Dear IFPRI
Have you managed to turn groundnuts (Arachis hypogea) into a perennial? Or are you confused perhaps by the difference between perennials and nitrogen-fixing legumes, some of which are indeed perennial?
Your pals
Agro.agro.biodiver.se
P.S. Linking to an article behind a paywall doesn’t make a huge amount of sense either.
It’s nice to know we are into perenniation here in northern Scotland – rhubarb, apples, all the soft fruits, rocket, even hops. But we call it gardening. I despair of people not in Africa – not even growing food – making prescriptions for Africa. Try it out first at home. And remember in drier climates trees use water – lots of it – and perennials are a magnet for dry-season pests and domestic herbivores (which accounts for the great number of toxic or lactiferous perennials in Africa evolved under intense grazing pressure). And if Africa needs perennial crops then where are all the fruit trees you get in South and Central America and tropical Asia? Presumably they are not there for a reason.
Maybe they could be dwarf trees.
Luigi: We already have them. A major source of small-wood in Britain going back to the Neolithic has been from coppice woodland. `Trees’ with rootstocks hundreds of years, with branches from the base, are cut every 10-15 years (giving around 5m poles). This has been a major source of wood for just about every purpose short of heavy timber construction (ships and house frames and the like). The slave trade in East Africa to the Persian Gulf depended on Rhizophora mangrove poles from deltas: if these were cut carefully, the tree would regrow for repeated cutting. I’m off to cut some wood myself before breakfast. The worst September storm for 30 years has downed a lot of mature beech.
I admit the first thing I saw in the IFPRI article was the picture and caption and I immediately slapped my forehead (groundnuts, perennials? doh!). Also, it is a shame that most readers seem to stop at trees and think this is yet another agroforestry article. There are indeed three perenniation strategies presented in the article, only one of which includes trees. Yes, trees use water but if you look at the picture in the article, the tree roots are busting their way through a hard soil layer to access resources that the maize roots would never have on their own. And there is no denying the significant increase in maize yields presented in this article due to perennials.
Luigi, IFPRI has changed the caption to pigeon peas at my urging, FYI, although there are apparently some perennial groundnuts (not mentioned in the Nature article). A simple error was all, not an institutional stance. :)
In terms of Dave Wood’s comment about pests (above), we did cover fairly well the push-pull system exercised in Africa. Please read the article for more… (I have a lot to say about perennials and disease, pests, etc. – an extremely important discussion for which Nature did not permit space – but I will save it for a, hopefully, forthcoming Scientific American article… stay tuned!)
BTW, feel free to email me for PDF reprints in case one cannot access the article from the Internet.
Your (HarvestChoice) friend,
Cindy
c.cox@cgiar.org
Many thanks, Cindy, that’s very kind. I already have a copy of your great article but I suspect Dave would appreciate one. I’ll let him know.
As for the groundnuts, there are some perennial wild peanuts, but I doubt that there are any perennial forms of the cultivated species. Though I could be wrong, I’ll ask my peanutty friends.
Many thanks again for taking the time to respond to our bit of fun. It is good to know someone is listening :)
Luigi
Cindy: My objection to `perenniation’ is not just increased disease in perennial systems (although I remember visiting provenances of Gliricidia in its native homeland of Central America and seeing a nasty little-leaf –a phytoplasma. If vegetative material gets through quarantine to Africa we could have a big problem).
There are at least three groups of problems: of definitions; labour needs; and policy-associated.
On definitions: – the whole concept of `perenniation’ in the `Nature’ feature is flawed. For starters, the article defines perenniation as: `… the integration of trees and perennials (plants that live for two or more years) into fields of food crops.’
This is a new usage and is wrong: the word `perenniation’ has a longstanding different meaning and is used for the various mechanisms by which plants persist through off-seasons (cold or dry): `perennation’ is often used as a synonym. With the simplest search on Google Scholar your usage sticks out, like a sore thumb, as an anomaly. In addition to the persistence of plants themselves `perenniation’ can also be used for plant stands, for example, `One approach being investigated to allow for perenniation of legume cover crops, and thus reduce legume establishment costs, includes natural reseeding systems…’.
