The ornamental farm is in the Puna district in a location in which all the jungle was removed by a D9 bulldozer. This is a common practice where where forests exist and fuel is available and affordable. It turns out that the farm has no soil or organic matter left, up to 15" of cinder on top of bluerock, root knot nematodes in a tightly planted long lived shrub crop, and bindweed (Convolvus arvensis)--one of the worst weeds in the world. Alright! Now, there is a challenge.
Over the years before I was called in, the farm transitioned from a chemical based system to a very low input Korean Natural Farming system for the health of the workers, consumers, and the land. Many of the plants were a deep green, surprising considering the lack of purchased fertilizers.. The Korean Natural Farming inputs are defintely doing a good job providing fertility. The owner was firm about not using synthetic herbicides, fertilizers or being reliant on outside organic matter to meet their needs.. The farm does not use the free "hilo dump mulch" since it is known to be one of the main transporters of fire ants. Perfect, this is my specialty.
Some of the site limitations were pretty easy to overcome--grow site adapted species to fill ecological niches that are not being exploited, utilize species that suppress or are resistant to M. javinica and M. cognita (root knot nematodes), and make support species the backbone of the system. The support species create organic matter to encourage beneficial soil life such as predatory nematodes and earthworms in addition to providing free fertility through nitrogen fixation and dynamic accumulation,. By cultivating and providing habitat for microbes we can unlock remaining fertility issues since the microbes are natures way of breaking down rocks/soil into plant available nutrients.
Now the bindweed is growing in a woody perennial crop, that is a challenge. I kept bindweed out of my orchard by preventitive weeding to elmiinate it but didn't have too much though. Communication with experts proved to be interesting. One distinquished expert encouraged using Roundup and 2,4,D--one of the main ingredients of Napalm., while communication with a local cultivator said that Roundup only encourages a bindweed explosion since the rest of the less noxiious weeds are killed.. I am awed by the power of strong herbicides, but it is not an option for my client or me. I feel that relying on inputs that cannot be produced locally create a system that is easily destabilized.
Chris Carter, the designer of the best permaculture sites I've seen, expressed exactly what I figured I would have to do--shade/mulch the bindweed out. Most weeds and plants slow down significantly when shaded and luckily bindweed is one of them. The solution is to plant site adapted species in an alley cropping/hedgerow system with vigorous pioneer species that provide ecological services such as shade, fertility, and improved nutrient cycling, A smoothering mulch will be created by chopping and dropping the pioneers after removing the bindweed.. The amount of required hand weed control remains the same until shade is created. Rapidly exapansive weeds always need a solid weed eradication plan.
I initially designed the system installation with no organic matter importation as requested--that is my specialty. But, a one time importation of organic matter would jumpstart the system incredibly. The weeds (except bindweed) would be smothered by the mlulch but more importantlly to me, the addition of woody mulch would encourage a fungally dominated soil that inhibits many weedy herbacious plants (thanks to soil scientist Elaine Ingram's research).
My semi-purist mind rationilizes that traditional cultures around the world have harvested the forest's wood, soil, humus, and mulch to jump start their culitivation systems. Even, in harsh deserts, permaculture systems are creating organic matter traps to collect organic matter blowing through. Today's economics and a dense jungle make it impossible for this farm to collect those inputs ,
The reality is that creating extremely rapid revenue from ground with no soil, bindweed, and rootknot nematodes would be, well, a miracle. I decieded to recommend a careful one importation of organic matter. The farm owner agreed. She has many employees to pay. We agreed that following published precautions and tactics to eliminate fireants would meet the farms' need to keep them out. I'll let you know how it all goes.
Agroforestry systems offer famers a break to sit back and watch the forest grow. Good things come to those who wait--after they establish their perennial polyculture system.. Over and over, I am finding that agroforestry can produce more for less in many places that agriculture struggles to exist, Intergrating agroforestry into existing farms, ranches, forestry systems, and habitat restoration projects can help land managers reach the next level of production, security, and ecological restoration.
NEW NOTE: 3/7/11--An experiment of sheet mulching the bindweed is looking very promising. We removed all the bindweed vegetation and laid cardboard between the Ti plants and on the path ways. Most vigourous weeds would come through the gaps quickly, a month later there is no sign of the bindweed. There are lots of small "pill bugs" which may be eaten the bindweed shoots, or it could be that the bindweed is being suffocated. I'll let you know if our luck continues.