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

The Soil is Alive – Updates from University of Kentucky Integrated Plant and Soil Science

KCl Extractions Lab.png

The Soil Is Alive!

Did you know that a teaspoon of productive soil contains between 100 million and 1 billion bacteria? That adds up to equal the weight of two cows per acre! When you look down, you don’t see them, so they are easy to forget about. However, when you look down and see plants growing you have billions of microorganisms to thank! These microbes are vital in nutrient cycling and many other important processes taking place in the soil.

what's in a handful of soil

How Microbes Are Running My Master’s Degree

As I discussed in my earlier blog post, I am currently a graduate student at the University of Kentucky studying nutrient management in soil science. For my research I am conducting a laboratory incubation study comparing different types of poultry litter and the factors influencing the nutrient content of these manures. During my time at the University of Kentucky I took an in-depth soil microbiology class with a lab that opened my eyes to the importance of these organisms in agriculture. Soil microbiology is also a big part of my research.  I am in the middle of the first study and am currently processing samples as they finish incubating. The reason an incubation process is used is to facilitate microbial activity in the sample cups. These microbes are the ones doing the work to break down the poultry manure and transform the nitrogen into a usable form for plants to use. To create optimal conditions for microbial growth, the sample cups I prepare are kept at about 77°F and the soil is kept at about 50% of field capacity (that is a scientific term that pretty much means the soil is moist but will still crumble in your hand). This is important because it gives the microbes enough water but also allows for air to get to them. They are living organisms, so they need oxygen and water just like us. Over time I take out samples and analyze them for inorganic nitrogen content. I am specifically interested in ammonium (NH4+) and nitrate (NO3) in the soil that the microbes are releasing. This is done by extracting the nutrients from the soil with potassium chloride (KCl), filtering the samples, and then analyzing with flow injection analysis. Once two months of samples are collected, I will have a record of how much nitrogen was released and when it was released.

assembling sample cups with manure and soil            sample cups in the incubator

Goals of the First Study

This first study focuses on two main factors; the rate of manure (poultry, specifically broiler litter) applied and the method the manure is applied. Half of the cups received manure at a rate of 100 lbs of plant available nitrogen while the other half received 400 lbs of plant available nitrogen. This comparison will shed light on differences in the rate of nitrogen release as you increase the amount of manure applied. This study is also comparing a tilled and no-till manure application. For this comparison I mixed the manure into one cup and in an identical cup, I sprinkled the manure on top of the soil. This study is a chance for me to perfect my procedures and techniques before I begin the bigger study that will compare eight types of poultry litter from all around the country.

The end goal of my project is to collect data that will help crop producers improve their decision-making when considering using poultry manure. I am excited to see the results and will be sure to have an update post once I have the results of this first study!

If you want to learn more about the living soil and the microorganisms beneath your feet, check out these websites!

USDA NRCS Soil Health

USDA SARE The Living Soil

Lydia Fitzgerald: Student, writer, flower & vegetable farmer!

 

 

 

 

About Lydia

Lydia grew up on a farm in Nelson County, Va and helped raise wholesale pumpkins, apples, corn, and soybeans. She did work in food safety and certifications and started a retail sector with pumpkins, gourds, sunflowers, Indian corn, and sweet corn for a pick-your-own operation. Lydia has been involved in home vegetable gardening and loves to learn about different management and marketing strategies for small and large scale production systems. She is currently a student at Virginia Tech studying Crop and Soil Science planning to attend graduate school in the fall.

Sources:

https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053862

https://blog.rsb.org.uk/the-living-soil-tread-carefully/

Using Perennials

By Meylin Muniz

The Benefits of Perennials

Apples, pecans, asparagus, and blackberries- what do these delicious foods have in common? Depending on your climate zone, each of these can be planted once and with a little patience are the gifts that keep on giving (bonus: no seed-starting or tilling necessary!).

Perennials are Hardier and Require Less Care

As members of a more mature successionary stage, perennial crops are in it for the long haul. Their roots run deeper and thicker, allowing them to subsist with fewer water and fertilizer inputs. Annuals, on the other hand, demand more intensive inputs which are easily lost from their shallow and delicate root systems. This is where water pollution can become a common reality. The extensive roots of perennials also work to enrich the soil with organic matter and microbial life. The difference is so dramatic that conversion of land from perennial to annual agriculture has been shown to cut the soil organic carbon content in half over a 30-year period. Finally, the no-till-necessary perennial system reduces the erosion and soil disturbance weeds crave so much. Compare this with short-lived annuals which keep the land at the earliest stage of succession, making fast-growing annual weeds a persistent issue.

Why Are Perennials Less Prevalent?

Still, the elephant in the room remains- if perennials are so great, why are they so heavily outnumbered by annuals in food production? Over 90% of plants in nature’s reservoir are perennials, so the issue wouldn’t be a lack of options. Ironically, however, perennial crops- especially improved varieties- are difficult for farmers to come across. Up to now, scientists have worked almost exclusively on breeding and making specialized equipment for annual varieties.

Then there is the issue of wait time which doesn’t feel worthwhile for growers on rented land (slow and steady output is the perennial motto). A mix of annuals for immediate income and perennials for a value-added investment may be best. For some of the more quicker growing perennials, check out this page:

https://permaculturenews.org/2016/11/25/20-quick-producing-perennial-fruit-trees-vines-bushes-grasses/

Using Perennial Alternatives

Finally, not every annual has an identical perennial counterpart. Sure, fruits nuts, herbs, and flowers are easy enough additions. However, many perennial alternatives (particularly vegetables) are unfamiliar to consumers even if they are just as delicious! If you are still feeling adventurous after reading, feast your eyes on some of the perennial vegetables growing in your climate zone: https://bezmotika.com/applications/core/interface/file/attachment.php?id=1252

Or consider picking up a copy of Perennial Vegetables by Eric Toensmeier.

Integration of perennials may take the shape of agroforestry. Trees can be mixed with annuals, pasture, or both depending on the goals of the farmer. Typically, perennials are planted in fall to promote strong root growth through the winter, but this is only a general rule.

Use of Perennials is Expanding

Many institutions have taken notice of the benefits of perennial crop production such as increased landscape and financial resilience. For example, organizations like the Land Institute are working to “perennialize” existing annuals that make up the bulk of human nutrition like grains, legumes, and oilseed crops. Helping in this mission are scientists that look at the perennial food crops we do have in production. An interesting finding is that perennial crops have much fewer genetic bottlenecks than annuals despite being domesticated over thousands of years and showing differentiation from their wild counterparts. 

This suggests that trait selection doesn’t have to be at the cost of great losses in genetic diversity. With some of these exciting developments already in their final stages, we can expect to see foods like rice and wheat make their debut onto the perennial scene soon- part of a growing movement to give these tough plants a well-deserved chance in the field and on our plates.

Meylin Muniz

Meylin Muniz

I’m a Plant Science student at the University of Florida specializing in Sustainable Crop Production with a deep interest in closed-loop systems and regenerating soil fertility. If I’m not studying, I can also be found writing, running, and taking pictures of critters in the garden. During the summers, I spend time in Miami with family. I think food is a great way for people to connect; some of my favorites are mangoes, peanuts, and oats.