Heliophage


Perennial wheat progress
October 8, 2009, 10:41 am
Filed under: Farming

Perennial wheat at the Land Institute

A week or so ago, Jeremy had an interesting post at the agricultural biodiversity blog on developments in the field of perennial wheat. Perennial wheat would be cheaper to farm than conventional wheat — less fertilizer, pesticides, sowing costs, tilling costs, etc. The advantages get even greater under some conditions when you look at factors such as increased soil moisture and soil carbon and reduced erosion. So perennialisation of wheat and other crops has lots of fans.

Those fans have to bear in mind, though, that being perennial and still being a proper crop is a hard trick to pull off, as Gary explained some while ago:

It takes great energy to live long and prosper. Stores must be set aside, stored in roots, during the salad days of the growing season. This leaves little energy for seed production since that is a very metabolically costly act. A plant that can do both is a super plant that can suck up water and nutrients with unprecedented skill, capture sunlight like no existing plants, convert sunlight to sugars with unprecedented efficiency, and so have the wealth to set seed in useful quantities while still having enough surplus to set aside energy stores for the lean season and so survive another year.

So you have to expect a trade off between grain yield, and possibly grain quality, and perennialisation.  The study Jeremy points us to, by Lindsay Bell of the University of Western Australia and colleagues, finds that if the perennial wheat is good quality stuff the savings on inputs mean that it could make sense to grow it even if the yield was only 60% of the yield in the annual wheat it was replacing (though obviously more would be nicer). But Jeremy also points to another benefit the research found for mixed farms — that of providing flexibility through growing something that can be used as forage as well as grain.

On a mixed farm that raises sheep as well as wheat, a dual-purpose perennial grain that offers forage, especially early in the growing season, can “greatly increase whole-farm profitability” according to the study. Even if grain yield is only 40% of annual wheat, a perennial wheat would be worth including on 12% of the farm area. The study points out that “this demonstrates that there is capacity to trade-off grain yield for forage production from a perennial cereal”.

Elsewhere in Australia (specifically, in Cowra, NSW, where the cherry-blossom festival just finished) they are embarking on some field trials to see if perennial wheat can actually make it through the summer in a useful way.

Image from wikimedia commons user Dehaan, under a creative commons licence

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2 Comments so far
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Bring it on! Many farmers aim for two or three crop plantings a year, though, which would mean digging up the perennials for the potato or rice planting after the wheat. The only other drawback is that perennials are developed for a specific soil/climate condition – for instance semi-arid. Fine, until, as is expected to be increasingly common with climate change, the conditions radically alter: floods in the semi-arid zone, as is happening now in Karnataka. Then you lose your investment because you lack the flexibility to switch crop. But I guess mixed crop plantings would be worth it.

Comment by Gaia

Good point, WanderingG, but is it really that much of an investment that you lose? Original seeds for perennials probably not hugely more expensive than annual varieties, and so when you need to change crop to something else you can just plough it in — or, better, kill it off with roundup and drill in a new roundup ready cereal of some sort, thus not ploughing and not losing any of the nice soil carbon you’ve stored up. (Needless to say I am not an agronomist and that last bit might be bollocks)

Comment by Oliver




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