In earlier pieces I have alluded to a soil problem in “Block A”, 5 acres of 15 year old lemon trees. These trees should be in the prime of their lives right now but this block has always struggled. In the past 2 years, nearly 160 (one fifth of the acreage) have crashed. Soil analysis has shown no pathogens. Our prime suspect is a clay pan which has developed only about a foot down. For the past two winters we have used covercrops to get more organic material into the soils. Barley and rye for biomass, crimson clover for nitrogen, and a blend of mustards for both their biomass and deep taproots.
The clover has been a disappointment. Hard to start, it has not shown signs of nitrogen fixing as we had hoped, and has been a minimal contributor to biomass, either above or below ground. On the otherhand, the mustard has performed quite well. Almost complete germination, resitant to brief heat, the blossoms helped support a humongous bee population while our trees were in bloom. Where there are bees, I expect there are other beneficial insects as well, so this should be helping with our integrated pest management efforts. Root penetration isn’t quite what we expected, but with water trapped in or above the clay, they haven’t needed to.
This coming month we will take our first stab at summer covercrops. We will alternate between rows with buckwheat, red cowpeas, and black-eyed peas. Since we have some crimson clover left over, we will also try a little as a warm season cover. Buckwheat is pretty much solely a biomass generator, but the others, being legumes, should give us some N. We may even harvest some of the black-eyed peas. Not sure if we can find a market for them though… This corner of rural/suburban Southern California isn’t a big soul-food kind of place. Anybody looking for some locally grown comfort food?
This summer cover program will go hand in hand with a high density replant of Meyer Lemons in the effected areas. The soils will further get a boost from tilling in the winter’s cover crop, a little organic sulfur, and a few shovels of our homebrew vermicompost for each tree. My philosophy is to “exercise” the soil, instead of “working” it.
Wish me luck!