Healthy soil and sustainable growing

["Tradingpost" <tradingpost@lobo.net>]

I've got a lot to say about this - anyone want to jump in?

paul tradingpost@lobo.net


*********** REPLY SEPARATOR  ***********

On 5/3/2010 at 9:04 PM Tradingpost wrote:

>Why Planting Farms in Skyscrapers Won't Solve Our Food Problems
>'Vertical' farming would not solve the most pressing agricultural problems
>-- just make things worse.
>May 3, 2010  |
>http://www.alternet.org/food/146686/why_planting_farms_in_skyscrapers_won%27t_solve_our_food_problems?page=entire
>
>Agriculture in America has become an ecological, social and nutritional
>disaster of sufficiently huge scale to inspire a frenzy of book-writing,
>filmmaking, conference-holding and project-initiating in recent years. The
>critiques that emerge are often right on the money, highlighting pesticide
>and nitrate pollution, soil erosion, the consequences of meat production
>in feedlots and confinement sheds, the destruction of rural communities
>and the poor nutritional quality of food. But the solutions being proposed
>have not, for the most part, been of the same scale as the problems; most
>would do little more than nibble at the edges of America's long-running
>agricultural fiasco.
>
>A striking example of such ill fit between problem and proposed response
>can be found in the November 2009 issue of Scientific American, where
>Dickson Despommier, a professor of public health and environmental health
>sciences at Columbia University, made his case for what he calls "vertical
>farms," a vision he promotes through his site verticalfarm.com.
>
>After doing a very good job of describing the terrible toll that
>agriculture takes on soil, water, and biodiversity across the globe,
>Despommier's article lays out a proposal to replace soil-based farming
>with a system of producing food crops in tall urban buildings-to, he
>writes, "grow crops indoors, under rigorously controlled conditions, in
>vertical farms. Plants grown in high-rise buildings erected on now vacant
>city lots and in large, multistory rooftop greenhouses could produce food
>year-round using significantly less water, producing little waste, with
>less risk of infectious diseases, and no need for fossil-fueled machinery
>or trans¬port from distant rural farms."
>
>Despommier describes how one of his scenarios-which are based on the use
>of hydroponic or "aeroponic" methods of growing plants without soil-might
>work: "Let us say that each floor of a vertical farm offers four growing
>seasons, double the plant density, and two layers per floor-a multiplying
>factor of 16 (4 _ 2 _ 2). A 30-story building covering one city block
>could therefore produce 2,400 acres of food (30 stories _ 5 acres _ 16) a
>year." By extrapolating numbers like those and assuming extraordinary
>leaps in technology, as well as the repeal of Murphy's Law, he has made
>such a convincing case for vertical farms that, he claims, "many
>developers, investors, mayors and city planners have become advocates."
>Time magazine has run a generally positive story on the concept. And an
>Australian architect is currently planning to build the first full-scale
>vertical farm, in China.
>
>The idea for vertical agriculture grows out of the realization that there
>are not enough exposed horizontal surfaces available in most urban areas
>to produce the quantities of food needed to feed urban populations.
>Although the concept has provided opportunities for architecture students
>and others to create innovative, sometimes beautiful building designs, it
>holds little practical potential for providing food. Even if vertical
>farming were feasible on a large scale, it would not solve the most
>pressing agricultural problems; rather, it would push the dependence of
>food production on industrial inputs to even greater heights. It would
>ensure that dependence by depriving crops not only of soil but also of the
>most plentiful and ecologically benign energy source of all: sunlight.
>
>Groping in the dark
>
>Agriculture as it has always been practiced-call it "horizontal
>farming"-casts an extremely broad, green "net" across the landscape to
>capture solar energy, which plants use in producing food. Photosynthesis
>converts a small percentage of the solar energy that falls on a leaf into
>the chemical energy in food. But that small percentage is enough; sunlight
>is plentiful, and left to themselves, plants do not have to rely on any
>other sources of energy to grow and produce.
>
>Nevertheless, modern agriculture has managed to make food production an
>energy-losing proposition. Its emphasis on increasing yield per unit of
>land and per unit of human labor has meant a sharp increase in the input
>of fossil energy-with farms often using more energy to produce the food
>than is contained in the food. Some of the most notorious features of
>factory farming are dark, dank hog and poultry confinement operations;
