Andrew McGuire

Monoculture vs. Polyculture Part II: “Straight up” beats “cocktails” for cover crop ecosystem services

Posted by Andrew McGuire | June 11, 2015

Cover crop mixtures, known as “cocktails” by some, are being promoted as having benefits over cover crops planted as monocultures. As I described in Part I, I reviewed recent research results to get at the answer to the question, “are monocultures or polycultures better when it comes to cover crops?” I found that, for biomass production at least, monocultures were actually best (see Part I). Now, let’s look at other services provided by cover crops and compare polycultures and monocultures. (See an explanation of monocultures, polycultures, overyielding and transgressive overyielding here)

Is a single-species cover crop or a cocktail mixture planting the best choice? Photos: A. McGuire.

Is a single-species cover crop or a “cocktail” mixture the best choice? Photos: A. McGuire.

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Monoculture vs. Polyculture Part I: “Straight up” beats “cocktails” for cover crop productivity

Posted by Andrew McGuire | June 8, 2015

Planting cover crop mixtures is very popular right now. The practice has a feel-good aspect about it and, buoyed by the ecological theory, it fits with the current “mimic nature” strategy of agroecologists. In a previous blog post I demonstrated how difficult it is to do research on cover crop mixtures. Although difficult, there are intrepid researchers investigating this practice so I decided to see what they were finding. The results call into question the value of cover crop mixtures, as in many situations a monoculture cover crop would both produce more biomass and provide other desired services as well. Read more »

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Ecological Theories, Meta-Analysis, and the Benefits of Monocultures

Posted by Andrew McGuire | May 26, 2015

How do we go about increasing agricultural crop yields? As long as human populations are increasing, this is the primary challenge we face in agriculture. We must do this without threatening our ability to produce food in the future, and, if possible, without expansion of agricultural land (see graph below).

Decoupling of US corn production from area farmed. Data source: US Census Bureau (1975, 2012).

Decoupling of US corn production from area farmed. Data source: US Census Bureau (1975, 2012).

 

(From The Return of Nature; How Technology Liberates the Environment). Read more »

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Space Farming is Science FICTION

Posted by Andrew McGuire | March 27, 2015
The future of agriculture? Photo: A. S. Guerreirinho

The future of agriculture? Photo: A. S. Guerreirinho

It said on the screen, “Bioregenerating Soil-Based Space Agriculture.” The title of the talk was “Beyond Intensification.” The speaker, a prominent researcher and prolific author, someone who I thought would present clear thinking on how, in addition to intensification of current agriculture, we can go about producing enough food for the earth’s growing population.  I glanced around to see if anyone else was astonished.  Space farming, he said, was the next step after agricultural intensification with food coming from the Moon and Mars. “Has it come to that?” I thought.

I am a fan of science fiction, not a costumed, Trekkie-conference fan, but a fan. However, over the years, I have realized that the stories I enjoy most are mostly fiction; the science is often ignored. This is “soft” science fiction, the stuff of most Sci-Fi movies because there is a way to visit distant planets; think warp drives on the Enterprise, a hyperdrive in the Millennium Falcon, and wormholes in Interstellar. Read more »

Agriculture Requires Fertilizer Inputs, and That’s Good

Posted by Andrew McGuire | October 16, 2014
Harvest is an export of nutrients.  Photo: S. Bauer, USDA

Harvest is an export of nutrients.
Photo: S. Bauer, USDA

On a brown, August-dry field in Eastern Washington, a farmer in a combine cuts a 24-foot swath across a field of wheat. The harvested grain then begins a journey, first to the storage bin, then to the local elevator, on rail to a flour mill, by truck to a bakery, by oven to bread, and by car to a home where it is eaten. This is good; our foremost mandate to agriculture is to produce food. However, with this successful export of food from farm fields to nearby and distant cities comes a problem: the nutrients in the bread, the nutrients that we need from food, and that plants need to grow, are now far from the field they came from. How do we replace them?

