Need help to find a tropical, drought tolerant, nitrogen fixing groundcover

Discussion in 'Put Your Questions to the Experts!' started by DineshSL, Jul 13, 2019.

  1. DineshSL

    DineshSL New Member

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    I need help to find a suitable ground cover. I have done a fair amount of research on the internet and can't seem to find one or a combination that will suit me.

    I live in Sri Lanka and my land is in a semi-arid area (around 1000 mm annual rainfall) and at approx. 1000 meters in elevation. The land is predominantly bare, sloping, eroded by wind and rainwater runoff that has exposed lots of small rocks. The soil is poor and compacted but otherwise has a decent clay / sand mix. For some perspective, even Glyricidia sepium struggles to grow here. There is wildlife including deer, rabbits, porcupine, monkeys, and wild boar that do significant agricultural damage in the area and also open grazed cattle. The climate is better described as mediteranean (hope I spelled that right) rather than tropical. At present, I can't afford to put fencing in but am planning to build a live fencing with Jatropha curcas in the short term and Maclura pomifera over the longer term. It is very complementary to say that my knowledge and experience in permaculture is limited:). I have started hand digging swales and the groundcover/s needs to go above and below them. I have tried planting crop and support species but most of them really struggle to grow and I am in desperate need of a browsing / grazing wildlife resistant groundcover for shading, moisture retention, and soil improvement.

    Ideally, the groundcover meets the following criteria:

    1. A creeping vine, not a climber
    2. nitrogen fixing
    3. drought tolerant
    4. not a forage plant, can be toxic
    5. fast growing, evergreen, self-seeding.
    6. height of 2-3 feet (plants grow to about half their normal size on my land so this should end up covering 12-18 inches).
    7. shade intolerant so that it will die off when a canopy is established.
    Would love to have some species recommendations that meet the above criteria or be as close as possible. I am also interested in any alternative solutions to my problem.

    Thank you very much,

    Dinesh
     
  2. K-I Permie

    K-I Permie New Member

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    Hi dinesh, where in Sri Lanka are you currently living?

    You are building swales, at this stage I’m assuming to reduce water runoff’s during heavy rain. Have you looked at building silt traps into the system to avoid erosion and retain soils to put back into your raised beds?

    the animals could possibly work to your advantage. Instead of trying to stop them until you are ready for fencing sow seed/ fodder crop (nitrogen fixing or mineral accumulating or both) into the swales. Not on your raised beds. When the animals forage they poop and presto you have manures to add to your raised edges.
    Again look at pioneer nitrogen fixing trees for the higher edges of the swales that you can Coppice (chop and drop) to begin building a soil profile and mulch. Maybe grow them out a little more before transplanting into the raised edges to avoid animal interaction.

    Cheers
    KI Permie
     
  3. DineshSL

    DineshSL New Member

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    Hi KI,

    Thank you for your response. I live in Colombo, but my land is in an area called "Welimada". The swales are to reduce run-off and erosion and also to increase groundwater levels. I've used an A frame to establish my contour line. The bottom of the swale is not entirely "level", leaving it with some high and low spots. That is easy to correct but I'm focusing on digging more swales rather than achieving a perfectly level swale bottom. The low spots are easily identifiable by the silt they accumulate - effectively an inbuilt silt trap. The silt provides a self-leveling element to the swale bottom. I'm also toying with the idea of planting vetiver grass on both sides of the swale.

    The issue I have with planting forage crops is that is that it creates problems with my nitrogen fixing shrub and tree species, and the fruit tree plants. See, the cattle have a rope around their necks, presumably for the owners to tie them down when needed. When they let the cattle loose, the rope drags on behind them. As the cattle move about, the young plants are either trampled or caught up in the trailing rope and broken. On top of that, they cause soil compaction. So they need to be kept off until I can control the grazing pressure on the land. I need the groundcover to increase soil moisture, fertility, and organic content in the top 12-24 inches of soil to enable the support and crop species to establish themselves. I made a big mistake in not mulching them last year when I planted (it's hard to cut and carry mulch on a slope and, quite frankly, I didn't realise the huge difference that the mulch can make to early establishment of the crop and support species. I've added the mulch this year and am now waiting for the rains. My thinking is that the groundcover is critical to support the mulch and accelerate soil improvement. The best groundcover that I've found so far is Mucuna bracteata. It's seems to be ideal for me with the only drawback being that it is also a climbing vine, which means I have to manually cut it off the crop and support species several times a year to prevent them getting smothered. Initially, this is manageable but will become impractical as the number of trees increase. I suppose my biggest problem is that I don't live on the land but only get to spend several days a month on the property. So I need a system that can be made to work with minimal human input.

    Best regards,

    Dinesh
     

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