The large-scale Organic dairy cooperative, “Organic Valley” has just sunk to a new low in the practice of “I will market against my farmer neighbors by stoking consumer’s fears.” They announced that they have launched an on-line calculator that is supposed to show you how much pesticide and fertilizer use is avoided when you buy their products. The news release essentially boils down to the message, “buy our products or you will probably die!” It also essentially accuses the 97.5% of us who don’t buy Organic of destroying the planet.
When talking about pesticides the press report says: “For adults, exposure through diet has been linked to infertility, Parkinson’s, testicular cancer, birth defects and much more. More than one million children in America age five and under ingest at least 15 pesticides daily. Early exposures are suspected in the sharp rise in health problems including autism, obesity, asthma, brain cancer and other childhood cancers.” This broad-brush assertion is misleading on so many levels that it is hard to know where to start. I’m not saying that there have never been any health issues with any pesticide anywhere, but we also have sufficient food in part because of pesticides. Though many people don’t know it, there are pesticides used on organic crops as well. Actually, the EPA has done a very good job of regulating pesticide use over the years so that people don’t need to be frightened about their food.
Lots of people in America are worried about their food - usually not about having enough food, but mostly about things that might be in their food that could potentially hurt them or their children. People also worry about the environmental impacts of food production. At one level I’m glad that people are engaged in this way and I do believe that there are legitimate concerns. I happen to think that some of the fear about food is misplaced.
I believe that much of this fear stems from a limited understanding of toxicology, molecular genetics, and also what farming is actually about today. Very few Americans have any real contact with farming. Frankly, some of this fear is also driven by the activities of businesses and organizations with a vested economic interest in alarming people.
I’ve been working as an agricultural scientist for 32 years. I’ve had the opportunity to learn about lots of crops grown all over the world. I’ve been involved with all sorts of different technologies. I’ve seen huge changes in agriculture over time. So from all of this experience, do I worry about anything to do with food? Yes, absolutely I do worry! But my list of worries is a little different from the norm
The World Agroforestry Centre has recently released a paper titled ” Trees on Farm: Analysis of Global Extent and Geographical Patterns of Agroforestry.” The researchers used five global geodata sets to estimate the percent tree cover on 22 million square kilometers of agricultural land around the world. They were surprised to find that nearly half of that land had 10% or more tree cover (which is considered “significant” from an agroforestry point of view). The area involved is vast - as large as the Amazon basin.
Even for North America, the percentages were surprisingly high (39% over 10% cover, 17% over 30%). Values in Europe were similar. The highest levels are in central America (98% above 10% cover), South America (81%), and Southeast Asia (82%). Overall, the lowest tree cover is in the most arid areas, but even there >20% of the farmland has 10% tree cover.
The chart above shows the historical average yields for wheat and corn in the US. Note that until the 1930s the relative yields of the crops were similar and were not changing. After that time yields of both crops began to rise steadily, but corn yields have grown at a much faster pace. What explains this difference?
There are several interacting factors behind this, and they work together to create the “orphan” status of wheat as a crop. Corn is a hybrid crop which enhances its yield and the ease of increasing its yield through breeding. Wheat is harder to hybridize so it isn’t practical except for extremely high yielding wheat areas like Northern Europe. Instead, US wheat is largely a “saved seed crop” meaning that the grower can simply save back some of the grain and replant it rather than needing to buy new hybrid seed each year. That system is workable, particularly if the grower periodically buys some “certified seed” to have a purer stand and to take advantage of breeding improvements. The down-side of a “saved seed crop” is that there is not a very big private seed industry to invest in the crop. Most of the breeding is done by University and USDA breeder supported by tax dollars and there is a small private industry as well. As I said in the previous post, these breeders have done a remarkable job with the resources they have, but in an increasingly ag-unaware society, that support is never generous.
I read an article today about a major shortfall in the Kenyan wheat harvest that will drive the need for major imports to meet food needs. There were three major factors behind this disappointing harvest. Tight credit and high energy prices kept some growers from even planting. The rains were not well timed to achieve good yields. Also a new strain of a very serious wheat disease, UG99 Stem Rust, further reduced yields.