High yields, which we want, increase the problem.  A typical irrigated winter wheat field will yield 140 bushels per acre; about 5,600 loaves of bread. For a center pivot circle of 100 acres, the nutrients in those loaves amount to 182 pounds of N, 70 of P2O5 and 49 of K2O and smaller amounts of other essential nutrients that do not have to be replaced every year. All this ends up somewhere else (in people’s bodies or in sewage treatment plants); it will not be returned to the field1. Read more »

Can We Save Nature by Improving Agriculture?

Posted by Andrew McGuire | September 16, 2014
An example of land sharing in Tanzania.  Photo: Rod Waddlington

An example of land sharing in Tanzania. Photo: Rod Waddlington

There is an ongoing debate about how to produce food for a growing population without losing more of our wild lands. Two options are being promoted; “land sparing” where production on current agricultural lands is intensified to produce more food thereby sparing the conversion of wild lands, and “land sharing” where agriculture and wild lands are integrated and small producing parcels are intermixed with wild lands. The former strategy is championed in a paper by Phalan et al. (2011) where the authors report that more bird and tree species were negatively affected by agriculture than benefitted from it. A contrary view from Tscharntke et al. (2012) argues that the land sparing view ignores the complexity of the real world, and that the land sharing strategy would produce more ecosystem services. From these two views, a range of options expand, all of which are being researched and debated.  Read more »

Questioning the Value of Soil Quality for the Irrigated Arid West

Posted by Andrew McGuire | August 21, 2014

Grant County potato yield Sign“The Nation’s Leading Potato Producing County” states a sign on I-90 at the Grant County border1. In 2010, Washington potato yields averaged 33 tons per acre, compared to Nebraska at 20.7, Wisconsin at 19.8, and Maine at 14.5 tons per acre (Idaho’s main potato producing counties averages 27.2 tons per acre). And it is not just potatoes; the Columbia Basin produces high yields of corn, dry beans, onions, and many other crops. However, the productive soils in the Columbia Basin often have soil organic matter levels less than 1%, much less than the level considered as adequate for proper functioning, and certainly not high enough to be considered high quality soils. How can such “low quality” soils produce high crop yields, yields higher than other regions with higher soil quality? This paradox highlights a problem with the concept of soil quality; that it does not take into account the soil management practices that farmers employ to overcome problems in so-called “low quality soils” and therefore does not reflect real production capacity of soils, especially in the West. Read more »

Cold + Dry = Winterkill : 2013-14 Winter in Review

Posted by Andrew McGuire | June 18, 2014

Remember last winter? As June warms and temperatures in the 90s are in the forecast, it may be hard to recall, but here in the Columbia Basin, it was dry with a few notable cold spells. That combination of cold and dry can be hard on plants, agricultural and ornamental.

Plants, both annuals and perennials, from wheat to lavender, alfalfa to ziziphus, vary in their ability to survive winter conditions. However, there are three factors that combined to make last winter a “hard winter.” Read more »

The Sustainability of the Columbia Basin’s Irrigation System

Posted by Andrew McGuire | June 2, 2014

Although now teenagers, while in Ephrata’s elementary school my three daughters learned about hydropower generation, electricity and the dams owned and operated by the Grant County Public Utility District. This is good. I believe that people should know where the basics of life come from, so I would tell them at the dinner table that I was glad they were getting a good dam education. Eyes rolled. But earlier this year, when a crack appeared in Wanapum dam necessitating a 26′ drop in water level behind the dam, my girls knew what was at stake; the future of a unique and productive irrigation system.

Wanapum Dam at normal operation (photo: Dept of Ecology)

Wanapum Dam at normal operation (photo: Dept of Ecology)

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Concentrate Organic Matter at Surface to Improve Soils

Posted by Andrew McGuire | April 30, 2014
No-till corn with surface residues (photo: McGuire)

No-till corn with surface residues (photo: McGuire)

Organic matter is the key to soil quality, but building soil organic matter levels can be slow and expensive. There is an alternative. Research shows (Franzluebbers, 2002) many soil functions improve when organic matter is concentrated the top 2-3″ of the soil, and that, for many soils and environments, this may be the most effective way to improve soil quality. Read more »

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Contact Andrew McGuire

Email: andrew.mcguire@wsu.edu