Friday, April 16, 2010

Examinations....


For years, Farmer Ricky has been seeing how no-till cardboard mulch-prepared beds can produce delicious vegetables without machinery and the kind of repetitive deep cultivation of the soil that can cause deterioration of the soil ecology. Earthworms are the key in his system - and there are lots of them, very soon after laying down the cardboard. One reason for applying for the SARE grant was to figure out what aspect of his method promotes this activity.

The 4 different beds described in the previous post are our attempt to pick this system apart a little. Here's the rationale:

Cardboard+Mulch Hay: These beds will have a layer of cardboard covered by 6" of mulch hay, Ricky's method of choice.

By covering the bed this way several things might be happening that attract the earthworms: conserving moisture, protection from predators (the robin's don't seem to want to pierce the cardboard!), temperature control, blocking sunlight, providing nutrients from breakdown.

To see which of these might be "the" factor, there are two other test conditions:

Newspaper + Mulch hay: By applying a layer of newsprint approximately as thick as the cardboard, and covering with the same amount of mulch hay, we will see if it is a property of the covering material itself (the glue effect?).

Mulch hay only: If we take away the first layer some of the shade, moisture and temperature properties will be different and we will see what effect this has. As mulch hay alone is a very common application to gardens - both permanent no-till raised beds and tilled furrow style plantings, we will have an analogy to more common practice.

"Undisturbed" beds: These will have no mulch, and will serve as the "control". They won't be totally undisturbed, though, because we have to treat them the same way as the other beds. For instance - when we applied the mulches it was a windy day, so we soaked the layers with water to keep them from blowing away - so we applied the same amount of water to the Undisturbed plots. That way, we are narrowing the search for effects to the mulch properties, not whether or not the bed got watered. Similarly, we compacted the mulch by lightly tamping it with the back of a landscape rake, so to have a "real" control on the undisturbed beds, we walked over them with the landscape rake too.

Over the course of the growing season we'll monitor the soil moisture, temperature, pH, organic matter content, presence of earthworms, and beneficial fungal colonization. We have three of each bed, so that measurements will be replicated for each condition, to provide some statistical data about how much variation there might be between beds within the larger plot.

Another exciting aspect of this research is monitoring the plants themselves for nutrient density (a term we'll look at in a future post)- we will monitor sap pH and the sugar and mineral content. Not to mention we'll monitor them for flavor!

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