Justifiable Herbicide?
In “No-Till: The Quiet Revolution,” David R. Huggins and John P. Reganold argue for no-till farming as a more sustainable alternative to plow-based agriculture and describe how herbicide use has enabled growers to effectively practice no-till on a commercial scale. I cannot believe that anyone other than the herbicide manufacturers is seriously proposing that flooding the earth with lethal chemicals is any solution to the problems of agriculture. Their effect on humans and other animals is known, and their effect on soil and groundwater is potentially disastrous (even if the Environmental Protection Agency gives out assurances about the latter). Producing enough food to feed the world’s population without harming the earth is a hard question; this is certainly not the answer.
Louise Tremblay Cole
Galt, Calif.
THE AUTHORS REPLY: As we have stated, reliance on herbicides is a weakness of no-till as it is currently practiced. We contend, however, that no-till is a positive step in the evolution toward more sustainable farming. In addition, we support and are actively engaged in research efforts that integrate no-till into strategies that limit or even eliminate synthetic pesticide use, as in organic production.
Tillage exposes fertile topsoil to the ravages of water and wind, resulting in soil erosion rates that are greater than soil renewal rates in many parts of the world. Sadly, this practice imperils worldwide food security and environmental quality. The fall of past civilizations has been “written on the land,” as soil erosion claimed their capacity to produce food. No-till agriculture preserves precious topsoil, bringing erosion rates into line with those of soil formation. But no-till currently comes with the trade-off of using herbicides.
We share Cole’s skepticism about herbicides—not all is known about their impacts—and support science-based efforts to assess the short- and long-term effects of such chemicals as well as other agricultural tools and practices within the guiding precepts of sustainable agriculture. We also share Cole’s concern of feeding the world’s population while protecting the environment. We believe we will not only need appropriate emerging technologies and traditional conservation farming practices but also good government policies, smart business models and social ingenuity to accomplish this.
Universal Units?
In “The Self-Organizing Quantum Universe,” Jan Ambjørn, Jerzy Jurkiewicz and Renate Loll describe how, in looking to reconcile quantum theory with Einstein’s general theory of relativity, they developed a new approach to quantum gravity called causal dynamical triangulations. In this approach, on the smallest scales spacetime has only two dimensions (approximated as a series of triangles), but on larger scales it smoothly transforms to three, then four dimensions (approximated as the triangles constructing curved shapes).
Could this fact mean that quantum mechanics would apply only to particles that experience less than four dimensions and that relativity would apply only to the four-dimensional universe?
If so, there would seem to be no point in looking for a mathematical framework that can join these two pillars of physics.
Howard Wolowitz
via e-mail
Ambjørn, Jurkiewicz and Loll state that “space keeps its overall form as time advances; it cannot break up into disconnected pieces.” How, then, is the expansion of the universe explained by the geometric spacetime structures they describe? Perhaps new pieces keep getting created in between and push away the others?
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8 Comments
Add CommentLouise Tremblay Cole is incorrect to imply in her letter Justifiable Herbicide? that herbicides all have the same known effect ... on humans, animals ... soil and groundwater . For one thing, those herbicides commonly used in no-till to replace the contribution of ploughing to weed control are distinctive in being inactivated and immobilised on contact with the soil.
Reply | Report Abuse | Link to thisSustainability inevitably involves trade-offs in seeking the balance between planet, people and profit. Trade-offs demand valuing some things more than others and assessing risks and benefits.
Ploughing requires considerable use of fuel and is a costly, time consuming operation. In those parts of the world where ploughing is done by animal power or spade work, it is an arduous, drudgerous job. Besides avoiding soil erosion, not ploughing also means that soil organic matter accumulates, so sequestering large amounts of carbon. For instance, the Soil Science Society of America recently estimated that wider adoption of conservation tillage in the US could off-set the annual release of more than 130 million tonnes of carbon dioxide.
Many people will surely never accept the arguments for using herbicides simply because they dont like the concept. Fair enough, but it makes sense to weigh-up the best practical ways currently available with which to farm each and every field, and to constantly look for improvements in all aspects. Lets keep discussing the issues, be passionate, but not over-emotional where it detracts from plotting the best course.
Ms. Cole's response falls within expected parameters for her standpoint. Sadly, she chooses to utilize invective as opposed to reason. I would simply ask if she has seen the clouds of dust that accompany a field being ploughed, has watched the wind strip the topsoil from a freshly turned field, and if she believes that this method of field preparation can be indefinitely continued without causing serious damage to the volume and quality of topsoil in the world's agricultural regions.
Reply | Report Abuse | Link to thisI believe that much of the concern I read here may be more related to chemical fertilizer runoff than herbicide runoff, as herbicides are generally more complex compounds that do degrade over time, with half-lives varying widely depending upon the specific compounds. Chemical fertilizers are longer-lasting by their very nature, as they tend to be more elemental in nature, so any runoff or groundwater infiltration will maintain much of the initial chemical potency included in the original formulations.
I will grant that the issue is complex, but to place a blanket condemnation on herbicide use is shortsighted, as advances are being made. Science should yield more efficient soluitions as time goes by. In the meantime, we must choose among the available options, with a mind toward conserving the topsoil that is truly the cradle of our agricultural life.
Neither you nor I has seen the "clouds of dust" that accompany a field being ploughed, nor have we seen wind strip topsoil from a freshly turned field as ploughing is virtually always done in early spring as soon as the soil has dried just sufficiently to allow tractor work, or in the fall to incorporate harvested crop residue for its organic properties.
Reply | Report Abuse | Link to thisCausaul dynamic triangulation is just a schematic way, by which the dense particle system, i.e. Aether condenses.
Reply | Report Abuse | Link to thishttp://aetherwavetheory.blogspot.com/2008/09/sacred-geometry-and-aether-concept.html
Hi,
Reply | Report Abuse | Link to thisi'm a person who is simply passionate about phy6. i like physics 4 its elegance n stuff.
i'm a phy6 student n would like 2 pursue my career in physics anyway!
i like 2 discuss physics particularly topics like quantum theory, relativity
and much more!
for interesting stuff visit:http://blog.myspace.com/index.cfm?fuseaction=blog.view&friendID=20019115&blogID=415638693 and http://blog.myspace.com/index.cfm?fuseaction=blog.view&friendID=20019115&blogID=436414231
Reply | Report Abuse | Link to thisAs a farmer, I suggest you grow your own food. then grow some extra to use a barter for shelter, fuel and a little more for movie tickets.
Reply | Report Abuse | Link to thisIdiots and idealists. Do me a favor. Starve.
I future, instead of useing herbicides we could go back to the labour work, but instead of labourers we will use robots, image the whole army of robots like from The Matrix, witch harvest our crops ;>
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