Andrew McGuire

Comparing effects of herbicides, fertilizers, and tillage on the soil

Posted by Andrew McGuire | December 8, 2016
Is this better than an herbicide for the soil? Photo: United Soybean Board.

Is this better than an herbicide for the soil? Photo: United Soybean Board.

In a past post, I argued for the use of an herbicide instead of tillage to kill a soil-building cover crop. My post was mostly observation of the damage of tillage on the soil as compared to the lack of damage, at least visually, from the herbicide. But others suggested that herbicides may not be as benign in the soil as I portrayed them. Here is the latest science on the topic.

A series of reviews have been published on the effects of herbicides on the soil, starting with Bunemann et al. in 2006. They concluded, “The herbicides generally had no major effects on soil organisms.” More recently, a review by Rose et al. (2016) found, “Overall, the majority of papers reported negligible impacts of herbicides on soil microbial communities and beneficial soil functions when applied at recommended field-application rates.” Read more »

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Crop rotation: In praise of deliberate, sequenced disruption of natural systems

Posted by Andrew McGuire | December 1, 2016

For years, researchers have been looking to polycultures, biodiversity in space, as a way to improve agriculture (Trenbath 1974; Tilman et al. 1997; Cardinale et al. 2011; Finney and Kaye 2016). Behind this research is the idea that nature is the best model for agriculture. Because we find that nature is generally a polyculture, we should mimic this biodiversity on the farm. Natural is now viewed as the best option. Today, however, I want to commend a most unnatural practice, crop rotation.

The unnatural, disruptive transition of wheat monoculture to bean monoculture – good for agriculture

The unnatural, disruptive transition of wheat monoculture to bean monoculture – good for agriculture

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The New Urban Indoor Industrial Agriculture… but Why?

Posted by Andrew McGuire | November 16, 2016
Vertical farm crop wall demonstration project. Where is the soil? Photo: State Dept. via Flickr cc

Vertical farm crop wall demonstration project. Where is the soil?
Photo: State Dept. via Flickr cc

There is a new style of urban agriculture appearing around the world. The efforts differ in details, but they all use buildings or structures not originally designed to grow plants – no greenhouses. Carried out in old shipping containers, warehouses, and high-rises, perhaps even in an old factory or two, these “farms” bring agriculture fully indoors. Without sunshine, these farms rely on artificial lights shining on plants 24 hours a day in some cases. Without soil, plants sit in plastic pipes, or float on polystyrene rafts, stacked in tiers.  Without rain, nutrient enhanced water is cycled to the plant roots through piping, pumps and filters. Without wind, fans provide ventilation, ducts and vents deliver heated or cooled air for year-round production.

All this requires energy. These farms are plugged in, reliant on outside power. Outdoor farm fields are off the grid, at least for the production portion of the food chain. Even a continuous corn crop, the scorned example of “industrial” agriculture, is not affected by a blackout. While an outdoor “industrial” crop is still subject to the biological realities of crop growth cycles and seasons, crop production in these indoor farms can be sped up and streamlined. All it takes is lots pipes and tanks, cables and lights. Read more »

The Fallout of October Rains in the Desert

Posted by Andrew McGuire | November 1, 2016
Photo: C. Chene via Flickr cc.

Photo: C. Chene via Flickr cc.

Here in the Columbia Basin, something extraordinary has happened; it rained a lot in October. Although not technically a desert, we are normally desert-like from June-October. Not this year. How much rain did we get? Well, in Ephrata where I live, we have seen over 2.5 inches of rain. I know, not much, even by Inland Northwest standards. But 2.5” is record rainfall for us – never have we seen so much rain in October – and it has had some consequences.

They don’t often admit it, perhaps out of respect for dryland farmers to the East, but farmers in the Columbia Basin prefer to get their water out the end of a sprinkler. They like to control how much and when the water falls on their fields.  When it comes out of the sky, it messes things up. The rains have delayed harvest of late potatoes, onions, dry beans and other crops. Although I expect all these crops will be harvested, the wet ground and crops probably caused some yield losses, and equipment traffic on wet soils likely compacted soils which will require additional tillage to fix.

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Filed under Climate Change, Sustainability
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Defending the Proper Use of Monoculture

Posted by Andrew McGuire | September 27, 2016
Monoculture of dry edible beans. Photo: A. McGuire.

Monoculture of dry edible beans. Photo: A. McGuire.

