Garden on May 21, 2008
With all the new farm chores, I didn't have time to make a garden that year, so I decided to plant cover crops and see what happened. I planted Oil-seed radish on April 10th 2008 and roto-tilled it under when half was in flower on June 1st. Not surprisingly, it grew best where the low spots were in the original land - we had haphazardly leveled the topsoil and it was probably deepest there. The soil everywhere else was just too poor for them to grow.
June 7th I roto-tilled again, added the recommended amount of lime (I had taken a soil test by this point) and planted a pound of Cow Peas "Iron and Clay". The radish disappeared like magic in 7 days. Yankees would call Cow Peas beans - they are like little square brown black-eyed peas. I planted them in rows because weeding the hand sown radish had been a nightmare. A scuffle hoe made weeding the rows very easy, though making furrows with a board sowing a pound of cow peas by hand made me really want a seeder. Interestingly, the peas grew best where the radish did the worst. I'm guessing the radish released something that made it hard for the peas to grow. I used seeds from Johnny's seeds, but I ran out on the last couple of rows, so I substituted with some cow peas from a bucket at a local hardware store. They looked identical to Johnny's, but by August 23rd, when half the crop was starting to flower, the hardware store bucket peas were covered with aphids and wilting while Johnny's seeds were going strong. Any place I was able to top dress with any compost at all grew twice as well as any place the soil was unmodified.
On August 30th, I roto-tilled again and planted oats and clover with the help of my father-in-law. They grew very evenly and with essentially no weeds. The clover was slow to start and the oats died of the cold in January, but that was by design so they wouldn't hold me back in the spring. I also added an inch or so of compost and maybe 40 lbs/1000 sq. ft. of wood ash from the burn pile. The books recommended 25lbs, but it looked so insignificant. Mid February I took another soil test...
Malcolm surveying the oats on Dec 13, 2008
What coincided with my expectations:
Phosphorus raised 35% (from low to medium)
Potassium doubled (from medium to very high)
Calcium doubled (from low to medium)
Magnesium raised 35% (still medium)
Salts halved (still low)
The surprises:
Sulphur halved
Boron halved
Organic matter lowered 35%
pH went from 5.6 to 6.9
I don't know what happened to the boron and sulphur, but I have a pretty good guess about the organic matter. I thought I was building the levels of organic matter in the soil. But then I remembered that they tell you to be careful about how much you plow. Maybe they should say to be careful to plow when the soil is too warm in the South (plowing when the soil is too wet makes bricks - which is very bad). Remember how surprising it was that the radish disappeared in a single week? The beans did the same. I'm guessing a population explosion of microbes had a feeding frenzy to the point they actually left me with *less* organic matter instead of more. Doh!
Also, they mean it with no more than 25 lb/K sq ft of wood ashes. I would have been fine if I hadn't also added the recommended amount of lime. A pH of 6.9 isn't bad, but I definitely overshot the 6.5 mark.
Even so, the cover crops were a net plus. The soil texture is many times improved, especially if I dig deeply, the roots penetrated and did a lot of good there. Each crop was many times easier to grow than the previous. But I will be very wary about roto-tilling when the soil is warm, and apply the recommended amounts of ammendments in the future. I'll definitely look into cutting crops down with a hoe in the summer and letting them wilt on the surface instead of tilling them in.