Raunkiaer developed an early and exhaustive classification of perenniating mechanisms in 1904. He used the location of the growing point (usually a `perennating bud’) of the next season’s growth. You seem to be promoting only one of his classes – `phanerophytes’, with bud 25cm or more above the ground. Most importantly, at the opposite end of his system, Raunkiaer had `therophytes’ – annual plants where the perenniation mechanism was the seed – and `geophytes’, perennials with the buds at or below ground level on tuber and rhizomes.
Most of our food comes from food stored by plants to enable them to `perenniate’: cereal and grain legume seed from annual therophytes and the roots and tubers of perennial geophytes and certainly not phanerophytes. This has implications for domestication: if pre-agricultural gatherers over-harvested these `perenniating’ food stores the population would die. Management and eventual cultivation and domestication are a solution. However, in contrast, phanerophytes – in particular big trees – can last several human generations with over-harvesting and there is no incentive to domesticate. For example, acorns, from Quercus spp., are or were an important foodstuff. Yet long-lived and perennial oaks have never been domesticated (although important productions systems – as with the dehesas of Spain – depend on acorn production).
A minor point on `evergreen agriculture’: Faidherbia and Gliricidia are (in their natural environments) deciduous and not evergreen. Also Faidherbia is very second-rate compared to Acacia seyal in nitrogen-fixation. Further, Africa already has a perennial grain crop: sorghum growing in river beds draining into Lake Turkana, ratooned every three months and in the ground for up to five years. And if trees improve soil nutrients, then why are soils in tropical forest so nutrient poor?
On labour needs:- trees = roots = hoeing = hard work, mainly women and even children and even = high birth rate to provide family labour. I gardened for four years in semi-arid India in a garden with several fruit trees and surrounded by Eucalyptus. In the first week I broke two tines off my four-tined English gardening fork and went out and bought a hoe. In the pre-monsoon hot season at 45⁰C I could manage perhaps 30 minutes work before heading for shade. Local ladies were hoeing for hours on end – and in Africa, working often with a baby of their back. This is `doubled-up’ agriculture indeed and for this reason alone should be replaced with tractors and fertilizers. Trees and fields do not mix except with traditional management of shifting cultivation and, in Africa, citemene, where trees and bush are turned into ash. But these are low human carrying capacity systems.
The labour demand for research on your usage of `perenniation’ has not been well-managed. At least for agroforestry, the major research base should have been in the Tropical Americas – perhaps in CATIE in Costa Rica – rather than in Nairobi. By design, CGIAR crop institutes were placed in Centres of Origin of their mandate crops (usually) where pests and diseases were most intense and local management knowledge highest; diffusion of results went out from there. On these criteria, the mixed perennial and intercropping systems of Central America are outstanding and deserve more research in-situ. Maize-beans-squash is the classic intercrop; Gliricidia-Cacao and Erythrina-coffee successfully introduce legume trees into plantation systems; and Gliricidia, Leucaena and Calliandra are in the original homes. Further, even with intense research input from ICIPE and Rothampstead, push-pull systems are neither fully understood nor widespread (10,000 farms is less than 0.01% of farms in Africa).
On policy:- with 40% of US maize destined for biofuel and therefore not available for export, Africa urgently needs to increase its food production. The current developed-country focus on biodiversity-friendly and ecosystem-services farming is not an option for most of sub-Saharan Africa. The policy danger is that big, rich, US conservation organizations will come waving their cheque books in attempts to make farming in Africa more `woody’. There are already signs of this. For example, you report that according to an expert in African agriculture at the World Resources Institute in Washington DC, $50 million would be needed even to “show how existing successes [in agroforestry] could be scaled up”. Eco-agriculture and agroecology are other tree-friendly initiatives from the USA (agroecology alone has 30 promotional papers from Berkeley).
This interest, and possibilities of copious funding, from wildlife conservation agencies will not be to make farming more sustainable or productive or even more crop-diverse but to encourage wildlife and, perhaps, turn farmers in Africa into outdoor zoo curators. My view, which you can challenge, is that wildlife conservation has failed – from a predicted range of technical and social reasons and the iniquity of throwing farmers off their land – in the vast protected areas system in Africa. With some degree of sloganeering wildlife conservationists are now turning to farmers and agricultural research to help, inserting their view that `woody = wildlife friendly’, and demanding access to agricultural budgets to preserve wildlife.
In the past I have seen people starving in Africa: for many years into the future we will need every dollar for research into food production (through plant breeding based on still-inadequate crop genetic resources), rather than planting trees in fields to encourage monkeys and Quelea to eat precious crops.