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Archive | Soils

Biochar: Prepping it for Soil

Biochar can benefit your soil, but only if properly prepared prior to application. In November 2007, scientists at the USDA National Laboratory for Agricul­ture and the environment (NLAE) in Ames, Iowa, began multi-year field trials to assess the effects of biochar on crop productivity and soil quality. Scientists amended almost 8 acres with biochar made from hardwood. Twelve plots re­ceived 4 tons per acre; 12 were treated with 8 tons per acre.

Author David Yarrow helps install a biochar test plot at Subterra in Kansas.

They found no significant difference in the three-year average grain yield from either treatment. Other USDA field and laboratory studies in Idaho, Kentucky, Minnesota, South Carolina and Texas showed hardwood biochar can improve soil structure and increase sandy soils’ ability to retain water. But soil fertility response was more variable.

USDA scientists violated four key principles for biochar use: 1) bulk char, in one large load 2) raw, uncharged char 3) sterile, uninoculated char, with only a tad of microbial life 4) synthetic salt fertilizer, tillage and other antibiotic practices.

After all, soil may get 25 or more inches of rain a year, but not all at once in a single event. Biochar, like water, is best added in a series of small doses so soil has adequate time to distribute and digest it. We already know from research in the Amazon that dumping five, 10, even 20 tons of raw char all at once into poor soil retards plant growth for one year and maybe two. But after that, plants erupt in impressive, vigorous growth.

But a dip in yield isn’t acceptable for production agriculture. Farmers can’t wait a year or two to harvest a profit­able crop. Professional growers need fast response and strong stimulus to growth. Economics and handling logistics require convenience and low cost, with vigorous growth from minimal applied material.

Fortunately, we are learning how to prepare char for optimum results in soil and on crops. Biochar research in America is hardly 10 years old, but solid research shows that properly prepared, intelligently applied biochar has dramatic effects on soil structure and plant growth at as little as 500 pounds per acre.

To prepare biochar for optimum effec­tive use in soil, there are four fundamen­tal steps: moisten, mineralize, micronize and microbial inoculation. Continue Reading →

Soil Testing: The Need for Total Testing

What many farmers probably don’t know about soil testing is that most soil tests only tell us what is soluble in the soil. They do not tell us what is actually there in the soil, no matter what fertilizer salesmen might like to imply. To find out what is actually there requires a total acid digest similar to what is used for plant tissue analysis. Mining labs run these total acid di­gests on ore samples which are crushed, ground and extracted with concentrated nitric and hydrochloric acid solutions, but a mining assay does not determine total carbon, nitrogen and sulfur as a plant tissue analysis would. These ele­ments need a separate procedure essen­tial for evaluating soil humic reserves.

Total soil testing is key to understanding your soils’ needs.

Most soil tests measure total carbon, which then is multiplied by 1.72 to calcu­late soil organic matter. This assumes that most of the carbon in the soil is humus of one form or another. While this may or may not be true, determining the car­bon to nitrogen, nitrogen to sulfur, and nitrogen to phosphorus ratios is a good guide for evaluating organic matter, and this requires testing total nitrogen, sulfur and phosphorus as well as carbon.

While carbon in almost any form is a benefit to the soil, it helps enormously if it is accompanied by the right ratios of ni­trogen, sulfur and phosphorus. Though these ratios are not set in stone, a target for carbon to nitrogen is 10:1, for nitro­gen to sulfur is 5.5:1 and for nitrogen to phosphorus is 4:1. This works out to an ideal carbon to sulfur ratio of 55:1, and a carbon to phosphorus ratio of 40:1. Because soil biology is very adjustable these targets are not exact, but achieving them in soil total tests is a good indica­tion of humus reserves that will supply the required amounts of amino acids, sulfates and phosphates whenever the soil food web draws on them. Continue Reading →

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.” Continue Reading →

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.

Continue Reading →

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.

Continue Reading →