Monday, February 10, 2014

Student Research: Pasture Intercropping System

Intercropping annual grains into perennial pasture

There are several reasons why two seemingly conflicting agricultural systems—annual grains and perennial pastures—might work well together.  The motives to explore this potential symbiosis relate to low input dairy production. Dairy farmers are faced with many challenges including the increasing price of grain. The purchase of organic feed grains represents a significant cost for organic dairy farmers in the Northeast and has led to increasing interest in on-farm production of grains. However, organic and low-input feed grain production often relies on intensive tillage for seed bed preparation and weed control, which can negatively impact soil quality. Intercropping annual feed grains with perennial pasture could reduce the need for intensive tillage, and may lessen the environmental impacts of dairy production and the need for purchased off-farm inputs.

Yet, despite the potential benefits of intercropping systems, little is known about the agronomic, environmental, and economic effects of intercropping annual feed grains into established pasture under organic and low-input management.

To evaluate these systems Jennifer Wilhelm and Rich Smith have established an annual grain rotation (corn in 2013) into alfalfa stands using a “gradient of tillage intensity.” Different tillage types fall on a spectrum of soil disturbance, from complete inversion of the soil (e.g. conventional tillage, or mold board plowing) to minimal soil disruption (e.g. strip tillage and no tillage). The traditional method of conventional tillage “resets” the entire soil and plant community, whereas strip tillage disturbs only the seeding row, leaving the inter-row plant community intact.

A Yeoman's Plow, one of several tillage methods used.
Different degrees of soil disturbance after the initial tillage is completed. 
Some tillage methods leave the alfalfa pasture intact more than others.

Of course there are always tradeoffs: We might expect intense tillage methods to favor corn growth, but also to disturb the pasture beyond recovery, creating greater space for weed community establishment. Low-intensity tillage may favor the pasture and reduce weed establishment, but the pasture plant community can compete with the corn for resources, reducing crop yield.

The results of the first year of this study will be available soon. This project is funded by a graduate student grant from the Northeast SARE Program.

After tilling, all plots were planted with grain corn....
...Jennifer in front of the corn later in the season.

1 comment:

  1. Want to do this very much would like to see results and equiptment used thanks josh email