Spring Growth

Spring Growth

Monday, July 9, 2012

Dust Mulch

Helloooo out there!

Well! We certainly were happy for a bit of rain. We got a solid 3 tenths of an inch. Not completely fabulous, but nothing to sneeze at, either. Paul spent the entire day yesterday "dust mulching". Dust mulching is an old dry farming technique used to conserve soil moisture gained from the rain. "Dry farming" refers to farms that do not use irrigation. We do irrigate (a lot this year!), but the practice of dust mulching is still very beneficial to the farm, especially in a dry year. 

How do you dust mulch? After it rains we wait until the moment that the soil is just dry enough to bring one of the cultivation tractors through, and then we basically go through the whole farm and cultivate (that means use a tractor to weed by stirring up the soil in some way) everything that we can. So, basically we tractor- weed the whole farm as quickly as we can. What does this do for conserving soil moisture? When the tractor goes through the top 2 inches or so of soil and stirs it up, that top layer of soil dries out very quickly. Once it is dry, the moisture in the soil below it can no longer wick up and evaporate away. The soil moisture gets trapped under that 2 inch layer of dry soil. It really is amazing how well lit works. The moist soil below is protected by a dust mulch. 

After we go through and dust mulch the farm it looks kind of depressingly dry. But, it is an illusion - down under that dry soil is a bunch of lovely moisture. Of course the exact amount of moisture under there is determined by how much it rained in the first place. In our case, not too much. But, by spending the day dust mulching (and getting a bit of weeding done as a side benny), we made sure that we preserved the rain that we were lucky enough to get. So, I could go on and on (really), but I will stop for the time being because there is a whole field of fall and winter kale to transplant today.

head lettuce - Frankenstein
salad mix
baby beets and beet greens - eat the whole thing!
green onions - ditto
zucchini plus a little patty pan and crook neck squash
European cukes - the cucumber beetles got to these this year - so the skins are scarred, but the insides are absolutely delicious

The chard and kale are on the One Bag Side again this week. We have been irrigating them weekly, but irrigation is just not the same as rain. I'm sure they will return to the free choice side at some point soonish. 

raspberries - 2 quart season limit
all flowers - unlimited!
basil - unlimited!!! As far as the plants go, THIS is the time to make and freeze pesto , not in the fall.

See you at the farm,


wildmom said...

Dust Mulch is the direct cause of the Dust Bowl in the 1930s. It is an illusion that it protects from loss of soil moisture; it is a reality that it makes top soil loss more likely. Bare soil cannot keep moisture from evaporating during a sunny day. The best you can say for cultivating after a rain is that you're doing some weeding.

Michael Rienstra said...

A neat article on dust mulching by Linda Chalker-Scott: http://puyallup.wsu.edu/~linda%20chalker-scott/Horticultural%20Myths_files/Myths/magazine%20pdfs/Dust%20mulches.pdf