Thanks FWJ.
Barry: I'm in central Massachusetts. Currently, the fields are a mix of orchard grass, timothy and clover. Alfalfa, I'm told, is too hard to grow in this climate/area. Don't know how true this is but that's the decision made by my neighbor, who, more or less, currently maintains the fields.
Your weed notation has me thinking, and no, my wife would not be pleased (I would be thrilled, either). As I want to go purely organic, what are my options? Killing the field for a season and starting from scratch?
The 50 gallon figure comes from the type of liquid fert. I've been considering, the AGgrand stuff based on emulsified fish parts and potentially, liquid lime (pending results of a soil test). Recommendations of this fert. is 1-2 gallons of fert. per 25-50 gallons of water. In washed out fields, such as mine, that have gone unfertilized for a decade, they suggest a higher concentration until the soil gets up to snuff... from 1 to 3 years. This make sense? If you've heard of the AGgrand stuff, what's your opinion of it?
Sorry so long getting back, but I was finishing first cutting finally.
The problem you will run into with alfalfa is getting it to dry, you may not get it dry period. Clover is even harder to dry than alfalfa. Clover usually takes a good day longer than alfalfa, and that is in 90 degree weather. Clover is also covered in very fine hairs that when dry turn to dust. Clover is usually black by the time you get it dry enough to bale. Orchard and timothy should do fine up there. I would likely lean toward the timothy as you have hard enough winters to take care of the cereal rust mists that destroy timothy further south. Orchard will get ready early, timothy is 4-8weeks behind orchard. You can play with orchard some by mowing it several times in the early spring to it does not grow to hay before you have the weather to make it. ALWAYS!!! cut orchard and timothy with cutter bar at 4 inches. These grasses store their regrowth energy above the soil. Fescues store this regrowth under the soil so they can be cut really close.
As to weeds and options, there is no weed control that I am aware of that is organic. Killing off a field and restarting does not get rid of weeds as there are decades worth of seeds in the soil just waiting to sprout. Weeds are mother natures way of starting to rejuvenate the soil, and add organic mater to the soil (the roots of the weeds). Weeds are also a sign of unhealthy soil. You cannot "restore" your soil to health in only a year or two, it takes many years. Judicious use of herbicides is not a sin. There are several broad leaf herbicides that have no grazing restriction for horses, that is how safe they are. (Cimmaron plus, Forefront, or Milestone come to mind,and all are very effective)
One of the biggest problems with soil on the east coast is that it is low on calcium. pH is not a reliable indicator as to available calcium in your soil. You will need to look at the base saturation or the CEC (cation exchange rate) Soil, depending on what you have, will need 3500 pounds or more available CA. Short of this and your soil does not stand a chance of functioning properly. I have extremely productive fields that have pH close to 8, and calcium in excess of 5000 pounds per acre. These fields grow some of the finest horse hays you ever wanted to see. You can base a resonable fertility program on lime, manure, and some N for the grass. Personally I wanted to do organic when we started this farm and hay operation, but I found out how impractical and virtually impossible it is to achieve clean hay on any kind of scale. What I personally do is what can be termed biological farming. There is judicious use of herbicides and insecticides while my soil is rebuilding. I want to send you to a website to explore and see what you think. It is the site for Growers Mineral Solution. This operation is based on the research that Dr Tedjens did in the 20's and 30's. You will find it facinating. Personally I have alfalfa fields that have not seen pot ash for years, and with the lime and growers I can show you soil test that confirm that I have more K available now than I did before I started using growers.
Growers Mineral Solutions- liquid nutritional plant food and livestock mineral supplement, non toxic plant food
Soild does not "wear out" Nature is very intricate, and can give it's plants everything they need. BUT if we can get the soil healthy, nature can work the way it has since the beginning. One of the responses early suggested using commercial P and K. Where does the K come from? That would be potash. What is potash- potasiumchloride. What is used to sterilize municipal water systems? Yes, chlorine. Alfalfa, the "common" knowledge is that it is a K pig. NOT TRUE, it is a calcium pig is the calcium is there. Put KCl on your field and where does the chlorine go???? That would be into killing the bacteria in your soil, but I digress on my soap box.
As to the AGgrand Stuff. What I have seen of the fish emulsion stuff is that they do not work. Get your soil healthy with high calcium lime, NO HIGH MAG LIME, some urea or amoniumsulfate for your N, and growers along with what ever manure you have, and you will grow a nutritious low potasium hay that is good for your wife's horses. Remember when moma is happy, every one else stands a chance.