>now, Despommier's plan would create plant-confinement operations as well.
>
>Most of the attention that vertical farming has received in the media has
>been embedded in the context of rooftop gardens, greenhouses, and "green"
>high-rise facades (pdf). But those methods for growing modest amounts of
>relatively expensive food (usually vegetables) differ from Despommier's
>plan to "farm" the interiors of buildings in one important respect: they
>are at least capable of capturing solar energy efficiently.
>
>For obvious reasons, no one has ever proposed stacking solar photovoltaic
>panels one above the other. For the same reasons, crop fields cannot be
>layered one above the other without providing a substitute for the
>sunlight that has been cut off. Even with all-glass walls, the amount of
>light reaching plants on all but the top story of a high-rise would fall
>far, far short of what is needed. (On a sunny day, a room with plenty of
>windows may look well-lit to our eyes' wide-open pupils, but that light
>intensity is a tiny fraction of what is needed for crop production.) A
>significant portion of the light hitting the building would be turned back
>by the glass, and direct sunlight would penetrate into the interior of a
>vertical farm only when the sun is low in the sky (especially if, as
>Despommier recommends, two layers of plants are stuffed into each story.)
>Even then, it would reach the crop plants at a low angle, so that each
>square inch of leaf would receive much less light than if the light were
>hitting the leaf from above.
>
>As a result, the lion's share of a vertical farm's lighting would have to
>be supplied artificially, consuming resource-intensive electricity rather
>than free sunlight. This led us to wonder, "What would be the consequences
>of a vertical-farming effort large enough to allow us to remove from the
>landscape, say, the United States' 53 million acres of wheat?" That's not
>an unreasonable question. In fact, it follows from Despommier's own
>reasons for promoting the practice. He argues, correctly, that soil is
>currently being abused on a massive scale; therefore, to address the
>problem, vertical farming would need to displace agriculture from a large
>proportion of the currently cropped landscape.
>
>Our calculations, based on the efficiency of converting sunlight to plant
>matter, show that just to meet a year's U.S. wheat production with
>vertical farming would, for lighting alone, require eight times as much
>electricity as all U.S. utilities generate in an entire year [see
>calculations here]. And even if it were energetically possible, growing
>the national wheat crop under lights could substitute for only about 15
>percent of US cropland. Were it to succeed, that energy buildup of
>unprecedented scale would still leave 85 percent of cropland in place.
>
>Despommier suggests using renewable sources to supply the power needed for
>vertical farming but fails to consider the scale-up that would be
>required. Wind, solar, biomass, geothermal, and other renewable
>electricity sources combined account for about 2% of U.S. generation. So
>to grow the national wheat crop vertically using renewable sources would
>mean scaling up the nation's renewable sector by 400-fold just to run the
>lights! (His proposals for doubling plant density, using round-the-clock
>light, or pushing year-round production, even if they could be made to
>work, would increase production per unit of area but would not decrease
>the energy needed for lighting per unit of food produced.)
>
>One of our colleagues suggested, with his tongue in cheek, an alternative:
>"What about vertical nuclear energy? We could stack reactors in
>skyscrapers alongside the farming skyscrapers, to provide the
>electricity!" Fortunately, no one's going to try that, because just to
>grow our wheat. we'd have to add another 4000 or so nuclear reactors to
>the hundred or so currently in the United States.
>
>To have a much greater impact on soil conservation efforts than the
>displacement of wheat would accomplish, we'd want to take indoors the
>nation's number-one grain, corn, which occupies about a quarter of our
>cropped acreage, and some of the most badly abused land. But corn makes
>wheat's electricity consumption look modest. Because wheat naturally grows
>mostly in fall, winter, and spring and produces lower yields than summer
>crops like corn, its light requirement is lower. The U.S. corn crop would
>require energy for lighting equivalent to 40 times the current US
>electricity supply.
>
>Maybe trying to satisfy the nation's huge grain requirements with vertical
>farming is too ambitious. Assume instead that we were to take a more
>modest approach and grow the national crop of vegetables under lights. If
>that required a similar level of lighting per unit area to that used for
>wheat, we would "only" have to double our national electricity generation.
