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Supplying Nitrogen: Tap into Nature

Human activity is affecting planet Earth to such an extent that natural scientists are naming this time the beginning of a new geological age/epoch called Anthropocene (the recent age of man) and ending what was the Holocene epoch (about 17,000 years ago to present).

We are no longer observers of nature, but significant influencers of what is happening to nature. The sheer weight of humans and their livestock is now bigger than the Earth’s wild animal population. Our activities are rapidly increasing the amount of CO2 in the air. That is an established fact, the effect of which is the only thing in dispute, i.e. will it get warmer or cooler and will we be wetter or dryer?

The temporary warmth is obvious in the Arctic. Although growers usually help to absorb CO2 by growing crops, their improper handling of crop residue or improper feeding of livestock can add the CO2 back into the air. However, farming’s bigger polluting effect concerns nitrogen.

Plants have always used N from the air by a variety of natural methods. Now the rate we are taking N out of the air is 50 percent higher than what nature has done for millions of years. Most of this industrially created N is now used for fertilizer. This industrial process was originally used to make munitions prior to World War I.

Taking N out isn’t really the problem; it is the later consequences that matter. Chemical N leaches into the aquifer. We are all familiar with ocean “dead zones” where the oxidized N and P have fed algae blooms that starve aquatic life for oxygen and the concept of “blue babies” that occurs when excess nitrate in the water causes babies to turn blue from lack of oxygen in their blood. Even though people don’t turn blue, they may have, and not be aware of, a reduced amount of oxygen in their blood, which can affect their energy levels.

As growers, we must do our part in mitigating our impact on natural systems by taking every opportunity to use naturally occurring N and cease the use of industrially created N. There are five main ways we can get the nitrogen we need to grow our crops without resorting to man-made N. The good news is that you will be raising healthier, more valuable crops in the process of using nature’s supply of N and can achieve comparable yields (or even greater yields).

Legumes

One of nature’s original methods of building available N is with N-fixing plants called legumes. Legumes range from small white clover to large shrubs and trees. They all have the ability to take N2 gas out of the air that is circulating in the soil and use a biological/chemical process to fix the N2 into ammonium ions and/or more complex amino acid molecules. There is a microorganism called rhizobia that establishes itself inside the root nodule to complete the process.

Since each legume may have need of a different rhizobium it is best to buy the inoculant that matches it the first time you use that particular legume. If you are not farming conventionally/chemically, the organisms will usually survive, and you will not have to keep buying new inoculum for the repeated crop. The amount of N fixed by a given legume varies widely, but 30-60 pounds per acre is common.

The legumes usually need the trace mineral molybdenum to make the process happen efficiently. Hopefully, you all remember to dig up your legume of choice, carefully cut open the visible nodule on the root and check its size and color. The larger the nodule, the more the fixation potential. The darker the pink, purple or maroon, the more molybdenum you have in your soils to make the process work. If you have dull grey nodules, you need to add some molybdenum. The easiest, least costly way is to use fish, seaweed and ocean liquid or dry products that contain traces of “Molly B” on a regular basis.

Azobacter

Nature’s second process of supplying N involves freestanding microorganisms called azobacter or azotobacter.

These organisms don’t have to use a root nodule to change the N2 gas to ammonias and other important compounds. They basically absorb the N2 gas and release ammonias and the other compounds. The other compounds are very significant, including amino acids (the building blocks of protein): glutamic, methionine, tryptophane, lysine, and arginine. This means your plants are receiving N in a form that they can use without expenditure of valuable internal energy that can be used for increased production.

Azobactor also produce vitamins B1, 2, 3, 5, 6 and 12 and vitamins C and E. In addition, the phytohormones indoleacetic acid, gibberellic acid and cytokines are produced. If you add up the cost of buying all the compounds separately, modern azobactor products are a real bargain. Conventional farming kills off these organisms and robs the grower of what amounts to free N and a whole slew of growth factors.

