Best plants for generating biomass:composting/mulching/improving soil fertility

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I have just had joined this forum, as I have been trawling the internet on the subject of improving the soil in mediterranean climates.  I was astonished how difficult it was to find information on this topic.

I found one research paper on Cardoon (CYNARA CARDUNCULUS L. AS A BIOMASS CROP FOR MEDITERRANEAN ENVIRONMENT: YIELDS AND APPLICATIONS). But apart from that the topic appears as deserted as our soil in August.

We are on the south coast of Crete, on quite a steep hill,  and have a piece of land most of which is unused. There are some olive and carob trees,  and for some weeks in the spring there is a green skin across the land,  but the rest of the time the soil is barren and compact.
The local green manures are Vetch and Field Beans, so I am currently giving them a try. And just talking to somebody a few minutes ago they have suggested Lupins, but they also said that when they tried them, they did not grow big at all.

I am looking at all kinds of ways of improving soil fertility - as a first step I'm enquiring what the best plants are for generating plant material / biomass. The second step then would be how to use it.

I found one thread on this forum on mulching which I have read in its entirety. Maybe I have missed other threads.  Any help much appreciated.
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on learning curve from 20 years UK gardening to
South-West coast of Crete; on South-facing slope, 250m, limestone on top of occasional clay and mainly rocks!;olive and carob trees and hopefully soon all kinds of fruit trees and herbs

David Bracey

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Michael, I think your choice is fairly limited to Leguminosae.  You could add alfalfa and I guess garden peas.  Clearly you need to get the crop in now with the autumn rains.  How do you cultivate your land, by hand, tractor, rotavator or with nothing. If you broadcast the seed...by hand could you lightly move it into he soil....are birds a problem?

If the locals use vetch and if you can buy the seed then this is an excellent place to start.
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

David Bracey

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A bit more, go the MGS website >Gardening information >Ask the Expert and halfway down is a question concerning green manures under citrus.  This will help.
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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MikeHardman

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Michael, welcome.

It can be difficult to adjust from UK-style gardening, I know.

Soil fertility is about nutrients, structure, fluids (both air and liquids), pH, antagonistic chemicals (eg. chromium), and the fungi and fauna that live in and on the soil. Depending on the size of plants, volume (effectively depth) of soil is also important.

One can analyse those, or one can be more practical and just see how things grow.
Wild plants grow well in the cooler months; witness the greening you mention. That suggests that the soil is already fertile - at that time of year.

You are probably wishing to grow plants just as well throughout the year. You could probably achieve that just by irrigating and choosing plants that would withstand the heat, sunlight and wind. But in discussion of mediterranean gardening there is often an undercurrent, as it were, of being water-wise. It could take a fair amount of water to irrigate as required, especially for a large area. And if plants did well, that demand could go up.

Perhaps you could consider what plants you would like to grow, and lean towards those that cope with mediterranean climates and ecosystems well. They often have lower fertility and water requirements. So your perceived need to fertilize could be less than you think.

...Just to suggest a way of looking at your problem.

Best of luck and enjoyment.
« Last Edit: November 16, 2012, 09:59:11 PM by MikeHardman »
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

Joanna Savage

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That sounds a wonderful project. Are you planning a garden for fruit and vegetables, or mainly ornamentals? Whichever you are growing be sure to read or listen to the writings of Oliver Rackham and Jennifer Moody first. There is a most interesting lecture by Rackham here, on the forum. It is under MGS Events and 'The Making of the European Landscape'. He doesn't give detailed instructions for making a garden,  but the ecology, history and archaeology , especially of Crete, which he describes is a fascinating background to what you are doing on your own plot.

Umbrian

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Yes, welcome to the Forum :)
You should also get a copy of "Making a Garden on a Greek Hillside" by Jacqueline Tyrwhitt - the author was the inspiration behind the forming of the MGS. By all means try to improve the structure of the soil so that your planting has an increased chance of success but as Mike said, lean towards subjects that are not only viable in your landscape but that will also enhance it and not change it too radically. Good luck :)
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.

Daisy

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Michael. I live on the north coast of Crete. I was lucky to have some topsoil here in my tiny garden when I moved in. However, there were also a number of mature trees with greedy roots, so it was lacking in nutrients.
I was much too impatient to grow green manures, so I used a lot of donkey manure.
It seems to have worked, as everything grows well.
I got the donkey manure from Alistair and Suzanne, who run a donkey sanctuary near Irapetra on the south coast of Crete.

http://walkwithdonkeys.com/

You might want to try both green and donkey manure.
These photos show parts of my garden after adding donkey manure.







Daisy :)








Amateur gardener, who has gardened in Surrey and Cornwall, England, but now has a tiny garden facing north west, near the coast in north east Crete. It is 300 meters above sea level. On a steep learning curve!!! Member of both MGS and RHS

David Bracey

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Daisy your secret is out, donkey manure!

