Friday, February 8, 2008

Sustainable agriculture

No more written exams! Yeah!!! My last written qualifying exam lasted for 4 1/2 hours, and consisted of 4 questions. Three of them were easily answered using the posts I put up 2 days ago (blogging my study results actually proved useful). Nutrient deficiencies were featured prominently, as was postharvest longevity of flowers. Three of the questions were polished off in about half an hour. I spent, however, 4 (!) hours writing on the first question which came completely out of left field. I received a thick stack of printouts with the draft standards for sustainable agriculture, and had to write 4 papers on these. The standards propose to work towards completely organic production systems, which (among other things) would not allow use of genetically modified organisms (GMOs), and gradually eliminate synthetic chemicals from production systems. I had to write a paper in support of the standards on GMOs, one opposed, one in support of the standards on the elimination of synthetic chemical use, one opposed.

It wasn't easy for me to write these papers. I was forced to treat the issues as black-and-white, which clearly, they aren't. I was not asked to form and write on my own opinion. There are arguments pro and con these standards, and I had to simply separate the pros to put in the papers in support of the standards, and vice versa, put all the cons in the paper opposed to the standards. There was no argument involved, no battle of the mind, no final conclusion to be drawn. That bothered me. Of course, I do have an opinion, and at some point I thought my arguments in two of the papers (those were I argued against my own position) became rather silly.

[Credit: Purdue Agriculture Connections]

In my opinion it is naive to think that the standards will be feasible in large-scale agriculture with our current level of understanding, and our current knowledge on integrated pest management. There were darn good reasons to introduce chemicals, one of them being that without those, you're large-scale monocultures are bound to be destroyed occasionally by a pathogen or pest. This would come at a great price financially, socially, and politically. Although you'll be hard-pressed to find someone who thinks we should apply as many pesticides and other chemicals as humanly possible, it's not too hard to find people who are of the opinion we shouldn't use any at all. However, it is not realistic to think that we can basically maintain current production levels while eliminating the use of all synthetic chemicals and pesticides; they do serve a valuable function in agriculture today.

Organic production can work fairly well on a small-medium scale, but with the level of technology available today, is not yet feasible on really large scale. That's not to say we cannot work towards that. We most certainly can, and we most certainly should, and hopefully at some point in the future we can reach this admirable goal, but we're not quite there yet. Unless we're willing to put the livelihood of producers at risk.

[Credit: Wikimedia commons]

For example, the use of synthetic fertilizers allows us to add, very specifically, the exact amount of nutrients that we need. No more, no less. Replace that with something like cow manure (see picture), and the composition varies from one batch to the next, and you have to apply the whole thing, which also applies nutrients you already have enough of. Let say we have used the scientific knowledge of today to sample the plants in our field, and analyzed the nutrient content of the crop, and determined that it is low in nitrogen, but it has plenty of phosphorus and potassium. These are the 3 macronutrients routinely supplied in synthetic fertilizers (which means they were chemically produced in a factory). Now, we can add synthetic fertilizer containing only nitrogen, and since we know how much is in the plants, we know how much there needs to be, we calculate how much we are likely to loose in the soil because of leaching (even after we make every effort at our disposal to minimize leaching), and we apply the amount of nitrogen we need. We apply it near the plant, so that the roots will have optimal access to the nitrogen we've supplied, and we're careful not to apply it too far from the plants so as not to waste it. Had we instead applied cow manure, we would have had to calculate how much to add to satisfy our nitrogen requirements, but we would also be adding phosphorous and potassium, which our crop already has enough off. We risk overdosing on those nutrients (at high levels, toxicity symptoms become apparent), we waste valuable nutrients, because we don't really need any more, and we unnecessarily contaminate the groundwater with excesses of phosphorous and potassium. Virtually every organic fertilizer has the same problems, having the potential to increase groundwater contamination, and not because the source is organic, does that become any less of a problem. Would you still consider that sustainable agriculture?

You may say, but in floriculture, surely we can do without all those synthetic hormones that you apply to regulate plant height and flowering, like you described here? Surely that is frivolous. The reality of the capitalistic ideas of supply and demand, and consumer satisfaction, dictates that plants of irregular heights, that are not flowering (or not flowering synchronously) at the time of display, will be less desirable than those that are perfectly sized for their container, with a beautiful, abundant display of flowers across the board. Uniformity of the crop cannot be taken for granted in today's floral industry.

[Credit: Dr. Bob's Gardening Tips]

For example, the requirements for size, plant height, number of flowers, and availability of plants for poinsettia (Euphorbia pulcherrima) around December are extreme. On December 24, a poinsettia plant may be worth $12, after the holiday season, it's worth $1. You can hardly imagine all the hoops growers have to jump through to satisfy these extreme demands from consumers. From selection of desirable cultivars, exact scheduling of their crop depending on the growth conditions and how vigorous the cultivar grows, regulating day/night conditions, making sure the temperature is exactly right to prevent growing too much or not enough, application of very carefully calculated and applied fertilizers according to the regulations, scouting and treating for pathogens and pests also according to all the EPA regulations, pinching at the exact right time to allow enough leaves to grow, monitoring growth and applying growth regulators if the plants grow too fast or too slow for the schedule, monitoring and adjusting of the alkalinity, pH, and EC of the growth medium, to packaging, shipment, and meeting deadlines and quality standards of the retailer. The retailer will not buy a crop of poinsettia's that does not conform to the strictest of standards. A plant that is 1 inch over the desired height is practically worthless. So, if you measure your plants throughout the growing process (which growers do), and you see that (some of) your plants are growing too fast, too tall. You get off your butt, follow all the safety requirements, get yourself some cycocel, B-nine, or Bonzi, and do what you need to do to save your investment. If some of your plants are too small, some too large, and others ok, your retailer will send you packing, because you have agreed to X number of plants of Y height all in full bloom on the second Monday in December, and you've delivered a hodge podge.

[Credit: University of Illinois extension]

The value of flowers, more than that of any other agricultural commodity, is extremely sensitive to the presence of a ubiquitous fungus like Botrytis cinerea. A few botrytis or powdery mildew spores on your roses (see picture), and your crop drops to the value of $0. Not spraying, is simply not an option. By the way, B. cinerea is very indiscriminate. It is not very particular about its source of nutrition, and it spreads very easily, all the nice little black dots are spores. Millions of them.

[Credit: Cornell University Cooperative Extension]

You've got to be a plant pathologist to say "that's just gorgeous!!" This is reaction not uncommon among my colleagues. A former colleague did not remove a branch from her pear tree for the longest time: "it has such beautiful fireblight symptoms!" I myself, am guilty of maintaining a pot of Magilla perilla, because it was such a fabulous example of downy mildew symptoms (luckily winter decided that I had no right to do so and killed it). All I have left of it are the slides I made and the pictures I took.

But I digress, this is bound to happen once I start talking plant path. I think I've made my point. There are valid reasons to use synthetic chemicals. In an ideal world we would grow all our crops organically. But sadly, contrary to Voltaire's insistence, this is not the best of all possible worlds, and for the immediate future, we're stuck using chemicals. As for the GMOs? That's another post entirely.

5 comments:

ScienceGirl said...

Congrats on finishing the quals!

makita said...

Thank you!

knobody said...

wheeee!!!!

this means you owe me a date! and? this afternoon i have the perfect date. it's 4-7 (not the whole time, that's just the window). i'm buying.

makita said...

Knobody: I'll give you a call later.

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