Thanks to a technology breakthrough, cyst forms of azobacter that can operate on a leaf surface to produce ammonias and all the other compounds for uptake by the plant are available in the marketplace. The amount of N produced in the soil and on the leaf is conservatively listed at 40-50 units per pound per acre per application. The azobacter can also deny surface space to disease pathogens. (Believe it or not, “good” nematodes are also great ammonia and amino acid factories.)

Manure

The next major natural source of N is from the waste products of livestock. Stable manure will also contain urine, so now you have ammonias, nitrates, urea and some protein N. Much of this can be wasted if manure is not handled properly.

Manure pits are the most common treatment/process that seeks to save/stabilize the N. However, without peroxide, biology and carbohydrates added to aerate and fix the N, much of it is lost, and odor is a problem.

Composting is the best way for sustainable growers to handle manure as the composting process, when done properly, kills pathogens, stabilizes the N and other nutrients, increases microbial activity, and creates other valuable enzymes, hormones and growth factors. Generally compost is used at 1-2 tons per acre providing 14-28 lb N (cow) and/or 60-120 lb N (poultry) the first year.

There are several ways to preserve more N from your manure when composting. Adding clay improves moisture retention and increases aggregation. Adding KS+, a natural mined acidic mineral, at the beginning of composting (or better yet, at the source of the manure) stops N volatilization, kills pathogens and reduces odors very quickly, and creates better amino acids for easier uptake by plants.

Protein By-Products

The fourth way to get N for your crops is to use a protein by-product: blood, feather meal, cottonseed meal or fish products. Protein nitrogen is composed of amino acids which are available for direct use by a plant without the use of internal plant energy to process them. Comparing protein N to industrially produced N is complex.

First, usually about 80 percent of the applied chemical N is lost either up (volatizing) or down (leaching). Second, research shows that the protein N in fish is equivalent to about five times the amount of remaining chemical N. Simply put, 100 units of chemical N winds up being 20 units used by the plant and that 20 units of chemical N has the equivalent effect of only 4 units of fish protein N. The added efficiency of protein N from fish comes from the additional microbial stimulation of “good guys” like azobactor. Five gallons of a 4-1-1 fish product can get you the same result or better than 400 pounds or 40 gallons of 28 percent.

Humus

The fifth natural source of N for your crops is from recycling previous years’ plants into humus. Humus is the product of plant residue broken down by microorganisms. You can build your humus levels through cover cropping and proper handling of crop residue. The humus-building process is greatly enhanced in biologically active soil.

Humus is produced as either active or passive factions from the plant residue. The active faction feeds your next crop, while the passive faction builds long-term humus levels. The usual figure for the amount of N released by humus is 40 pounds per percent of humus per year.

To be on the safe side, I use a figure of 30 pounds per percent of humus. Research shows that large amounts of chemical nitrogen stimulate microbes to eat plant residue, but the carbon volatizes instead of forming humus.

Another vital and positive side effect of microbial N versus chemical N is that mycorrhizae have a much better chance to do their job of producing glomalin (long lasting carbon compounds) which is the true soil “glue” that gives soil structure through flocculation and enables plants to increase the access of N from the air.

Keeping in mind the usual rule that says it takes a pound of N to produce a bushel of corn, let’s see how much N we can come up with using sustainable methods. We will assume you properly incorporated your crop residue in the fall with carbohydrates and bacteria and added protein N if the residue was brown. You have also planted a mixed legume, grain cover crop to take down next spring. Your current humus reading is only 2.5 percent.

Let’s delineate and calculate N sources and amounts for next year’s corn: Humus (30 lb x 2.5 = 75 lb N); Crop Residue (30-40 lb N); Legume plow down (30-60 lb N); 5 gal of a 4-1-1 fish product (22 lb equivalent N); 250 ml nitrogen-fixing azobacter in the row (40-50 lb N); sidedress fish and azobactor and/or foliar feed azobactor (20 lb N); “A few good nematodes” (10 lb N). And it all adds up to (75 + 30 + 40 + 22 + 40 + 20 + 10 = 236 lb N [low end] or 277 lb N [high end]). Add more to that number if you spread raw manure or compost this fall or next spring.

