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Post by Rob
Hilltop Farm
2012-02-10 00:10:44

Time to Account

It's the “idle” season for farmers and therefore time to look back and assess the productivity of the previous growing-year, if for no other reason than that the IRS wants to know.

At Hilltop, we look at our productivity in some detail at the end of each growing season in order to account to our subscribers what exactly it is they've gotten for the ungodly sum we've charged them.

In looking at the numbers this past year, I was modestly encouraged – not by the fact that Erin and I are still making the same $3 an hour as back in 1993 when I started – but that we had produced more food for our shares in 2011 than we did the previous year. This wasn't much to do with any particular perspicacity or hard work on our part, but more with mother nature giving us better heat and fewer torrential downpours than in 2010. Accordingly, we were able to provide a total of ≈28,580 calories to each of our households over the course of 20 weeks, up more than 11% on the previous year. (This was fortunate, since we had put up prices 9%.) Our members received ≈67 calories per dollar overall. Income per square foot for the vegetable patch – which we account separately from our tree fruits, since the latter provide a much higher return per unit area – eased up over the dollar mark for the first time, to $1.07 / sf. This may have been partly a result of our price increase, but we also managed to squeeze better than 55 calories per square foot out of our garden soil, vs ≈44 cal/sf in 2010. Because we use little in the way of mechanized equipment, we were able to produce just over 10 calories of consumable output for each calorie of non-renewable input for the vegetables, which rises to 13.7 cals when the tree fruits are added in.

I thought I would compare these numbers to those generated by conventional agriculture. Over the years, I'd heard from a few different sources that the generally received figure for farming efficiency in the U.S. is, on aggregate, roughly 1 calorie of consumable output per 10 cals of non-renewable energy input, or a hundred times less efficient than Hilltop and probably most backyard gardeners. This figure presumably includes animal agriculture (which is to say raising them, not farming with them) with its typically higher energy consumption. I was also unclear about whether transport to market was counted in. Since we don't raise animals and don't count the calories we burn driving our shares to our dropsite, I wanted to see if I could find plain old crop-specific, on-farm energy numbers so I could compare apples to apples (literally, in this case).

Such efficiency figures may be out there, but in trolling the internet for several hours I was unable to turn up any. There's a near-infinitude of data on agricultural productivity (bushels/acre, $/acre, lbs/bushel, tonnages by region, etc.) but almost nothing on agricultural efficiency. Champions of the “green revolution” irritatingly conflate the two, an annoyance which brought my blood near to a boil by about the twentieth gushing reference I stumbled across in my search. Sure, if you treat the soil like a widget-machine – extracting nitrogen, phosphorous and potassium from air and rocks, and then pumping them through the soil as fast as you can – you can produce astonishing amounts of food. But the ancillary costs of such mega-scale monoculture – those of climate disruption, soil loss/degradation from heavy machinery, production of poison-tolerant pests (not to say, poisoning the soil itself), the disaster-in-waiting of crazily modified genes floating willy-nilly through the earth's germ-plasm – none of these ever seem to get totted up on the balance sheet. But even leaving that aside, it would be nice to see at least one green revolutionist publish some plain old calorie-in, calorie-out data on crop production before sanctimoniously wagging a finger at us rubes in sustainable ag. Give 'em dead zones in the ocean the size of Rhode Island – which methodology actually produces the most food in the least space for the least amount of energy?

Through a bit of data-mining from various government reports and tapping on the calculator to convert units, I did manage to finally jinn up a comparison between conventional wheat production and the small bit we do at Hilltop (150 square feet or so, enough for 8 or 10 loaves). This was not an ideal example, but data were absent for just about everything else we grow.

From what I could work out, direct on-farm energy consumption for this crop, to my surprise, turned out to be similar for a giant tractor sailing across a thousand acres of Colorado steppe, and our tiny Mantis tiller crawling through the Lafarge silt-loam out back. Though it's a bit hard to estimate, both methodologies would seem to expend about 1.6 calories per square foot. (I did not attempt to conjur the embedded (manufacturing) energy in the multi-ton tractor versus our 20-lb machine, but it surely needs accounting.) Adding in the indirect energy content of synthesized fertilizers (I used national averages for N, P and K, though application rates tend to be higher in the midwest) made the figure jump startlingly, up to ≈11 cal/sf for monocropped wheat (nearly 17 cal/sf in the midwest). I didn't attempt to figure out the add-ins for pesticides. Neither pesticides nor synthetic fertilizers are necessary at Hilltop of course, between composting and obsessive crop-rotation. Wheat produces about 120 cals/sf, so in this case even the big machines would seem to be at least turning out more calories than they are consuming, whatever their downstream impacts on the soil.

But what about numbers for bed-planted lettuces or cabbages or tomatos, compared to their row-cropped counterparts? Wheat is pretty anomalous in its high calorie density per unit growing area, so I'm not sure what generalizations, if any, might be drawn from this example except that better statistics obviously need to be kept. And farmers will probably need to take the lead in collating and publishing these data, since government barely has the money to keep the bridges standing any more, let alone assess the efficiency of agricultural practices. I'd be particularly keen to hear from other farmers who have been tracking their own numbers, or who know if/where any compiled efficiency statistics can be found. I'd also like to know if there is any reckoning on the calorie content of manure or compost, presumably in the form of nutrient bioavailability made possible through the actions of bacteria or other micro-organisms.

After decades of carefully midwifing vegetables from the land and sun, face to face with the soil every day, I'm convinced that hand-agriculture is exceedingly more efficient than the industrial kind. But we need to be armed with real numbers, carefully and transparently assessed, to address the apologists for industrial ag, and in turn demand some realistic accounting of its collateral costs so that we can understand the true price of so much of the world's food. The public may be more moved to source their next meal sustainably once they see the size of the clean-up bill modern ag is handing to their children.