This news has nudged me to write a series of posts about wheat because as a crop, it has a lot more problems than one bad harvest in Kenya. The Kenya example just stands as an example of the vulnerability of this extremely important world food crop-a crop that is really an “orphan” in today’s agricultural scene.
A polar bear is the perfect example of “Charismatic Megafauna” - the kind of animal whose image can easily be used to generate sympathy. I care about polar bears as much as anyone, but I’m a little concerned about how images of animals like this are being used to promote Climate Change awareness and to fund-raise for environmental organizations. If we are going to make the personal life-style changes, the new business strategies, and the public policy decisions to counter this threat, we need to do it with a clear-eyed understanding of what is at stake. The “faces” we should be thinking about are those of starving people in poor nations.
Every once in a while I come across something in the scientific literature that really surprises me. Because there isn’t much oxygen in a worm gut, it creates the ideal conditions for these particular microbes (”de-nitrifiers”) to turn nitrate (NO3) into nitrogen gas and also generate some nitrous oxide in the process.
Nitrous Oxide
Ok, some background. Nitrous oxide (N2O) is a very potent greenhouse gas with 310 times the global warming potential of carbon dioxide. Its really an Achilles heel for agricultural sustainability because around 80% of the human-generated emissions of this gas come from farms. If even a small amount of the farmer’s nitrogen fertilizer gets converted to N2O it becomes a major part of the total carbon footprint of that field Read the rest of this entry »
When thinking about “carbon footprints” it helps to have real numbers to put things in perspective. The EPA estimates that for the US, agriculture represents about 8% of total human-related greenhouse gas emissions. The following is a list with a little of the detail of what makes up the footprint of an acre of a rain-fed Midwestern corn crop with a few other things thrown in for comparison. Since we grow 80-90 million acres of corn its something that matters. The values are all expressed as pounds of CO2 equivalents. If you want Carbon equivalents multiply by 12/44
My earlier blog about greenhouse gas emissions from composting generated a lot of good discussion so I am writing to respond.
Yes, composting is certainly better than some outcomes like food scraps going into a garbage dump which does not do anything to capture the methane
Yes, an anaerobic digester would be a very good thing to use for most waste streams. A recent example is what was done at Gill’s Onions
Many wastes can also be put through a fast-pyrolysis process to form syngas and biochar. This is another way to get at the carbon-neutral energy that is in the manure or other waste
Greenhouse gas emissions are not the only metric that matters as was pointed out, but manures in particular are undesirable fertilizers based on multiple other metrics as well: tendency to leach more nitrates because of extended release, more nitrous oxide emissions for the same reason, and excess levels of phosphorus relative to nitrogen leading to water pollution
Compost is indeed a very good way to build soil carbon and that is a super important thing to do for true sustainable farming, but there are other ways to accomplish that that don’t have the greenhouse gas issues. One is the use of biochar. The other is to practice no-till farming and grow cover crops which I describe in another post.
There may be ways of composting that don’t emit as much methane, but I’ve seen far more theoretical arguments that way with no actual measurements taken. As a microbiologist I have a hard time imagining how you could avoid having some anaerobic conditions in a big pile of manure. Starting from 14 times as much carbon equivalents as synthetic nitrogen, the process would have to be vastly improved to be acceptable
Un-composted manure has similar drawbacks as a fertilizer. When it is stored for later use on a farm, at least 1-2 percent of its total methane potential gets released even with very good manure management practices
Chicken manure is more attractive to farmers as a nitrogen source because the levels are higher, but there is every reason to believe it would generate methane in storage and during composting if someone bothered to measure it
Since July 2003, sustainablog has been providing information on environmental and economic sustainability, green and sustainable business, and environmental politics. The blog regularly features environmental leaders, experts in alternative energy and green technology, and real people trying to lighten their environmental footprints.
Sean Daily, 