Many bloggers have it wrong, Wikipedia had it wrong, and when I found that Agronomy Journal got it wrong, I was compelled to write on the topic once again. Monoculture is not the year-after-year production of the same crop in the same field. That is mono-cropping or continuous cropping, where the better alternative is crop rotation. Monoculture is “when only one crop species is grown in a field at a time” (Loomis and Connor, 1992), and the hard-to-manage alternative is polyculture or intercropping. You can take a picture of monoculture, but not of mono-cropping.

Just where this widespread misuse of “monoculture” started, I am not sure. It probably precedes the internet, and may have something to do with the similarity of monoculture and mono-cropping. More recently, Wikipedia played a part. For years it had a definition that combined the meanings of monoculture and mono-cropping. I suspect that this incorrect definition, and the fact that many people without agricultural backgrounds write about agriculture, has led to the widespread misuse we see today. Read more »

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The Benefits of Combining Organic and Synthetic Nitrogen Sources

Posted by Andrew McGuire | June 26, 2016

Dan Sullivan, OSU soil scientist, caught my attention during his presentation at the 2014 Building Soils for Better Crops workshop. Speaking about organic amendments and how to use them for both building soils and for nutrient supply to crops, Sullivan suggested that low nutrient organic amendments, like compost or composted manures, be used in combination with synthetic nitrogen fertilizers. This combo, he said, has benefits over the use of either by itself.

Wheat could benefit from a combination of organic and synthetic nitrogen sources. Photo: USDA ARS

Wheat could benefit from a combination of organic and synthetic nitrogen sources. Photo: USDA ARS

The decomposition that produces compost reduces its nutrient content and stabilizes it. Because it has decomposed some, more of it will end up as soil organic matter than with fresh organic materials. When compost is applied to a field, it will continue to decompose slowly – faster as the soil warms up – releasing a slow stream of nitrogen into the soil solution.  If the compost is being used as a nitrogen source, this flow of nitrogen often cannot keep up with crop demand. One option is to use organic materials with higher amounts of available nitrogen, but these are very expensive; I found a liquid hydrolyzed fish product that could be applied through irrigation water, but it cost $17.76 per pound of nitrogen, over 20 times the price of synthetic fertilizer nitrogen. At this price, these materials make economic sense only for very high value organic crops. This is most likely why organic wheat, a lower value crop than organic vegetables or fruit, produces less grain with lower protein content than wheat produced with synthetic nitrogen fertilizers (Seufert et al., 2012).

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Organic Farming Provides Ecosystem Service and Solves Weed Problems

Posted by Andrew McGuire | April 14, 2016

In nearly all surveys of organic farmers their top priority for research is weed control. Weeds are a tough problem to solve, but with creativity and spunk, researchers in Spain have done it! In their 2016 paper, “Arable Weed Decline in Northeast Spain: Does Organic Farming Recover Functional Biodiversity?” Chamorro et al. provide a unique glimpse into the sort of thinking it will take to move agriculture to a different place. In a series of unanticipated turns, the authors lead us down a path to weed-free agriculture.

First, they contend that weeds are misunderstood. Weeds, as the paper admits, are a bane of agriculture, reducing yields as they do, but in a subtle departure, we are then told “The role of weeds in agroecosystems has been largely debated.” From this debate, the authors conclude that “the role of weeds is manifold”; weeds are not just yield-robbing competitors of crops, they also provide an “ecosystem service.” Read more »

We are the 98%. Thanks to farmers and ranchers, from the rest of us.

Posted by Andrew McGuire | November 25, 2015

Just 2% of our population are farmers. Perhaps this should cause us as much concern as the 99-1% divide (highlighting economic inequality in our country), but today my goal is not warning, but thanksgiving. Here are some observations that we, the 98% should consider about the 2% of farmers, ranchers, growers, producers or whatever they would like us to call them.

Thank you to the producers of our feasts. Photo: Lauren M. via Flickr CC.

Thank you to the producers of our feasts. Photo: Lauren M. via Flickr CC.

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The Essentials of Sustaining Agricultural Production

Posted by Andrew McGuire | July 16, 2015

As a member of the Washington State University Center for Sustaining Agriculture and Natural Resources, I work as an irrigated cropping systems agronomist working on ways to sustain agriculture (a professor I know promotes the use of tee shirts that say “I’m an AGRONOMIST – look it up!”). In doing this, I have come to realize that there are certain requirements that agriculture must meet to produce food and to keep producing food (yes, fiber too, and other non-food products, but mainly we are concerned with food production). I view these as a hierarchy, such that if the top requirement is not attained, the lower requirements do not mean much, but once the top requirement has been met, we can move to the next one, provided that how we do it does not threaten any of the requirements above it. Each component is required, but not sufficient; all of them are needed. Read more »

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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Contact Andrew McGuire

Email: andrew.mcguire@wsu.edu