What exactly is sustainability?

sexta-feira, março 16, 2018

Resultado de imagem para agricultura sustentavel

There are many ways to farm sustainably, and many ways to discuss the issue

A lot of recent farm press talks about sustainability. When I look up “sustainable” in Webster’s it says: ‘… a method of harvesting or using a resource so that resource is not depleted or permanently damaged…”
The first time I remember that term used with respect to agriculture was when a respected farmer on Sceptre heavy clay soil said the wheat/summerfallow rotation of the day was not sustainable. To be sure, the old half-and-half rotation was responsible for gradually, but surely, reducing the fertility and productivity of even our best dryland soils.
This photo shows the phosphorus response in a 1958 barley crop near Kindersley, Sask. The blue tinges showing in the “check” side of the 
photo are a result of the photo scanning. Photo: Bob McKercher

Phosphorus, then nitrogen

Phosphorus was the first nutrient to seriously reduce wheat yield. By the 1950s P was a big limiting factor. The photo at the top of this page shows a huge barley response to P for barley planted on summerfallow. The researcher, Bob McKercher, told me that the landowner, Mr. Whatley, never seeded a crop without P fertilizer after seeing the effect.
P fertilizer extended the productivity of the soil, and summerfallow allowed us to suck even more of the nitrogen out of the soil organic matter.
By and by we realized that we could do away with sumerfallow if we adopted zero till, put on enough N fertilizer and included legumes in the rotation.
But the old half-and-half rotation lasted a long time with little or no fertilizer, if a farmer could still live off the smaller yields. It was sustainable, but at at a much lower level of production than newly broken prairie.

Organic farming

Organic farming that relies on summerfallow for weed control and nitrogen mineralization is not sustainable at anywhere near the yield of fertilizer and chemical farming.
Organic farms with livestock, legumes and diverse planting schemes are probably the most sustainable. If markets for organic grain and meat are available at seriously elevated prices, then that system is very sustainable.

Continuous wheat with no fertilizer

Continuous wheat cropping with no fertilizer is sustainable — with herbicides to control weeds, especially wild oats. The Agriculture and Agri-Food Canada station at Scott, Sask., has a small field that has been planted neat (without fertilizer) to wheat for 107 years and counting — at least I hope it is still going. The average yield is about 15 bushels/acre. Nitrogen is the big yield-limiting factor (after moisture) but N in rain and free-living nitrogen-fixing soil organisms are enough for a small yield. At that small yield the “suck” on phosphorus, potassium and other nutrients is small.
It is sustainable, at a very low yield.
There is also the famous Rothamsted station in England where a portion of the Broadbalk field has been continuously cropped to wheat with no fertilizer since 1840. The yield is in the 15 to 20 bu./ac. range.

Two crops, one herbicide

It is my opinion that a two crop, one herbicide (glyphosate) rotation is not sustainable. The rat in the closet is weeds that become resistant to the excessive use of one herbicide. We use plenty of glyphosate even if we use it in-crop only for canola. My 2018 crop is canola and I very much look forward to what glyphosate can do so well for so little cost.
In addition to canola in crop, we make use of spring burn-off, pre-harvest and post-harvest sprays of glyphosate. We use too much already with just one crop that tolerates glyphosate and I also plead guilty to that charge.

Protocols for sustainable agriculture

Various parts of the market chain have been working on a “brownie point” system so a farm can be labeled “sustainable.” I have seen some guidelines that say you must not pull any bush or drain any slough if you want to get the label. In that case they should decommission agriculture in all of the U.K. When the Romans first landed they found little but bush and swamp. They cleared the bush and drained the swamps and made farmland of it.
I suspect that many of these protocols are drafted by folks with little understanding of actual farms. Perhaps I am wrong and some reader will enlighten me.

Beef sustainability

It is with some trepidation that I comment on the affairs of cowboys — stubble jumper that I am. But some of the things I have been reading of late leave me bewildered. Recent communications talk about a “Sustainable Beef Framework.” The tone of the piece is “Hurrah, we finally have it!”
A lead statement is “Even the overview of protocols set out in the Certified Sustainable Beef Framework runs nearly 60 pages.” I can just imagine the excitement that cowboys have reading 60 pages as an “overview.”
Imagine what the full document looks like. And what exactly are they trying to sustain?

Home on the range

Probably the most sustainable form of agriculture we have is the cow/calf ranching operations in the remaining grasslands of southern Saskatchewan and Alberta. Many of those operations are 4th and 5th generations of the same family line so they must be doing something right.
A quick peak at the “our values” section on Saskatchewan Stock Growers Association’s Wesbsite (www.skstockgrowers.com) shows some straightforward “sustainability” statements without a lot of flowery language or complicated protocols.
Environmental Stewardship: they simply state that they will use the grass and water in such a way that it is still there for generations to come.
Animal Husbandry: simply states that if they treat their animals with respect and ethical treatment, the animals will take care of them financially.

Spreading manure

One concern I have about livestock is too much manure spread over too few acres near intensive livestock operations. Many studies show it is easy to have too much of a good thing. At our own University of Saskatchewan a major new livestock research facility is being constructed near Saskatoon. The baseline groundwater monitoring is in place in spades. Modern instruments were installed before construction began.
But, we must also have some basic research to determine how to concentrate the nutrients, phosphorus especially, so that it can be economically applied over many more acres. Part of the equation may be that stubble jumpers like me have to start paying for the P they receive in manure.
There are still way too many acres of phosphorus-deficient soil that are far removed from a manure source. On my little patch I have the eroded knolls well charged with P by moving topsoil and high rate of broadcast P fertilizer. But much of the area could still do with a good dose of manure or other P.
As this column has often stated: 100 years from now folks will look back and wonder why we took so long to figure out how to better use manure phosphorus.

Sustainability: The bottom line

In my opinion, much of the sustainability rhetoric we are hearing is mostly buzzwords, often crafted by folks far removed from a combine cab or a cow herd. Long-winded protocols are much like the Kyoto Protocol and other similar documents — too much verbage and too little common sense.
Rather than such a general buzzword such as “sustainability” we should be talking about specific air, soil, water, plant or animal problems that must be addressed

SOURCE: https://www.grainews.ca/2018/03/14/les-henry-what-exactly-is-sustainable-agriculture/

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