Discussions regarding organic inputs in sandy soils
(1/9/01 - 1/19/01)

postings: 20
countries: Australia, Costa Rica, Honduras, Ireland, United States, Vietnam
organizations/institutions/companies: Minifarms, CATIE, COSECHA, IFAD, Cornell University

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From: Reid, Aileen
To: MULCH-L@cornell.edu
Subject: Organics on sandy soils
Date: Tue, 9 Jan 2001

Can the collective wisdom of the list please help. Does anyone know of organic farming systems which have been successfully developed on a commercial scale on sandy soils? We are doing some trials with organic systems here in Perth (Western Australia) and our soils are virtually beach sand, very low in organic matter (<0.5%). We foresee our biggest problem as nitrogen - it is hard to supply enough, economically in an organic form. We also have no idea how it is going to cycle. Adding compost is limited to 20t/ha by NASAA and we can see that easily getting burnt up in our summer heat making accumulation difficult.

We are using green manures, together with compost, bloodmeal, fish emulsion etc. But as we are developing it commercially it has to be cost effective. We are aware of the significant organic ventures in California but believe me - our soil (sand) is bad!

Any contacts, advice etc welcome. Although much of what is discussed here is tropical agriculture, I find it good for lateral thinking and have had good help already from members on this list - so please keep it coming!

Aileen Reid
Perth, Austrailia

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From: Karl Gerner
To: MULCH-L@cornell.edu
Subject: RE: Organics on sandy soils
Date: Tue, 9 Jan 2001

Aileen,

The farmers here in Central Vietnam produce vegetables under very difficult conditions. The climate is harsh and the soil is just pure sand (dunes). Once per week they irrigate with a mixture of 1 part slurry from the pig shed and 4 parts of water. The vegetables are doing fine, I was surprised. No idea what this will look like in the long run. The mixture should not get in contact with the leaves, I suppose.

Good luck,

Karl
Vietnam

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Date: Tue, 09 Jan 2001
To: MULCH-L@cornell.edu
From: Donald Kass
Subject: RE: Organics on sandy soils

My father-in-law always tells me that if it doesn't smell bad, it's not good manure. Pig manure is fairly high in nitrogen--I don't know about the other elements. Chicken manure generally has more phosphorus but is a poorer N source. How about bat manure, usually considered the best? If you don't have any bats, just plant some fruit trees and build a shed for them to roost in. When I was in Brazil, farmers would always come to the station to clean the bat manure out of old buildings. Someone told me that organic bat manure sells for something like a dollar a pound in California. Bats are supposedly the only mammalian order to have reached Australia besides the marsupials so maybe you should put the most successful mammalian order to use.

Don Kass
CATIE, Costa Rica

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From: Reid, Aileen
To: MULCH-L@cornell.edu
Subject: RE: Organics on sandy soils
Date: Wed, 10 Jan 2001

Hi,
Thanks for that response. I don't think that would be an acceptable practice under NASAA guidelines however. Unfortunately they require that all manures be composted. But having a whole farm system that can produce its own manures for use in composts is undoubtedly a great help. Most of our vege growers though only grow vege and so have to buy in any composts they use. Obviously a shift in thinking is needed.

Cheers,
Aileen

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From: Minifarms@aol.com
Date: Tue, 9 Jan 2001
Subject: sand
To: MULCH-L@cornell.edu

Aileen,
I have an article in my files about a lady who moved to the coast and I mean literally on the beach. She was a dedicated gardener. She had plenty of sawdust. She mixed 1 part cottonseed meal [N] to 9 parts sawdust and mixed it into the sand. It worked well.

