draft horses? Could be frost seeded to legume ~ figure same as Crop 1's soil nutrients re-feed by decaying plant tissues.

Crop 5 (Alfalfa or Clover/timothy hay) crop is grown for livestock / draft horse food. Livestock manure is spread back onto hay crop helps. But if like most farms, a well established hay crop continues for years (3-5?). In that case, hay roots stay living & don't decay. WHAT ~ OH SNAP! Yeah hay crop's roots don't offer any decay food. So every year a hay crop continues, a supplemental food needs to be added to that field.

So,,, If your farm has grown a 30 year hay crop, how much soil nutrient has been depleted by tons of above soil plant tissues removed & no decaying roots in soil??????

Maybe rethink adding necessary crop rotations to supplement your farm's hay crop or can continue to purchase fertilizers/lime/ etc...??

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Search for YouTube videos of Dr Christine Jones. Sort by most recent, look for her new Zeeland project.

There's a lot of conventional advice in this thread, that will give you conventional results and conventional problems to deal with.

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Growmark can come out and spray for you. $18 per acre for their operator and sprayer. Chemical cost is dependent on what you are looking to do. If you are shooting for an all grass hay crop, then there are plenty of low cost options. 

Planting new hayfields is easy. I’m sure you already have the equipment, a good grain drill with grass boxes. I suggest either oats or wheat as a nurse crop, about a bushel and a half to the acre. Best to have a good chemical program. 

If you plan to do some no till, but you worry about compaction, then you can plant tillage radishes in august, or now, with a no till drill, and then plant the hay crop in the spring. They should penetrate down to the 8-10” depth you would get from tillage. Not to mention they taste great.