Monday, December 12, 2016

Weighing the Benefits of Cover Crops in Almond Orchards

Drive around the farmscape around Madera or Mendota and you’ll likely find green ground cover growing between the rows of almond trees.

Cover crops -- not weeds -- are growing in almond orchards.
Are they weeds? Probably not.

It’s a good chance the vegetation is a cover crop growing on the orchard floor, which is an important sustainable farming practice aimed at improving nut production.

“Growers see quite a few benefits in it,” says almond field scout Jenna Mayfield.

A cover crop can be good for hone bees. (UC IPM photo)
Cover crops have been around for centuries as a way to rejuvenate the soil by adding organic matter and nutrients from legumes or broad leaf plants. They also control soil erosion.  But the emergence of inexpensive commercial fertilizers and herbicides prompted growers to drop the practice in the 20th century.
Today, cover crops are regaining popularity because of growing concerns about the environment. They also are good for the honey bee population.
Here are some of the benefits:

  •      Allows water to soak into the ground and keeps the soil from washing away. Producing less run-off improves water quality downstream.
  •    Controls weeds and keeps the soil from drying out. This creates firmer ground for better access to the orchard in the fall and winter.
Clovers are among the popular selection for cover crops.

Of course, there are challenges for some Valley growers.

Like any plant, cover crops need water to flourish. That can mean a higher water demand for the orchard. It also can reduce soil moisture stored from the winter rains – water that would normally be available for the trees.

Also, a winter cover crop reduces the amount of heat absorbed by the orchard floor, which can increase the risk of frost damage after leaf out in the spring.

The cost to plant a cover crop ranges from$15 to $50 an acre for seeds with the average running around $35 per acre. Soil preparation and planting usually adds another $45 to $65 per acre. Jenna says more education and outreach is needed for growers that are on the fence about the value of cover crops – especially those with orchards in the Valley’s west side, which is drier, windier and more water-challenged than other areas of the region.

“There are a lot of factors they need to consider,” Jenna says.

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