Ken Hargesheimer

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From: Reid, Aileen
To: MULCH-L@cornell.edu
Subject: Sandy soil organics
Date: Wed, 10 Jan 2001

Many thanks to the respondents so far. The use of manures without composting is prohibited under NASAA guidelines. They have to go through a biological process ie composting. Nevertheless that is possible. But also there are limits on the amounts you can use. The ideals of the system are based on the idea of a whole farm system where you use outputs from one part (eg animal manures) in composts for your farming activities elsewhere on the farm. So for example, you are only allowed to import and apply 20t/ha compost per year. Philosophically this is probably supposed to relate to the amount of compost you could produce from a hectare per year. Now, given that organic farming originated in Europe where they have real soil (! :-)), that is fine but in WA where we have beachsand this is a little unrealistic, I feel. Interestingly, in case you don't know, the use of human manures is completely prohibited under NASAA guidelines.

Critics of organic farming, and even myself (who agrees with the philosophy), but as a scientist I have a few problems with trying to come to terms with some of the guidelines of NASAA. As I said earlier, it originated in Europe where they have real soil. Perhaps we should not be trying to farm on our sands at all????? Or maybe we should be trying to bring in a new set of guidelines for growers wishing to farm sandy soils. Most commercial people wanting to convert to organic haven't a snowballs chance in hell of getting any sort of reasonable levels of organic matter within the conversion period of 3 years if they follow the guidelines. There may well be products like humates available, which we probably do need to trial but in the end, whatever they do MUST be economically viable.

Cheers,
Aileen

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From: rolando@cosecha.sdnhon.org.hn
To: Mulch-L@cornell.edu
Date: Wed, 10 Jan 2001
Subject: Org. agr on sand

Dear Aileen,

One thing I'd try would be to plant Canavalia maritima. This is a legume that grows very well on virtually pure sand (I have seen it growing within 20 mts. of the ocean on fairly large dunes in Cuba). It produces a pretty good amount of biomass (I'd guess about 20 T/ha green weight in five or six months). And if the other members of its genus are any indication (plus the good green coloring achieved even on dunes), that will be rich in N (C. ensiformis and gladiata can fix as much as 240 kg/ha of N).

C. maritima could be grown monocropped. But it could also very likely be grown under the rows of medium-sized vegetables, such as tomatoes, potatoes and peppers. We have not tried this with C. maritima, but I do know that farmers in Yucatan, Mexico, are growing jackbeans (C. ensiformis) as a cover crop between rows of chili peppers, with considerable success. In that case they have to prune the jackbeans in order to keep them from shading the vegetables (I can send you specifics on how they do it, if you're interested), but in the case of C. maritima, because of its lower growth habit, it could be you could even avoid the pruning.

In this way, you could possibly avoid most of the composting, transport, etc.

Sincerely,

Roland Bunch
COSECHA, Honduras

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Date: Thu, 11 Jan 2001
To: MULCH-L@cornell.edu
From: Donald Kass
Subject: Re: Org. agr on sand

Dear Aileen and mulchers,
I was going to put in a good word for C. maritima but Rolando beat me to it. I have a picture of it growing on sand in Miami Beach. I don't know how much biomass it produces or where you can get seed but you can always make a seed collection trip to Miami. It is a creeper so it should do well as an understory plant. I don't know how it compares to other Canavalias in terms of insect repellant and Nitrogen fixing qualities. Norris (1959) did report nodulation of C. maritima in Australia (Australian Journal of Agricultural Research 10(5):651-698. It is also used to make floral leys in Hawaii. You might use it to greet tourists when they come to Perth.

Don

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Date: Thu, 11 Jan 2001
To: MULCH-L@cornell.edu
From: kathryn marsh
Subject: Re: sand

Here in Ireland the most productive soil supplying the Dublin market with horticultural produce used to be the dune systems of Rush, Co Dublin. Farmers literally returned from the wholesale market with all the vegetable waste they could lay their hands on and ploughed it straight back in along with seaweed from the beach. That way they got three crops a year since the coastal dunes also lowered the likelihood of frost.

