Cover Cropping – Techniques for Creating Productive Soil

Cover Crop

Part 1: Should You Cover Crop? 

Yes! But only if you are willing to put in the time, money, and effort that having a successful cover crop requires. Most farmers are dubious about starting the journey because of the many associated costs and risks, and this is fair. However, when implemented with care, cover crops can make your crop and soil highly successful and productive. This article will illustrate some of the many benefits by talking to you about the story of walnut farmer Russ Lester. Later, once you’re convinced this is the way to go, I’ll give you the basics on getting started. 

What are the Benefits?

To start off, the benefits of cover cropping are a reduction of soil erosion and enhanced nutrient cycling which contributes positively to soil physical, biological and chemical properties. However, the success of the cover crop depends on the type of cover crop, timing and management as well as the crop that you are growing alongside or after it. 

Success with Cover Crops at Dixon Ridge Farms:

Russ Lester, co-owner of Dixon Ridge Farms, has been very successful at implementing a cover crop system on the walnut farm. Lester says, “We don’t just look at how cover crops can supply fertility; we look at how they can suppress weeds, conserve soil moisture, attract and keep beneficial insects, cool the orchard, and supply cover crop seed for next year.” He does this by using a “Rich Mix,” made up of Lana (wooly pod) vetch, purple vetch, common vetch, crimson clover, sub-clover, burr medic, oats, cereal rye, and barley, to maximize his cover crop benefits.This mix provides the low carbon to nitrogen ratio, meaning that C and N are cycled back into the soil, leguminous crops like clover and vetch fix nitrogen directly making them available for plants and uses water efficiently from the soil surface via irrigation. Evaporative losses are minimized because of the high soil organic matter from previous cover crops, which hold more water in the soil. In addition to this, the quick growth of the cover crops protects the water from evaporative losses. Weeds are also not a concern because they are quickly smothered by the planting and their growth is suppressed. 

Timing is Everything 

The process should also be timed to maximize benefits. A trade-off for cover crops is that it utilizes the water for the main crop, which is an issue in drought-prone environments like California. This is counteracted by growing the crop during the walnut tree dormancy, where the water use of the walnut tree is very low.  Cover cropping has a cost – seed and soil preparations and labor requirements factor into implementing the system. Although there is no direct profit associated with the process, it does increases water holding capacity, soil infiltration and soil biodiversity. It increases nutrient availability and nutrient content, soil stability and also suppresses weeds. This also means that the soil is able to absorb water from irrigation, rain and runoff from neighboring land, contributing to groundwater recharge which is especially important in California’s climate. Because of these reasons, at Dixon Ridge Farms, where the cover seed mix is produced in-house, the benefits are worth the expense. 

Cover cropping practices, if implemented well, can ultimately reduce costs for farmers by saving on irrigation and fertilizer, contributing to soil health, assisting in nutrient uptake (potentially contributing to greater yields); while at the same time decreasing demand for mining of minerals and contributing to groundwater recharge, adding to overall sustainability!

Taking the Plunge

So you’ve decided to take the plunge and start cover cropping. That’s great! There are a few key factors that you will have to work within and this entry is going to break them down for you. Cover crops are for the soil instead of for direct consumption, but they need to work within the framework of your typical growing practices. A successful cover process is a balancing act between the needs of the soil, and what you are willing and able to give. It may seem daunting to throw in an added element into the mix, but with some planning, time, and practice, the payoff is worth it.

What is your Cover Crop? 

Depending on the amount of time your fields are left fallow, and the nature of your crops, decide what kind of cover crops are even available to you. When growing a cover crop, it must suit your needs. If your crop has a long growing season, and your fields are fallow for a short time, you may consider Triticale. Triticale is an easy and quickly-established cover crop that adds increases soil organic matter. It doubles as a weed suppressant and grazing grass for livestock. On the other hand, On the other hand, if you are growing corn, for example, you may choose to cover with a mix that is predominantly leguminous. By growing legumes like hairy vetch and crimson clover, you add to the soil nitrogen stock by introducing desirable nitrogen fixing bacteria. The type of mix used can be manipulated to best suit your needs and give you the most bang for your buck. 

What do you have now? Time:

First, how much time do you have? You can do cover cropping for long or short periods of time, depending on the season, the dormancy of your crop/orchard, they type of mix you are using

  • Mix/following crop/soil needs 
  • Kill type/time
  • Season

Key questions are what do you want out of the cover crop, where are your problem places and in what time frame are you looking to see a return on your investment? All these answers play a role in deciding what type of mix, when it’s sown, how long is grown and how it is maintained and integrated with the overall agricultural practice of your farm. 

Shailaja Chadha

About Shailaja Chadha

I am a fourth-year student at the University of California, Davis studying Sustainable Agriculture and Food Systems. I chose this major because I wanted to study how people are connected to the ecosystem through food and the implications of our current food system. I am very interested in soil health and sustainability and am looking to pursue higher education in soil science and nutrient cycling. I joined ADAK Software as a blogger because I wanted to be able to share the things I learn in the classroom and on the field with everyone who is interested, in words that anyone can understand. I hope to eventually return to my home country, India, and develop agriculture and sustainability there to create a more equitable social, environmental, and economic system.

Sources

Agriculture Sustainability Institute  — UC SAREP. Retrieved from http://asi.ucdavis.edu/programs/sarep/about/copy_of_what-is-sustainable-agriculture/practices/cover-crops

California Agriculture http://calag.ucanr.edu/Archive/?article=ca.v048n05p43  

Dixon Ridge Farms.Retrieved from http://www.dixonridgefarms.com/farmingandprocessing/sustainability.html

Russ Lester — ASI.Retrieved from http://asi.ucdavis.edu/about/external-advisory-board-1/russ-lester