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Archive | Soils

Cover Crops on the Farm

Cover crops are increasingly being used by farmers across the country to suppress weeds, conserve soil, protect water quality and control pests and diseases.

A mix of rye, clover and vetch.

The fourth annual SARE/CTIC Cover Crop Survey, collected data from more than 2,000 growers from 48 states and the District of Columbia and provides insight into cover crop usage and benefits as well as farmer motivation for including cover crops as components in their farm management and soil health plans.

Responders reported a steady increase in the number of acres they have planted to cover crops over the past five years. They said the most important benefits of cover crops include: improved soil health, reduced erosion and compaction and increased soil organic matter. Other key benefits of using cover crops include: weed and insect control, provides a nitrogen source, attracts pollinators and provides deep taproots.

In the 2015-2016 survey, SARE and CTIC sought data on how farmers manage their fertilizer inputs as a result of their cover crop practices. Cover crop users were asked to indicate their level of agreement with a series of fertilizer-related statements, using a scale ranging from 1 (strongly agree) to 5 (strongly disagree). The statement that got the highest level of agreement was, “Using cover crops has enabled me to reduce application of nitrogen on my cash crop,” with 134 of 1,012 respondents strongly agreeing and 244 checking “agree.” The statement that had the highest level of disagreement was “Using cover crops has required me to use additional crop fertility inputs over time to meet the needs of my cash crop.”

Cover Crops & Yields

For the fourth year in a row, the survey found yield increases in both corn and soybeans after cover crops (1.9 percent in corn and 2.8 percent in soybeans). According to the survey analysts, “Those are modest bumps, but they are statistically significant. A new angle of exploration — on the effects of a cereal rye cover on a subsequent crop of soybeans — revealed that a majority (52 percent) responded that their soybeans often or always rise after a cover crop of cereal rye. Notably, 82 percent said cereal rye cover crops helped with weed control. In all, the popular practice of planting cereal rye cover crops before soybeans was validated in this year’s survey.”

While a majority of those surveyed saw no loss in profit or lacked the data to tell, about one-third found a profit increase from cover crops, and two-thirds of the respondents said cover crops helped yields remain steady during extreme weather events.

Cover Crop Mixes & Timing

Cereal rye was the most popular cover crop species in the survey overall, followed by radish. However, cover crop mixes were planted on nearly as many acres as cereal rye. More than half of participants in the survey reported that they started with single species of cover crops and “graduated” to mixes, while another 17 percent started with mixes and increased their use of blends (61 percent of the respondents said they designed their own blends and 22 percent relied on their crop consultant or cover crop seed dealer to work with them on developing a mix).

Legumes are popular among many cover crop users because they fix nitrogen in the soil, among other benefits. Crimson clover led the legume category in average acreage per user, followed by winter pea, hairy vetch, other clovers, cowpea, red clover, other vetches and sunn hemp.

Cover crops have traditionally been planted after harvesting cash crops. However, many farmers have found that seeding cover crops into growing cash crops can provide a vital head start in establishing the covers.

by Tara Maxwell

Tara Maxwell is managing editor of Acres U.S.A. magazine. She is a graduate of Virginia Tech with a background in journalism and animal science and a passion for sustainable farming.

Interview: Author Judith Schwartz Examines Water Management

Modern Water Wisdom

Interviewed by Tracy Frisch

When writer Judith Schwartz learned that soil carbon is a buffer for climate change, her focus as a journalist took a major turn. She was covering the Slow Money National Gathering in 2010 when Gardener’s Supply founder Will Raap stated that over time more CO2 has gone into the atmosphere from the soil than has been released from burning fossil fuels. She says her first reaction was “Why don’t I know this?” Then she thought, “If this is true, can carbon be brought back to the soil?” In the quest that followed, she made the acquaintance of luminaries like Allan Savory, Christine Jones and Gabe Brown and traveled to several continents to see the new soil carbon paradigm in action. Schwartz has the gift of making difficult concepts accessible and appealing to lay readers, and that’s exactly what she does in Cows Save the Planet And Other Improbable Ways of Restoring Soil to Heal the Earth, which Elizabeth Kolbert called “a surprising, informative, and ultimately hopeful book.”

For her most recent project, Water in Plain Sight: Hope for a Thirsty World, Schwartz delves into the little-known role the water cycle plays in planetary health, which she illustrates with vivid, empowering stories from around the world. While we might not be able to change the rate of precipitation, as land managers we can directly affect the speed that water flows off our land and the amount of water that the soil is able to absorb. Trees and other vegetation are more than passive bystanders at the mercy of temperature extremes — they can also be powerful influences in regulating the climate.  

The week after this interview was recorded, Schwartz travelled to Washington, D.C., to take part in a congressional briefing on soil health and climate change organized by Regeneration International. As a public speaker, educator, researcher and networker, she has become deeply engaged in the broad movement to build soil carbon and restore ecosystems.