With the move to artifivials the soil rapidly became less fertile and the farms are now mostly under housing with the growth of the city.

kathryn
Ireland

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Date: Thu, 11 Jan 2001
From: Douglas Wholey
Subject: RE: Org. agr on sand
To: MULCH-L@cornell.edu

This topic is very interesting from the standpoint of carbon sequestration. There must be vast areas of sandy soils of low agricultural potential that could be put under more vigorous vegetative cover such as those recently described, and act as a carbon sink. Any comments anyone?

Doug Wholey,
Agronomy Adviser, IFAD.

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Date: Thu, 11 Jan 2001
To: MULCH-L@cornell.edu
From: Donald Kass
Subject: RE: Org. agr on sand

I'm sure the best thing to grow on sand dunes for carbon sequestration are poplar trees (Populus spp.). They grow on the dunes around Lake Michigan but I think there are some tolerant to salinity. They fix plenty of carbon. I know P.deltoides is widely used in Argentina so they must at least tolerate subtropical conditions. Erythrina fusca is a good carbon fixer for lowland soils in the tropics--it also is salt and flood tolerant--and fixes nitrogen to boot. Poplars and Erythrinas can be reproduced vegetatively so you don't even have to worry about seed. There would probably less skin cancer in the world if all beaches were planted with trees too--we might get some opposition from the suntan lotion industry.

Don

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From: Reid, Aileen
To: MULCH-L@cornell.edu
Subject: FW: Org. agr on sand
Date: Fri, 12 Jan 2001

(Quoting Donald Kass)
>I'm sure the best thing to grow on sand dunes for carbon sequestration are
> poplar trees (Populus spp.). They grow on the dunes around Lake Michigan
> but I think there are some tolerant to salinity. They fix plenty of
> carbon. I know P.deltoides is widely used in Argentina so they must at
> least tolerate subtropical conditions.>

(Reid)
We can grow poplars here OK but there is a rust problem so we have to grow resistant vars. They have been used for shelter belts but tend to be a bit invasive root wise.

(Quoting Donald Kass)
> Erythrina fusca is a good carbon fixer for lowland soils in the
> tropics--it also is salt and flood tolerant--and fixes nitrogen to boot.>

(Reid)
There are several species of Erythrina here and they grow extremely well.

(Quoting Donald Kass)
> Poplars and Erythrinas can be reproduced vegetatively so you don't even
> have to worry about seed. There would probably less skin cancer in the
> world if all beaches were planted with trees too--we might get some
> opposition from the suntan lotion industry.>

(Reid)
We also use a lot of Casuarina's - C. cunninghamiana is our best shelter belt tree and there is a native pine - the Rottnest Island pine - Callitris preissi. Not to mention a few thousand species of Eucalyptus, several species and genotypes are being extensively selected for their salinity tolerance. Some of the mallees also produce useful quantities of oil.

Aileen Reid

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From: Reid, Aileen
To: MULCH-L@cornell.edu
Subject: FW: sand
Date: Fri, 12 Jan 2001

Our vegetable growers have built their soils up over a number of years with repeated applications of mostly poultry manure. Again, under NASAA, this can't be used unless composted. Also there is a move here to ban the use of chicken manure and a project on the table to burn it for the generation of power. These growers have 'built' their soils up over 10 or 20 years and they are still very low in organic matter despite this. We still routinely get figures still below 1% after all that time.

Urban encroachment is also a big problem for many of our growers. They are restricted in where they can farm to areas with groundwater supplies and then we have the bogey of all the environmental issues associated with fertiliser/pesticide leaching on sandy soils.

(Quoting kathryn marsh)
> Here in Ireland the most productive soil supplying the Dublin market with
> horticultural produce used to be the dune systems of Rush, Co Dublin.
> Farmers literally returned from the wholesale market with all the
> vegetable waste they could lay their hands on and ploughed it straight
> back in along with seaweed from the beach. That way they got three crops a
> year since the coastal dunes also lowered the likelihood of frost.
> With the move to artifivials the soil rapidly became less fertile and the
> farms are now mostly under housing with the growth of the city>

Aileen Reid

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Date: Fri, 12 Jan 2001
To: MULCH-L@cornell.edu
From: kathryn marsh
Subject: Re: sand

Reply to Reid

As an organic standards manager I frequently find myself insisting on silly standards I have helped design myself to stop some idiot individuals from doing stupid things to their soil - which is what leads to compost everything type rules.