I`m not sure if a green manure is the way to tackle "poor" soils since in my experience organic material  is photodecomposed within the same season. I think you have to decide what sort of mediterranean garden you are going to grow.  If you go back to basics the garrigue etc grows a marvellous assortment of beautiful plants.  Who could wish for anything more? There is plenty which will grow in your "poor" soils.  Look around.

There is among gardeners this desire to "improve" your garden, its plants and flowers.  What I would call the Northern Effect (ie Northern countries). 

As Mike says it is difficult to adjust from UK (North ) gardening.  It `s a matter of getting "your head around mediterranean conditions", the season, the heat and the lack of water. .  Its a steep learning.

 
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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MikeHardman

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Daisy - the word 'sumptuous' comes to mind!
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

pamela

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Hello Daisy
First of all your garden looks glorious!   Quite lovely indeed.  Every garden has its own charm and yours comes in on that score in leaps and bounds.
I was interested to read David's comment that organic matter decomposes in a year. Is it not worth adding manure or new soil to very deplete calciferous ground? If not what is the best solution ......
I do grow plenty of local plants which are happy here, several varieties of Thymes, Marjorams, lavenders, cistus etc amongst others but also I grow plants/trees/bulbs from other mediterranean climates i.e South Africa, Chile, California together with some sub-tropical species which seem to do well. When it comes to fertilizing I have never found out what is the best way to go. I am aware that my problem is the wide range of plants that I have. I dont think there is a 'one fits all solution', but if anyone knows differently!!!....I would be grateful.
Jávea, Costa Blanca, Spain
Min temp 5c max temp 38c  Rainfall 550 mm 

"Who passes by sees the leaves;
 Who asks, sees the roots."
     - Charcoal Seller, Madagascar

Umbrian

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Iam in complete agreement with you David on this subject  - it is a steep learning curve to get away from all the acquired knowledge and experience gained when leaving a temperate climate zone and starting from scratch in a Mediterranean one. Also I think one's very idea of what a garden should look like has to be adjusted to avoid considerable disappointment. If one's proposed "garden" is a previously untended hillside then to try to change it too drastically is a recipe for disaster in more ways than one. A successful garden always blends in with the surrounding countryside in my opinion and thereby can actually gain from it. The areas surrounding the house can be used for more "exotic" planting, things that need better soil, more care etc whilst the more distant areas should merge gently into the landscape with simpler planting that can survive in the prevailing conditions.
I think many of us start of full of enthusiasm and energy not always realising just what we are up against, the vagaries of the weather from one year to another, the difficulty in sourcing chosen plants readily, the many different pests and diseases that can wreak havoc (not to mention wild animals.) However it is a most enjoyable challenge despite all these things. :)
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.

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ritamax

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Calciferous soil, alkaline soil, soil with limestone means there is a lot of calcium, so there is the issue of possible chlorose on some plants, but most mediterranean plants are adapted to alkaline soils. There is of course big difference with poor, sandy, free-draining soil or poor, rocky, calcareous soil (grey-white) or a heavy clay soil (brownish) or the good Terra rossa type of soil (which is pH neutral). There are some acid soil types in the Mediterranean as well, where there is more rainfall. Tropical soils are mostly acidic, so tropical plants would need more feeding and tend to get chlorotic here. I tested the pH in my soil and the tap water, both about 7,5, quite typical for the region. Clay means there are minerals in the soil, so I would think there is no need for mineral fertilizing other than iron chelate or sulfur in a situation with chlorose. O.Filippi certainly advices not to fertilize mediterranean plants at all, for example grevilleas detest phosphor and don't need to be fertilized at all. To break up the compacted clay structure I have put perlite and cocos coir in, as the sand would have to be up to 50% to make a difference (I have done so only with succulents) and sand is heavy to carry around. Leaf mould would be good, as it does not have so much nutrients as compost or rotted manure. I mulch twice a year with compost alone (shrubs) or together with hoof and horn meal for extra nitrogen for flowering plants like Argyranthemum, Russelia, Lantana, Solanum rantonnetii, Strelitzia, Mandevilla, Pentas lanceolata, Hibiscuses. Heavy fertilizing increases soft growth and attracts aphids, mealybugs and co. and certainly every plant is better to be treated individually. I did make a list of my plants and looked up the requirements, and it came to a couple of groups, those needing well-draining, poor soil, those being happy in clay with occasional mulching, and those needing more humus (many subtropical and most tropical plants). Most plants seem to adapt to the given soil well.
Here is good information about sand and clay in the soil:
http://www.puyallup.wsu.edu/~linda%20chalker-scott/Horticultural%20Myths_files/Myths/Amendments%202.pdf
Hobbygardener (MGS member) with a rooftop garden in Basel and a garden on heavy clay with sand 600m from seaside in Costa Blanca South (precipitation 300mm), learning to garden waterwise

David Bracey

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What does Michael think?
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.