I do think it’s appropriate that we’ve finally gotten some rain on earth day. I took advantage of the weather to transplant the broccoli, cabbage and brussels sprouts. This kind of weather is perfect. I added a whole lot of dried blood (4lbs/100 square ft) and sunk the plants pretty deeply. I even put in some soaker hose because I’m afraid the dry weather will return.
The spinach and lettuce I planted almost a month ago now are looking pretty healthy and the peas I put in about two weeks ago are up and looking good.
I added a lot of dried blood because my soil test showed that my soil doesn’t have enough nitrogen. This is probably true, but nitrogen testing isn’t always perfect.
When I called one of our local garden supply stores to see if they had a large bag of dried blood, the gentleman told me it was “freakin’ expensive.” Tell me about it. I knew that I could buy a bag of standard fertilizer for a fraction of the cost. The blood is organic, true, but it’s hard to say whether I’m really improving long term soil fertility that way.
Thinking about long term fertility put me in mind of rock dust. Ever since I started gardening, I’ve been hearing opeople recommending the application of various types of pulverized stone and rock to the soil. These are mostly supposed to supply the trace elements that plants need. Elements like molybdenum, zinc, nickel, selenium, sodium and manganese.
In some quarters it is felt that these are depleted in the soil and that our plants will be healthier and their fruit more bountiful if the soil had more minerals in it. One of the biggest proponents of this view is a local organization called reminieralize the earth. They have a fine website full of really lovely pictures of enormous vegetables grown using rock dust.
The new Florence community garden spread 80,000 pounds of the stuff. A representative of Remineralize the Earth claimed that the dust “counters the effects of soil acidity, prevents erosion, increases the storage capacity of soil and has anti-fungal properties. It also repels insects, eliminating the need for pesticides.” Those are big claims. They’re also hugely appealing to someone who wants his plants to grow well so he can show them off on his silly blog.
The last thirteen years of my life have been squandered in laboratories studying plants. When I hear claims such as these, I want to seem some data. Anecdotal evidence is easy to come by; there are great pictures and lots of people tell you how they put some rock dust in the soil next to a plant and it got really big. I want a table that shows me dry weight and wet weight for both treatment and control. I want to see the block design that was implemented to minimize bias. Were the data statistically significant?
There is no doubt that putting rocks on your soil can change the mineral content. Rock phosphate and limestone clearly do the job. If I put a whole lot of rock salt on my soil, it’ll get salty. The question is whether pulverized granite or basalt will make a difference.
Now admittedly I only spent a few hours poking around Agricola, Google Scholar and a USDA site, but I couldn’t find anything with real data (you know, charts and numbers). I found some articles: http://infohouse.p2ric.org/ref/45/44601.pdf, http://ddr.nal.usda.gov/bitstream/10113/42473/1/IND44389025.pdf, and http://www.dolagi.se/documents/RockDustinAgriculture.pdf, but none of them gave good data. Well the one on composting did, but it found no signifcant difference. Of course, he only measured the temperature of the pile.
To my mind the minerals in rock dust would enter the soil very slowly and those in the soil now would leave the soil very slowly. I’m not sure that there really is a problem with micronutrients in most soils. There might be, but I don’t see the data.
I’m going into all this because I think it says more about who I’ve become in the last fifteen years. Before getting corrupted by academia and the scientific method, I’d try nearly anything in the garden that Rodale press or some sprightly young lady at the food coop recommended. I’ve tried a lot of things that “worked.” At least I grew good vegetables. Over the years I’ve settled on a system I kind of like, but it doesn’t always work.
Perhaps I need to try some and see if it helps. I’m just too lazy to come up with a randomized block design for the experiment in my garden.