I don't have more than a nodding acquaintance with your standards but surely it is possible to made a very high C compost - probably largely straw based. And surely you are allowed to till back vegetation grown on site without composting it first? What about undersowing with vetches etc and tilling back the whole lot? Have you looked at no-till systems, rolling and direct seeding etc? I suspect that we organic farmers are running behind some of the cutting edge conventional people in this area and there are ways we can use these systems that don't need to involve herbicides. I am no longer growing commercially (back collapsed) but am fortunate that I have a local organic straw source which I use as the basis for my no till system, along with the family's newspaper supply which of course I couldn't use for commercial production. This works equally well on the sand and gravel ridge which is my front garden and the dense, cold, frequently flooded blue clay in my back garden. Both, 20 years on, are deep black soil now.

If you don't know it can I suggest a look at http://www.attra.org/

kathryn

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From: Karl Gerner
To: MULCH-L@cornell.edu
Subject: RE: Org. agr on sand
Date: Fri, 12 Jan 2001

Dear Aileen,
I do not know if trees are an option for you and whether they fit into your production system or not. But on my opinion it is worthwhile to think about it. Here in Central Vietnam the people plant Casuarinas (equisetifolia?) in the dunes. With all their symbiotic microorganisms they grow just excellent in the sand and produce a lot of litter covering the ground.

Karl Gerner
Vietnam

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From: Erick Fernandes
To: MULCH-L@cornell.edu
Subject: RE: Org. agr on sand
Date: Sun, 14 Jan 2001

Greetings all,
Hope you had a peaceful start to the New Year.

Applying organic slurries to sandy soils and sand dunes for cropping is an intriguing approach. Someone once mentioned to me that the Netherlands has 3 t of liquid manure for every inhabitant. Can anyone confirm this? If so, there should be plenty of slurry material for composting!

Having just sampled high clay (Oxisols) and deep sands (Quartzipsamments) in the Amazon, I suggest that for C sequestration, it is going to be much more meaningful to focus on the high clay rather than the sandy soils. To sequester C you have to first fix C via photosynthesis and plant productivity potential is at least an order of magnitude higher in clayey versus sandy soils. In addition, organic matter decomposition rates are much higher in sandy soils. There are several hundred million hectares of degraded, clayey soils currently lying abandoned in the tropics.v Don Kass probably has some interesting C data for the high, volcanic ash (Andosols) in C. America.

Also, the current efforts to drain and settle people in swamp lands around the world will 'swamp' any C sequestration efforts elsewhere. The deep, organic soil found in these areas, is a major C pool and draining these soils results in greatly accelerated decomposition and C loss.

All of the above is moot unless we seriously tackle emissions due to fossil fuel use. Best wishes,

Erick
Crop and Soil Sciences
Cornell University

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Date: Sun, 14 Jan 2001
To: MULCH-L@cornell.edu
From: Quirine Ketterings
Subject: RE: Org. agr on sand

Reply

Erick and others,

I checked the website of the Dutch Department of Agriculture with regards to manure production in the Netherlands. Most recent (complete) data there pertain to 1998. The Central Bureau for Statistics (CBS) in the Netherlands lists for that year a liquid manure production of 51633 million kg. That amounts to about 3.3 metric tons of manure per inhabitant. The total manure production (as opposed to liquid dairy manure) was around 76144 million kg in 1998 (with hog farms being a major producer) suggesting a total manure production of about 4.9 metric tons per inhabitant (estimated yearly nutrient addition in manure of 470 kg N/ha, 135 kg P2O5/ha and 330 kg K20/ha according to CBS). The number of animals has declined in the past decades and continues to decline as a result of nutrient management regulations.

