Archives for posts with tag: soil science

It turns out that when I was describing the benefits of crop rotation two weeks ago (see May 4, 2014), I was only half right. The process can be much more complicated—and substantially more advantageous—than merely planting different families of plants in different plots each season. The key is choosing what to plant and the order in which to plant it.

A good example of a more scientific approach to crop rotation is described in an Op-Ed piece by Dan Barber, chef of the restaurants Blue Hill (in New York City) and Blue Hill at Stone Barns (in Pocantico Hills, New York), that appears in today’s New York Times (see “What Farm-to-Table Got Wrong”).

Chef Barber buys his wheat from a farmer in upstate New York. On a visit to the farm, he learned that the wheat is only planted at the end of a four-year cycle of carefully selected crops, each of which performs a specific task for conditioning the soil. The procession follows a basic order which can be modified as soil response and weather patterns dictate.

First up is a cover crop such as mustard, which cleanses the soil and adds nutrients. Next is a legume to fix Nitrogen. Rye follows which, apparently, crowds out weeds (and also “builds soil structure”, although no explanation is given as to what exactly this means). Last to be planted is the wheat, the crop that outsiders (and until recently, Chef Barber) would think of as the whole point of this enterprise.

What is lamentable in the wheat farmer’s case is that the market for what those outsiders might call the off-season crops—the mustard, peas and rye—is scarce. While the wheat commands high, New York City prices, the other vegetables and grains go unwanted and often end up as feed for animals raised as food. Such use is not considered by most experts to be a very efficient use of resources.

Chef’s response to this situation was to develop menu items at his restaurants that incorporate the lesser crops and thereby elevate their stature and, presumably, their price (I hope that he pays his farmer as much for the mustard, peas and rye as he does for the wheat). It’s an elegant solution—a no-brainer, in retrospect—and also a win-win. Really, it’s a win-win-win because not only do the farmer and the chef benefit but the patrons of Blue Hill get tasty meals out of it, too.

So, how might this concept apply to the backyard gardener? Well, I’m not sure about growing an entire planter full of rye or mustard but half of a planter mixed with other like vegetables or grains might work (especially if Chef shares his recipes). And I never feel like we have enough Sugar Snap peas so the year of legumes would not be a problem. The primary issue is space, something we never seem to have enough of.

Maybe the question for me is, where can I put two more planters?

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After returning home from running errands this afternoon, I was surprised to find a voicemail message from the soil testing laboratory.  This is the third year I’ve sent them soil for analysis and I did nothing different this year compared to the previous two years.  What could the issue be?

I gave the lab a call back and learned that they were concerned that the tests I requested might not be appropriate for our soil.  Based on a brief visual assessment of the soil samples and their labels (“East Planter”, “West Planter”, “Ground Level”), and without checking the type of planting for which the soils would be used (as I had indicated on the back of the soil test questionnaire), the lab scientist thought that perhaps I worked for a mall and was checking the soil from its indoor flower beds.  I’m not sure whether to be flattered (or not).

It turns out that the basic soil tests I commissioned are intended for mineral-based soils and use acids to extract the nutrients of interest.   This method is efficient and quick and yields reliable results for total nutrient content.  However, for soils that have very high concentrations of nutrients in mineral form, the observed values may not represent how much of the nutrients are actually available to plants.  For example, a clod of partially decomposed ore may be rich in iron but spinach still won’t grow well in it.

Alternatively, for compost and other soils rich in organic matter, extraction by water solubility is usually employed.  Apparently, this method takes longer and is somehow more complicated (I infer, because it costs much more) but produces values that are closer to what is readily available to a plant’s roots.  I explained our soil’s situation—it is used for a vegetable garden—its composition—it is a mix of compost, peat moss and native soil—and its history—she looked up the previous years’ reports—and weighing this information, she decided the basic tests would be okay.

The soil scientist said that many people are (and here she groped for a politically appropriate word) enthusiastic about adding organic matter to their soil, by which I believe she meant to imply that they add too much.  Looking at our previous reports, however, she saw that although some of our nutrient levels are high (“above optimum” is the lab’s term), the values are not off the charts.  I think she concluded that the total and available concentrations of nutrients in our soil should not be too different.

Looking more closely at our previous analysis results, she liked that our soil pH was in the green zone (6.20 to 6.80) last year and noticed that in our first year (the east planter only, in 2011), our pH was high.  I reported that based on the report, we adjusted the pH by adding elemental Sulfur and that was probably why we were at the proper acidity by the end of the 2012 season.  She was happy to hear that someone actually followed their recommendations.

The lab will start the soil testing tomorrow and I hope to hear back from them next week.