Soil tests for nitrogen are not always terribly accurate because the sample can loose nitrogen on the way to the lab.

If you are planning on using alfalfa on a regular basis, I would suggest putting some out in the fall, and incorporating the bulk prior to seeding in the spring. If you are a no-tiller be aware that it can get smelly if surface applied.

I apply at 10-20 pounds per 1,000 square feet, and have never smelled it. Your mileage may differ.

If you are gardening organically and they did not give you bacterial and fungal counts, then your soil test was likely one where they simply dissolve everything in hydrochloric acid and run it through a mass spectrometer. That test will give you a chemical analysis, but not a biological analysis. Soil microbes hold their nitrogen in molecular form as protein. If you just sniff for nitrogen, you won't find it. But if you weigh the little buggers, you'll get an assessment of how healthy your soil is and what the potential is for releasing nitrogen.

You can apply alfalfa any time, day or night, any day. If you apply it to frozen soil, it will lay intact until it gets moist, melts, and gets "eaten" by the soil microbes. That might not be until spring, but since you cannot know exactly what day the microbes will be ready to consume the alfalfa, you can put it down now and water it in. The only reason to water is to melt it so the birds don't carry it all away. Then as soon as the microbes are ready, they will have something to feed on.

Thank you both for your responses.

I don't know the exact soil testing method they used. I only know it is the free test that our local extension agency offers to county residents and farmers. They give a box to take about a cup's worth of soil.

dchall, your explanation of the microbes eating it when they are ready makes perfect sense. Thank you.

Take care,
Michelle

Nitrogen availability in soil is very dependant on the soils temperature, or as Dave alluded to biological activity. Most soil test labs have stopped testing for N for this reason. You can apply your meal anytime since any Nitrogen will be held firmly in that meal until the soil microbes start to function and covert that into a form the plants can use. The Nitrogen is not going anywhere, unless the wind carries the meal away, until then.

Last Spring I noticed my pepper and tomato plants growing very slowly, and they seemed somewhat weak. Since then, I realized I had laid down some wood shavings that hadn't quite composted. They were too close to the plants, drawing on the available nitrogen. I can't get alfalfa locally, but I did get soybean meal, which I applied liberally around those plants. I even took a dowel and punched some meal down towards the roots. In about 7-8 days, all those plants really perked up, and the whole season became a lot brighter! A lot of this microbiology is mysterious to me, but that was like my own little experiment which showed me some great results. Hope that helps a little.

"A lot of this microbiology is mysterious to me,..."

Unless you have a degree in it, it usually is. Check out the link for some info. Settle in, it's 50 pages or more.

Here is a link that might be useful: Soil Biology Primer

I would wait until planting time to put in alfalfa meal. The reason is say you plant zukini squash or tamatoe plants. I would work it in just the area you plant these large plants. If you plant beans then spread it over the soil and work it in before planting. By the time these plants are medium sized the alfalfa mean will be decomposed and feed the larger plant. Give small plants a dose of liquitd fish fertalizer now and then. By the way I buy rabbit pellets for my gardedn, roses and trees. It is cheeper that way and basically you get the same thing. The rabbit pellets do have a little salt in them and the alfalfa meal does too. Some things break down slowly and alfalfa will break down very fast, say in just a month or so, it will be already eaten by worms or the good bacteria will be working it in and the plants will benefit from it.
If put in the ground in Fall it might wash out if you get good amount of rain, plus it might be gone by the time you plant in spirng. Just my thoughts on how I would use it. BillC

If you have too little organic matter in your soil and you pile organic matter on top of your soil you may well see your plants suffer from a Nitrogen deficiency. But if you have sufficient levels of OM in your soil and an active Soil Food Web. The link below will get you to a paper on the the Soil Food Web.

Here is a link that might be useful: The Soil Food Web Primer