The soil in pastures is alive with various organisms, including the forage or crop growing on/in it. These complex living systems have biological processes very similar to human or animal bodies, right down to the preferred pH. I find it fascinating that as the soil becomes more mineralized the pH of the soil becomes more alkaline, just as it would in a healthy human body. The soil has circulation, nutrients, waste products, life cycles - all the functions of a body. All the components are interconnected, and there are synergistic (enhancing) and antagonistic (supressing) relationships between the components.
If you can view your land as a living organism, you can enhance health and increase production. Please, avoid the conventional N-P-K model. This approach to soils leads to nitrogen-addicted imbalanced soils and low-nutrient pastures.
There are many ways to make soil healthier. I have gathered up various tidbits and tips and links to give you some starting points for your research. I encourage you to muscle test or dowse your possible approaches to find what best suits your land.
If you are going to buy 2 books, add Weeds, Control Without Poisons by Charles Walters.
I also suggest learning all you can about the Albrecht Model of soil fertility. Here is a simple starting article. Albrecht's papers and talks are available on Amazon and from Acres USA.
I also encourage you to look into radionics and broadcast towers. I did a brief summary of both, with related links, here. The government cracked down on these a few years back, so information can be tricky to find.
Your first step, before applying any fertilizer, is to analyze your soil.
http://www.turfdiag.com/InterpretSoilTestReport.htm How To Interpret A Soil Test by Steve Frack. This is a fairly conventional discussion with good descriptions of the various components of a soil test
An excellent soil test service is Western Laboratories in Idaho. Contact me please for their phone number.
There are many foods for soils. In general, I believe fertilizers should be plant-based or contain chelated minerals for the best results. There are many many sources of healthy fertilizer.
Fertilizers can be made from sea vegetation. Wachters sells seaweed-based fertilizer that can also be used to bring up sodium and iodine levels in soils. You can do an internet search to find other sea vegetation fertilizers.
www.seaagri.com has some interesting information about seawater and sea salt fertilizer. There are lots of great links on this website, and information about how seawater works on soil. Keep in mind that seawater these days can be very polluted, so please muscle test or dowse any product you are considering.
[At Oak Hill, natural trace mineral salt applied at 2 pounds/acre tested well]
http://www.albionplantnutrition.com/ has a lot of information about chelated minerals. Albion and their founder, Ashmead, are the original chelate innovators, and a great place to learn the basics.
Composted manure is another fertilizer option. Generally, if you are applying composted manure, the best application time is early fall. You may want to consult The Old Farmer's Almanac for more precise spreading dates. Check your manure source. Manure from farms that use chemical wormers or herbicides may contaminate your soil.
Zeolite is a possible addition to a fertilizer program. It holds moisture and also traps toxins. Here are some zeolite resources:
If your soils test as acidic or low in calcium, you may be told to add lime. Before adding lime, consider your soil type. Calcium can be added as dolomitic lime (magnesium carbonate), calcium carbonate, or gypsum (calcium sulfate dihydrate). Choosing the wrong calcium can harden your soils or create a mineral imbalance. Gypsum raises calcium and sulfur levels without affecting pH. http://www.gypsoil.com/news-and-events/gypsum-and-lime
[Oak Hill does best with gypsum, as we have low calcium, high iron, high clay soil]
Now that you have a sense of direction for your soil-wellness research, go forth and learn! Your land will thank you.