Dispatches from Chile: The Mystery of Walnut Sector 2

Chilefarms
Friday, January 27, 2017

Three sectors of walnut trees were planted on Chilefarms last August. Ricardo has asked Rodrigo, an agronomist, to inspect the sectors. Rodrigo says that the trees in sector one and three are doing just fine. Some of the trees in sector 2, not so good. A few appear to be dying and some are growing more slowly than the others.

What’s up?

Rodrigo decides to do some random checking. He suspects some trees may be receiving too much water from the irrigation tubes that run alongside each tree.

As he watches, Juan Vila digs up soil at the base of several trees. At one tree, Rodrigo hands me a handful of soil. He speaks enough English so I can get the drift of what he’s doing. He wants me to crumble a handful of soil that’s been dug up. It is moist but crumbles easily. “Good,” he says. Juan Vila replaces the soil and both of them replace the poles that help the tree maintain its shape.

Next Juan Vila digs up soil under a tree that is clearly dying.

“Try to crumble this,” Rodrigo says. It is a heavy chunk of clay soil so thick that I cannot make it crumble. It feels like the clay I used to play with when I was a kid. The solid clay is so thick and heavy that roots cannot penetrate it and the tree is dying.

Ricardo arrives.  A pow-wow ensues. The trees in this sector that are doing poorly are all next to the alfalfa field. And the affected trees are all next to a low point in the footpath between the fields.

Eureka.

During the weekly irrigation of the alfalfa field, water from the irrigation ditch a few feet away is cresting the ditch and migrating into walnut sector 2. Ricardo will have the ditch deepened. Water meant to irrigate the alfalfa field will stay in the alfalfa field.
Water will no longer migrate toward the adjacent walnut trees and load the clay soil with so much water that the roots cannot grow properly.

Not all problems on the farm are solved so quickly. This is a good day.

The story in photos.

While Luis applies herbicide to control the voracious 'malessa' (weeds), an agronomist inspects the tree roots. The soil under this tree is not compacted with too much water. He points out that tiny roots are growing through the soil, a sign of good health.

Juan Vila replaces the soil; they replace a 3 meter pole of bamboo and a sturdy shorter pole that supports the tree as it grows to maturity.

Next, they inspect a tree that is clearly dying. The clay soil is soaked, so heavily compact that root structure cannot penetrate it, depriving the tree of nutrients. If I were to leave a chunk of it in the sun, it would be hard as a rock in one day.

Ricardo arrives; the problem of over-watering is discovered. Water meant to irrigate the adjacent alfalfa field has migrated into sector 2 of walnut trees.

Next on the to-do list - dig a deep enough irrigation ditch so water will not crest it and flow into the walnut tree sector.

A view of the alfalfa field and walnut sector 2 next to it.

Photos by Paul A. Tamburello, Jr.

 

Comments

[Susan Sullivan]

Interesting Paul. We live in a very heavy clay area. North Cambridge and W. Somerville. The water table is high because the moisture does not penetrate and go down, hence damp basements. Trees, vegetation does well but flooding can occur. Phil is constantly trying to combat it. Enjoy your summer retreat.

[Jeffrey P Piccoli]

So the take away from this tale is walnut trees on Oliver St?

[Paul A. Tamburello, Jr. aka pt at large]

i wish. The only walnuts that show up on Oliver Street will be from Star Market!