I guess it is true...we may originally have built those dikes to keep the water out but right now...they may be equally functional in keeping the manure in!

Quirine

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Date: Sun, 14 Jan 2001
To: MULCH-L@cornell.edu
From: Donald Kass
Subject: RE: Org. agr on sand

Erick has some very good observations. Should perhaps the mulch group address itself to carbon sequestering--there are certainly ways of using cover crops and fallows to increase C sequestering. I would agree that clayey soils have more prospect. If we believe our colleague Dr. Zech, human activities in the amazon converted Haplorthox soils with about 10 g of organic carbon per kilo to Haplohumox soils (the so called Terra preta do indio) with about 40g of organic carbon per kilo (Zech, W., Haumeier, W. and Hempfling, R. 1990 Ecological aspects of soil organic matter in tropical land use In MacCarthy, C., Clapp, C.E., Malcolm, R.L, and Bloom, P. eds. Humic Substances in Soil and Crop Sciences: Selected Readings. p. 187-202.

American Society of Agronomy, Madison, USA). They also give data of 28.7, 17.7,24.8, 22.0, and 28.7 g kg-1 of organic carbon for secondary forest, young tree garden, mature tree garden, corn field, and compost bed when a typic Chromudert in Yucatan, Mexico was subject to these different land uses. Zech et al. are fairly emphatic that animal wastes function better than plant materials in building up aromatic compounds in the soil which are supposedly more resistant to decomposition. So, animal manures should function better than green manures in increasing soil organic matter in the long run.

I also agree that draining flooded areas and burning fossil fuels will release much more C into the atmosphere than we are likely to fix by carbon sequestering. Has any one ever figured out how much more it costs to maintain a person in a temperate climate than a tropical one? The average American uses 50 times as much of the world's resources as the average Indian, five times as much as the average Italian. Probably less than a quarter of the world's population uses fossil fuel for home heating--but they still manage to release most of the CO2 into the atmosphere. I doubt I would get much support for moving people from the temperate zone to the tropics but it might save energy (if they don't use air conditioning).

I think there is room for some creative thinking in this area.

Don

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From: Reid, Aileen
To: MULCH-L@cornell.edu
Date: Mon, 15 Jan 2001

Steven McCoy Wrote:
> I do not know if trees are an option for you and whether they fit into your production system or not.

Not in our system but certainly for commercial growers, orchardists etc.

(McCoy)
> But on my opinion it is worthwhile to think about it. Here in Central
> Vietnam the people plant Casuarinas (equisetifolia?) in the dunes. With
> all their symbiotic microorganisms they grow just excellent in the sand
> and produce a lot of litter covering the ground.

Yes, Casuarina's do well here. Definitely worth considering.

Reid, Aileen

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From: Reid, Aileen
To: MULCH-L@cornell.edu
Subject: More on organics
Date: Fri, 19 Jan 2001

This aspect of having the clay before the organic matter interests me. It is one of the principles underpinning a particular method of composting (whose name escapes me), but it requires all composts to have a 10% clay component in order to be able to form a clay humus crumb. Obviously well founded.

So I think we will work on the premise of getting some clay into the soil - sorry sand. :-) However sources of clay here are few and far between. We have bentonite which is quite alkaline and is not renowned for its high CEC and we have red mud - a residue from bauxite mining which is also highly alkaline and amended with gypsum, and also has higher than normal levels of radioactivity (thorium and radium-226) but has been evaluated as an amendment on vege crops and appears quite OK. However I am sure NASAA will not approve it as an allowable input under the organic certification scheme. Any other ideas? What about zeolites and other rock dusts - are they going to help in terms of giving organic matter something to hang off? Or maybe we should just move all our horticulture off the coastal plain!

Aileen Reid