First of all, I’ll get my confession off my chest. A savvy reader spotted an error in my book Sustainable Market Farming: Take a red pen and correct your copy!
In Chapter 20, Sustainable Disease Management, on page 135 I said “Pathogens can infect the seed via several routes . . . Insects that feed on the plant can transfer the disease (striped cucumber beetles vector bacterial wilt, which is caused by Erwinia tracheiphila)”
It is true that striped cucumber beetles vector bacterial wilt, which is caused by Erwinia tracheiphila. It isn’t true that this disease is seed-borne. I don’t know where I got the wrong information from. I don’t yet know of an example of a disease spread by insects that can become seed-borne (that I feel confident about!).
I’ve asked my publishers, New Society, to correct that mistake next time they reprint. I wrote to the attentive reader, thanked her, and asked her for leads on where to find information about seed-borne diseases brought in initially by insects.
Meanwhile, I can recommend two books on seed growing (that weren’t out when I wrote my book), that contain good information about which diseases are seed-borne. I reviewed the impressive The Organic Seed Grower by John Navazio a while back..
Newer is The Seed Garden: The Art and Practice of Seed Savingfrom Seed Savers Exchange and the Organic Seed Alliance. Including “advice for the home gardener and the more seasoned horticulturist alike”, this is also a book from people who work growing seeds, and know their stuff. I plan to review it one week soon (when the work pace slows a little!)
If you’re a seed grower, you might want to add one of these to your wish list. Both are beautiful books, as well as clearly written ones.
This year I am not doing quite as much seed growing as some years. For sale, we are growing Carolina Crowder cowpeasin our hoophouse. Click the link to see photos.
For ourselves, we are selecting and saving seed from our Roma tomatoes and Crimson Sweet watermelon, as well as West Indian Gherkins. We are also saving garlic and shallots for replanting.
It’s that time of year when I line up events I’ll be speaking at in the fall and winter (and to some extent, into spring). Here’s my plan so far:
Then I will be doing book signing at the tent called The Shop at Monticello (at the Visitor Center), 2.45-3.13pm.
On Saturday I will be offering another premium workshop, Producing Asian Greens. This one is at the Vegetable Garden Tent at the Mountaintop (where most of the Saturday events are). It’s immediately followed by another book-signing, 5.30-6.0pm. The Festival ends at 6pm. All day Saturday is packed with events, and a General Admission ticket will be all you need apart from tickets for premium Workshops.
The following weekend, September 18-20, I will be at the Mother Earth News Fair, Seven Springs, Pennsylvania. The schedule is not yet firm, but I will be presenting The Hoophouse in Fall and Winter probably on Friday September 18 4-5pm at the Mother Earth News Stage, and The Hoophouse in Spring and Summer on Saturday September 19 10-11am at the GRIT stage.
I will also be signing books at the Mother Earth News Bookstore at some point and doing some scale demonstrations of string-weaving for tomatoes at the New Society Publishers booth.
Here we have a second day of cold grey drizzle. The day length is as short as it gets. I have little enthusiasm for working outdoors. But this is a good time of year to remind myself why I value growing good food in a sustainable way. I want people to live healthy happy lives, and I want us to leave a planet worth inheriting.
I’ve just been reading Can organic crops compete with industrial agriculture? by Sarah Yang from Media Relations at UC Berkeley. There is a common belief that while organic farming is better in terms of doing less damage to the environment than chemical agriculture, it cannot ever feed the world. Sarah Yang says “A systematic overview of more than 100 studies comparing organic and conventional farming finds that the crop yields of organic agriculture are higher than previously thought.” And the productivity gap could be shrunk from 19.2% to an 8-9% difference in direct yield by sustainable organic farmers adopting or improving on certain practices.
The full study, entitled Diversification practices reduce organic to conventional yield gap, by Lauren C.Ponisio, Claire Kremen and others from UC Berkeley,was published on 12/10/14 in the Proceedings of the Royal Society. Global food needs will likely increase enormously in the next 50 years, and even if we were prepared to accept hugely increased environmental degradation from chemical farming, the fact remains that chemical fertilizers cannot increase yields by much above current levels.
The researchers did a meta-analysis of 115 studies (three times more than any previously published study) comparing organic and currently-conventional agriculture in 38 countries and 52 crops over a period of 35 years. Yields from organic farms are on average 19.2% lower, although this may be an over-estimate. The various studies incorporated here show a very wide range. In some developing countries with few resources, adopting good sustainability practices increased yields 180% over the previous systems in place.
I doubt the recorded yields take into account the land lost by erosion, or that used for mining minerals for fertilizers or growing corn for bio-diesel for the extensive farm machinery used in currently-conventional farming.
Shifting away from environmentally damaging agriculture would be a good step. Increasing the land farmed organically from the current 0.9% and “Broad adoption of sustainable agricultural methods is unlikely, however, unless such methods are similarly productive and/or cost-effective, such that they improve livelihoods.”
How can organic farmers increase yields? The report suggests big yield improvements can come from giving more attention to crop rotations and multi-cropping (growing several crops together on the same field), two basic tenets of organic farming. (We can always aim to do these things better!) Other suggestions include increasing ecological diversity and harnessing ecological interactions by intercropping or cover-cropping with legumes to gain their nitrogen-fixing benefits.
More investment in research into organic management systems and breeding varieties (especially of cereals) suited to organic growing could (can!) reduce or in some cases eliminate the gap. Organic farming has been historically underfunded compared to agriculture which uses lots of products from Agribusiness, and crop varieties designed to work well with those synthetic inputs.
The senior author of the study, Claire Kremen, makes these important points: “It’s important to remember that our current agricultural system produces far more food than is needed to provide for everyone on the planet. Eradicating world hunger requires increasing the access to food, not simply the production. Also, increasing the proportion of agriculture that uses sustainable, organic methods of farming is not a choice, it’s a necessity. We simply can’t continue to produce food far into the future without taking care of our soils, water and biodiversity.”
Another interesting piece of recent farming news is the 12/2/14 report by Ken Olson from ACES Cover crops can sequester soil organic carbon. This 12 year study at the University of Illinois showed that cover crops do not increase crop yields, but do increase the amount of sequestered carbon in the soil. This benefit accrues in no-till, chisel-plowed and moldboard plow methods. the no-till system including cover crops, sequestered the most carbon. Ken Olson said that soil organic carbon losses caused by tillage, water erosion, soil disturbance, aeration, nitrogen injection and mineralization were less than soil organic carbon gained from cover-crops.
The complete study Long-Term Effects of Cover Crops on Crop Yields, Soil Organic Carbon Stocks and Sequestration can be read here.