ACRES U.S.A. Please explain the title of your book, Water in Plain Sight.

JUDITH D. SCHWARTZ. The title plays on the idea that there is water in plain sight if we know where to look. It calls attention to aspects of water that are right before us but we are not seeing. By this I mean how water behaves on a basic level, not anything esoteric.

ACRES U.S.A. How should we reframe the problems of water shortages, runoff and floods?

SCHWARTZ. Once we approach these problems in terms of how water moves across the landscape and through the atmosphere, our understanding shifts. For example, when we frame a lack of water as “drought,” our focus is on what water is or isn’t coming down from the sky. That leaves us helpless because there’s really not much we can do. But if we shift our frame from drought to aridification, then the challenge becomes keeping water in the landscape. That opens up opportunities. Continue Reading →

Soil Organic Matter: Tips for Responsible Nitrogen Management

For soil organic matter to work the way it should, it depends on a careful balance of nutrients and minerals, including one of

Healthy, homegrown carrots in rich soil.

the most important elements — nitrogen. One of the great paradoxes of farming is that lack of nitrogen is regarded as one of the great limitations on plant growth, and yet plants are bathed in it because the atmosphere is 78 percent nitrogen.

Most plants cannot use nitrogen in this form (N2) as it is regarded as inert. It has to be converted into other forms — nitrate, ammonia, ammonium and amino acids for plants to utilize it.

In conventional agriculture most of these plant-available forms of nitrogen are obtained through synthetic nitrogen fertilizers that have been produced by the Haber-Bosch process.

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High-Quality, High-Yielding Crops: Measure to Manage

High-quality, high-yielding crops are the goal for most farmers. But where do you begin? Some even insist that to have both is simply impossible to accomplish. For those who think that way, it will likely always be true. But for those who are looking for ways to improve and believe there is still room to do so, what should be considered first? And then where do you go from that point to make the most possible difference?

The soil’s physical structure can be measured and needed corrections determined by use of a detailed soil analysis.

To get high-quality, high-yielding crops, begin with the soil where they will be growing by performing the closest examination of all the most important factors needed to meet every possible requirement. What provides the most advantage to the crop from that soil? Some will feel the answer here is a heavy fertilizer program for the crop. Sufficient fertilizer is extremely important, but to achieve high-quality, high-yielding crops, there is another requirement that is also essential to assure the greatest value from whatever fertilizer is applied.

For each soil to perform at its best requires a balance of water, air, minerals and organic matter. Specifically, if you want the soil to do its best it should contain a balance of 50 percent solids (ideally 45 percent minerals and 5 percent humus) and 50 percent pore space (composed of 50 percent water and 50 percent air). This is the correct physical composition of extremely productive, high-performance soils. To be consistently efficient it is a necessary requirement to develop the most effective biologically active environment to build the needed extensively developed root systems of high-quality, high-yielding crops.

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Soil Testing Based on Mehlich III Extraction Methods

Soil testing, wrote Jerry Brunetti in 2009, is the foundation for the actions you take to add fertility to your soil:

A farmer starts to test the soil.

I’ve always been a fan of foliar nutrition, especially on forages. However, I don’t advocate the application of foliar fertilizers as a replacement for sound agronomic practices involving comprehensive soil analysis (including multiple trace elements), tissue testing, and an evaluation of the soil ecology.

A soil test can be quite easy to interpret and recommendations can just as easily be made based on the results of the test. Since many articles on soil fertility have been written for Acres U.S.A., this article will provide the reader with an “ideal” test based upon a Mehlich III Extraction.

Forage tests generally determine whether or not you are on target with adequate feeding of the crop and are becoming considerably more revealing than in the past. This is especially true in the measurement of total digestibility and fiber digestibility, protein quality, and the various fractions of energy such as sugars, starches, digestible NDF, etc.

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Healthy Soil, Defined

What is healthy soil? Most farmers strive for a healthy, fer­tile soil that has good tilth. But do these terms — soil health, soil fertility and good tilth — all mean the same thing to all of us? I bet you have an image in your mind of what the soil and the crop grow­ing in it should look like. But in today’s

A worm comes up from the earth.

world, with all the available technology, plant protective fungicides, insecticides, etc. along with plenty of soluble nutri­ents, looking at a “good” crop can be deceiving. It may in fact be wearing a lot of ‘make-up,’ covering up its true state of health. In recent years, the USDA Natural Resources Conservation Service (NRCS) has started to focus more on soil health and what constitutes a “healthy” soil.

If we define soil health using the NRCS’ definition, it is “the capacity to function.” I thought about this definition for quite some time and decided I need­ed to add to it, clarifying the thought as “the capacity to function without inter­vention.” I define intervention as plant alterations, fungicides, insecticides, etc. Healthy soil should produce healthy crops without intervention.

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