Andrew McGuire

Cover the Soil for Quick Benefits

Posted by Andrew McGuire | October 16, 2013

As noted in colleague Chad Kruger’s informative posts about soil carbon sequestration (1, 2), it takes a long time to reap the benefits of building up soil organic matter. There is, however, a quick way to improve the function of your soil; keep it covered with crop residues. Read more »

Forego a Hamburger, Feed a Person

Posted by Andrew McGuire | September 5, 2013

I eat meat. More specifically, I eat feedlot beef from major supermarket chains and generally enjoy it. Nonetheless, the implications of a recent study have me questioning whether I will eat meat in the future. Read more »

Change your crop, change your soil

Posted by Andrew McGuire | August 9, 2013

When I was a college student, almost every ag-related class I took mentioned the benefits of the “rotation effect” (better yields, fewer pests, etc.). However, aside from insect pests, how the “rotation effect” actually worked was always taught in only general terms, especially when it came to rotation effects in the soil. Recently, however, genetic methods are allowing soil scientists to begin to see what happens in the soil when a crop is grown. In their paper, Comparative metatranscriptomics reveals kingdom level changes in the rhizosphere microbiome of plants, Turner et al. describe the genetic tool they used, metatranscriptomics, and how they used it to get an “initial comprehensive picture of the [soil] community structure” in the plant rhizosphere. Read more »

Study Shows Soil-Building Benefits of Manure and Crop Rotation, so why didn’t they say so?

Posted by Andrew McGuire | June 27, 2013

Here is the secret to building soils – manure and diverse crop rotation. Underwhelmed? Researchers in Iowa (Delate et al, 2013) came to this conclusion after conducting ten years of field research. Only this wasn’t their conclusion.

“Iowa State study shows soil-building benefits of organic practices,” reads the headline of the Leopold Center press release on this research. This is misleading for two reasons. Read more »

Are You Micromanaging Your Soil?

Posted by Andrew McGuire | May 21, 2013

mi·cro·man·age: to manage or control with excessive attention to minor details.

As a means to improve soil management, I commend the high interest in soil biology among farmers and gardeners. However, I have noticed the tendency for this interest to be combined with the thought that we should be able to fine-tune our soil biology for the good of our crops, health, sustainability, democracy, justice, and peace.. OK, mostly just crops and soil health, but exaggeration does seem to be rampant when it comes to expectations. The problem is that the idea that we can accurately fine-tune our soils is wrong. Unfortunately, this has not stopped a swarm of salesmen from swooping upon budding soil micromanagers hawking their bio-products. And this is not just at organic farming conferences where biological products are commonplace. I collected this list of products at last year’s Pacific Northwest Vegetable Association conference in Kennewick: Bio Secure, Bio Safe, Bio Innovator, Bio Flora, Bio Generator, Byo Soil, Byo Gon, Bio Forge, Bio Works, Bio Terra Plus, and BioBurst. Read more »

Mixing the Perfect Cover Crop Cocktail

Posted by Andrew McGuire | April 17, 2013

Last November, at the WSU Building Soils for Better Crops conference, farmers from Kansas, North Dakota, and Colorado all spoke on the benefits they were seeing from using multi-species cover crops. These cover crop “cocktails” consist of 8 or more species chosen to maximize diversity. Cocktail mixers aim for at least one entry from each of the following categories: warm season broadleaf species, cool season broadleaf species, warm season grasses and cool season grasses. In addition to the benefits regularly associated with cover crops, farmers using these cocktails often point to increased crop yields and reduced inputs as the reasons they are using them. These cocktails also seem to give rise to a passion not seen in farmers using single-species cover crops.

So, what is going on here? Read more »

No-till Does Not Reverse Soil Degradation?

Posted by Andrew McGuire | March 14, 2013

A recent paper (Olson, 2013) finds a number of long-term studies were wrong about no-till practices building soil organic matter and thus sequestering carbon.  The problem, says Kenneth Olson, soil scientist at the University of Illinois, is how the studies in question measured the gains or losses in soil organic carbon (SOC; organic carbon is about 50% of soil organic matter by weight). According to Olson, these long-term studies made soil carbon measurements during or at the end of the experiments which compared the results of no-till (NT1 in figure 1) to moldboard plowing (MP). They then concluded that carbon was sequestered in the soil under no-till but not in tillage systems. The figure below represents what Olson says these studies measured. Read more »

Filed under Climate Change, Sustainability

Hamstrung by Ideology

Posted by Andrew McGuire | December 20, 2012

Last summer, I visited an organic farm in the area. The farmer showed me various parts of his operation, one of which was a field that he had planted to a species of perennial grass that produces an abundance of deep roots. We dug a hole and confirmed it; a dense fibrous root system had formed after two years of growth. The farmer’s goal in planting this grass was to build up the soil before vegetable production. When I talked to the farmer again this fall, he was trying to figure out how best to go from the grass to vegetables. There could be two options for doing this. Read more »

Filed under Organic Farming, Sustainability

How to kill your soil

Posted by Andrew McGuire | November 1, 2012

I recently saw an infographic that stated, “There are no life forms in the soil, which is sterilized…” What was it talking about? Soils on the moon?  A toxic chemical spill? Soils around Chernobyl? Nope, this was the description of soils under industrial agriculture. I have heard it before, the epidemic of “dead soils” caused by “chemicals.” This may make good copy for organic food advertisements, but it is not good science. Read more »

Filed under Sustainable Practices and Technology
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Organic Farming Reliant on Synthetic Nitrogen

Posted by Andrew McGuire | October 9, 2012

A number of studies have recently suggested that organic farming better addresses issues related to climate change than non-organic farming. Many of the reported climate change advantages of organic farming flow from its prohibition of synthetic fertilizers and exclusive use of organic fertilizers. In the debate over the future of agriculture, organic food proponents have been using these results to support their arguments. One such recent statement is found in the Organic Farming Research Foundation’s August 2012 publication Organic Farming for Health and Prosperity which states “…organic farming has been shown to effectively mitigate climate change by increasing carbon sequestration in the soil, reducing greenhouse gas release and consuming less fossil fuel.” In comparison to non-organic farms, most of the climate change mitigation benefits of organic farms “were due to the high energy demand and emissions associated with the production of synthetic fertilizers used in the non-organic system.” Since organic farming uses organic sources of plant nutrients, like animal manure or fish byproducts, it disassociates itself from the energy inputs and greenhouse gas production associated with synthetic fertilizer production, or does it? Read more »

Filed under Climate Change, Organic Farming, Sustainability

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