See? You have enough N to grow at least 200 bushels of corn without one pound of manufactured N! Meanwhile, you haven’t added nitrates to the groundwater, killed off any of your beneficial microbes or burned out your humus with artificial, costly processed N. Please break your high N addiction now! Make sure you handle this year’s crop residue correctly, plant a cover crop and get ready.

By Dr. Phil Wheeler. This article appeared in the December 2011 issue of Acres U.S.A.

Phil Wheeler, Ph.D., is well known in eco-farming circles, having served as a consultant to major growers in the Midwest and beyond for decades. He heads Crop Services International, a Grand Rapids, Michigan-based consulting and eco-inputs supply firm. He is co-author, with Ron Ward, of The Non-Toxic Farming Handbook available online from Acres U.S.A. at or by calling 800-355-5313.

Soil Conservation Yields Economic Gains

Soil conservation practices such as growing cover crops and going no-till can result in an economic return of over $100 per acre, according to a set of case studies jointly released by the National Association of Conservation Districts and Datu Research, LLC.

Cover crops, like tillage radish, can improve soil health and structure.

Cover crops and no-till can limit soil loss, reduce run-off, enhance biodiversity and provide other benefits. Naturally, farmers who are considering adopting these soil conservation practices are keen to know how they will affect their farm’s bottom line.

“These case studies quantify for producers, policy-makers and researchers alike what the economic advantages of using no-till and cover crops are, and why it makes good sense for farmers to try them and for organizations like NACD to support and even incentivize their use,” said Jeremy Peters, NACD CEO. “We have loads of anecdotal data that says conservation practices benefit the land and producers’ pocketbooks, but now we have run the numbers and know how much.”

During the three-year study period, corn-soybean farmers experimented with cover crops and/or no-till, and quantified the year-by-year changes in income they attributed to these practices compared to a pre-adoption baseline. They found that while planting costs increased by up to $38 per acre: Fertilizer costs decreased by up to $50 per acre; erosion repair costs decreased by up to $16 per acre; and yields increased by up to $76 per acre.

The studies also found that with adoption of these soil conservation practices, net farm income increased by up to $110 per acre. Included in the farmers’ calculations was the considerable time they spent attending workshops or searching the internet to learn about no-till or cover crop practices.

“That time turns out to be an excellent investment, when bottom lines start improving,” said Marcy Lowe, CEO of Datu Research, which conducted the case studies in partnership with NACD. “Farmers who switch to these practices can see losses at first. But thanks to these case study farmers who are generously sharing what they’ve learned, that learning curve will speed up for other farmers.” Continue Reading →

Soil Lab Selection

Soil lab selection: How does anyone choose the right laboratory? Aren’t they all the same? Should you send a sample to several different labs and average the results? How do you get the samples to a lab and what is the turnaround time? Some homework needs to be done here.

These are all questions that I hear on almost a daily basis. All labs are not the same. This does not mean that one laboratory is better than another. They all provide a different “menu” of services. It is important to find a lab that provides all of the services that you require. Are you just looking for a soil analysis, or do you also need an irrigation water test or tissue analysis?

Laboratories can also choose from a number of methods or “recipes” to obtain results. Which method would be best for your soil type or crop? “Presentation” of results can also vary greatly from one laboratory to another. It is important that you can read the report and make use of the information it provides. These are all questions that you should consider before choosing a laboratory.

Menu of Services

Packages with various soil parameters are usually available, plus some a la carte choices. This will vary greatly from one laboratory to another. I think we all agree now that there is a lot more to soil than pH. Therefore, look at what is included in the soil package you are requesting. Continue Reading →

Carbon Cycling, Carbon Building

In this article I hope to provide some ideas concerning carbon cycling and how to effectively build soil carbonic organic matter. There seem to be three primary means by which we can increase a soil’s carbon content: carbon imports, carbon generation and carbon induction. Each of these possible methods can also offer other strengths to a soil-building program, compost can provide a biological inoculum, humates can provide a biological stimulant.