>But removing all vegetable production from the landscape would preserve no
>more than 2 percent of our currently cropped soils.
>
>A question of control
>
>Based on its energy requirements for lighting alone, vertical farming
>would be incapable of substituting for a substantial share of our
>soil-based agricultural production. But the lighting problem is only the
>first among many obstacles facing high-rise agriculture. Climate control
>to achieve suitable growing conditions would add huge energy requirements.
>And light fixtures would release more energy as heat than as light, which
>in summer would put huge loads on air-conditioning systems. To maintain
>the good health of plants grown indoors, humidity and air circulation must
>be very precisely controlled, often at a high energy cost. And before any
>of those needs would come the gargantuan resource requirements for
>construction of the towers themselves.
>
>Then there would be the impracticalities and energy requirements for
>producing and hauling artificial growth media, fertilizers, water, and
>other resources hundreds of feet up and getting harvests out of the
>towers. Pesticides could not be eliminated and would undoubtedly be
>applied in many situations. If Despommier has ever worked in a greenhouse,
>he knows that some of the pathogens and insects that damage crops in the
>field can be excluded, but that many others will flourish. Powdery mildew,
>aphids, mites, or other pests can easily wipe out greenhouse-grown wheat
>plants, for example, if chemical control is not used.
>
>The system inevitably would also require an enormous input of manual
>labor. As a hydroponic model, Despommier points approvingly to 300-plus
>acres of greenhouses near Willcox and Snowflake, Arizona, in which
>EuroFresh Farms grows vegetables. Energetically, EuroFresh has no
>relevance to vertical farming, because it is a horizontal operation that
>makes good use of Arizona sunshine. But with four employees per cropped
>acre, it does provide a good example of the large manual labor
>requirements of a massive, intensive hydroponic operation.
>
>EuroFresh's geographical location is no accident. It lies close to the
>nation's southern border, and the company employs large numbers of
>immigrant workers. It also employs inmates from a nearby branch of Arizona
>State Prison. If EuroFresh is to provide an encouraging example for
>vertical farming, other questions come to mind. Who will own and control
>the agricultural high-rises? How and from where will the stoop-labor force
>for vertical farming be recruited? What will become of the farm families
>whose central role in the nation's life has been replaced by
>vertical-farming operations? Will they find themselves migrating to the
>cities to tend corporate tomato vines?
>
>The EuroFresh greenhouses can also illustrate some of the pitfalls of
>high-input indoor farming. In April, 2009, the company filed for chapter
>11 bankruptcy, having fallen victim, according to the Arizona Daily Star,
>to "its debt burden, labor troubles and crop pest problems," which
>included invasions of white flies. (EuroFresh emerged from bankruptcy in
>November.)
>
>Alternatives
>
>The solution to soil and water degradation is not to strip food-producing
>plants from the landscape only to grow them, deprived of sunlight, in
>vertical factory farms. Instead, we have to address the Achilles heel of
>agriculture itself: that it has displaced, on a massive scale, diverse
>stands of natural perennial vegetation (such as prairies, savannahs, and
>forests) with monocultures of ephemeral, weakly rooted, soil-damaging
>annual crops such as corn, soybean, and wheat. So far, the weaknesses of
>the current food-production system have been compensated for agronomically
>through greater and greater inputs of fossil fuels and other resources,
>worsening the ecological impact; vertical farming would extend that trend.
>
>The landscape can be saved only through what we might call
>"three-dimensional farming," a system that is arranged horizontally across
>the landscape to capture and use sunlight but also puts down, deep,
>long-lived roots to protect the soil, manage water, nutrients efficiently,
>and help restore the below-ground ecosystems that agriculture has
>destroyed. That will require converting cropland to the production of
>diverse, food-producing, perennial crops. It will mean a reliance on
>natural processes and cohesive rural communities, not technological
>fantasies.
>Stan Cox and David Van Tassel are plant-breeding researchers at The Land
>Institute in Salina, Kansas. Cox's book Losing our Cool: Uncomfortable
>Truths about Our Air-Conditioned World, will be published in June by The
>New Press. This article appeared in the Spring 2010 issue of
>Synthesis/Regeneration.
>
>
>_______________________________________________
>Livingontheland mailing list
>Livingontheland@lists.ibiblio.org
>http://lists.ibiblio.org/mailman/listinfo/livingontheland