Adequate levels of functional organic matter and a robust soil digestive system are sorely lacking in most all agricultural soils. This lack of humic substances and biology significantly reduces a soil’s water-holding capacity and the ability to release nutrients, all of which leads to large losses in crop quality and yield.

Meanwhile, increasingly higher levels of atmospheric carbon or CO2 are being produced by the burning of fossil fuels and land desertification. Carbon sequestration — the term has been thrown around like a rubber ball. What does it really mean for agriculture? How can carbon be stabilized in soils most effectively?

Importing Carbon

There are three primary carbon imports: Humates or leonardite, and their derivatives such as fulvic and humic acids. The humic substances present in these materials generally provide very good nutrient exchange. Biochar is also a stable carbon import but not as active as leonardite seems to be. Compost can also be a viable carbon import with the added benefit of a strong biological component. Compost, however, tends to have a lower level of stable humic substances when compared with other materials. A fair proportion of compost can degrade over a period of a few years. Continue Reading →

Root System Architecture & Nitrogen Management

Researchers questioned whether current improved rice varieties are suitable for organic agriculture. Through an experiment focused on nitrogen use efficiency (organic and inorganic sources) and root system architecture, they concluded that varieties bred for high-nitrogen inputs may not be suitable for organic agriculture — reinforcing the need for varieties to be bred specifically for organic agricultural systems. Here the researchers present their work:

The production and extensive application of N fertilizer to crops worldwide has contributed to major environmental problems due to soil leaching and greenhouse gas emissions that play a large role in ozone depletion. Sustainable agriculture aims to conserve natural resources with the mitigation of climate change, and there is increasing interest to move toward organic agriculture. An important issue regarding the acceptance of organic agriculture is the question of productivity. In addition to readily available ammonium and nitrate ions, the soil of organic agriculture can contain a wide range of organic nitrogen compounds such as peptides, proteins, free amino acids, amino sugars and nitrogen heterocyclic compounds. Continue Reading →

Phosphorus: A Limited Resource

Soil is a living, breathing ecosystem. Just as you and I breathe, soil too re­spires, and we measure that respiration rate as an indicator of microbial activity in soil. While there are large, non-mi­croscopic organisms living in soil such as worms, insects and small mammals, none of them exist by the billions in just a handful of soil except the microbes.

Nitrogen can play a close second in the nutrient race, but in most soils phosphorus is the most limiting nutrient.

There are many scientific classifica­tions for microbes in soil, but from the farmer’s perspective only two catego­ries are relevant. Good microbes (major­ity) and bad microbes (small minority). Good microbes enhance plant growth, and bad microbes cause disease in plants. Of course, things are never quite so clear-cut in nature. Some things can be good under some circumstances and bad under other circumstances. So keep in mind this is a simplification of what are, in reality, very complex interactions.

Our management practices should be refined to support the good (most of the time) microbes and suppress the ones known to cause diseases in crop plants. Diseases are not always caused directly by organisms. Sometimes the balance of the system gets thrown off and something ordinarily not a prob­lem finds a new niche and can become problematic.

Weak plants may also be susceptible to organisms in the envi­ronment that normally would not have much impact on them. For instance, a nutrient deficiency might weaken a plant and lead to susceptibility. The good news is, of the thousands of microorganisms identified in soil thus far, only a handful of those really fall into the bad category. The good far outweigh the bad, and with a little thoughtful management, you can keep it that way.

In the case of good microbes, we can take this a step further and narrow our focus to the most crucial organisms within this group, which are those that provide the macro and micronutrients plants require for growth. The most limiting of these nutrients is typically phosphorus.

Nitrogen can play a close second in the nutrient race, but in most soils phosphorus is the most limiting nutrient, often occurring in quantities a thousand times lower than other miner­als. One of the reasons for this is the high reactivity of phosphorus. It tends to bind to soil particles and complex with metals in the soil. This makes it unavailable to plants even if it is present in the soil.

Continue Reading →