Permaculture, Intercropping, Agroforestry, and Agroecology. Page 2
Here are some design ideas, taken from nature, and integrating wildland plants, for creating a more stable garden/orchard using the concepts from permaculture, agroforestry, ecosystems agroecology, in California.
First, using the principles from ecology, look to nature to see how to arrange plants and what plants to utilize. In nature, plants arrange themselves in certain ways. Water is usually at the lowest point in the area, and the plants that grow near the water, called wetland plants, have certain characteristics. On the edge of the wetland, certain other types of plants grow. Then, as the land rises above the wetland area, and the land becomes drier, away from the water, other drought tolerant plants naturally grow. Scientists have given names to each of these habitats, and the plants that inhabit them; riverine aquatic/riparian/wetland, lower alluvial zone, higher alluvial zone, riverbank, and upland/oak woodland/chaparral/coastal sage scrub. Mimicking and including nature in this way, and placing certain plant types and their natural companions in each area, makes your planting work better and more harmoniously. In a study of hundreds of intercropping experiments, a researcher in British Columbia proved that yields are increased when different plants are grown together than when each plant is grown alone in a pure stand. Try to move your planting as close to a natural state as possible, while incorporating your crop plants, using principles from ecosystems agroecology. Try to integrate your garden/crop area with indigenous plants. To create a ' plant community', you need a minimum of 5 different compatible plant species.
In the following pages are descriptions of the different ways plants are arranged in habitats in the wild, and the general characteristics of each area. You can use this to your advantage as a guideline when planting. In earlier times, rivers flooded, and lots of rich sediment was deposited here and there on the land, so there is not a clear-cut delineation between some of these habitats. But you can kind of get the idea about which kinds of habitats support which kinds of plants. In a garden, plants are placed in rows, for ease of cultivation, harvesting, etc. If you have an area that you can deal with easily, you can free-form the different areas, and have no exclusively straight or contour lines, but it is much harder to weed, water, cultivate, harvest, etc.
Wetland (#1 in river photo)- A wetland is an area that is wet all the time, where water is standing or running, full time, a creek, a river, or a pond. Examples of some plants that reside here naturally are rushes (Juncus spp.), sedges (Carex spp.), cattails (Typha spp.), bulrushes (Scirpus spp.), and pond lily (Nuphar luteum ssp. polysepalum). Here the soil is constantly wet, there are low levels of oxygen in the soil, and high levels of water, and the plants can vary between mycorrhizal and non-mycorrhizal. Usually these plants are inhibited by mulch. This area would be best closest to the house.
(#2 in river photo) Lower Alluvial Area- Just above the wetland area where, historically, the soil was highly disturbed from regular flood waters (though hardly ever seen now, as most rivers are dammed so they cannot flood) is the lower alluvial area - This area is above the water line, the soil is highly disturbed, moist, and fertile- this is the area where the sediment deposits landed when the river would flood about every year (before dams existed). Then, after the flood waters receded, people would plant their seeds, in the fertile, disturbed, moist soil. The plants growing here are ruderal, short-lived, opportunistic, and need moist, disturbed, fertile soil to grow well. Because the habitat has everything plants need, the plants growing here are usually non-mycorrhizal, and are more competitive and less cooperative (the weeds of the world). Because there is enough water, enough oxygen in the soil and enough fertility, plants don't have to rely on each other as much. Soil should be tilled every year; incorporate compost and/or animal manures into the soil when you till, and no mulch should be placed on top of the ground, as a rule. No-till is just another word for very lightly tilling (no deeper than 1/2 inch). Also, burning plant debris = soil disturbance (= shallow tilling).
An example of lower alluvial area crops are many annual non-mycorrhizal garden vegetables, that do not tolerate mulch very well, and many common short-lived garden plants; examples being kale (Brassica oleracea, B. napus), pak choy (Brassica rapa ssp. chinensis), flat-leaf parsley (Petroselinum neapolitanum), and carrot (Daucus carota ssp. sativus). Weeds can be pulled any time of year, in this zone. Try to pull them before they drop their seed, to reduce the seed bank so you have less to pull next year.
(#3 in river photo) Upper Alluvial Area-Just above the lower alluvial area is the upper alluvial area . Historically, this zone floods every few years or so, is a drier area, farther from the water, where the plants do more sharing of nutrients and water, with their companion species. The best plants for this area are, annual mycorrhizal garden plants, such as corn (Zea mays ssp. mays) , squash (Cucurbita spp.), potatoes, peas (Pisum sativum), beans (Phaseolus vulgaris), grains, etc. Usually these plants can tolerate and seem to do ok with thin straw/compost mulch.
Many of the plants are more long-lived, like perennial, mycorrhizal, usually deciduous shrubs and trees. These are called bridge plants because they connect/bridge the dry upland and wetter lowland areas. This is the orchard habitat.
Examples are apples, pears, plums, peaches (Prunus persica), almonds (Prunus dulcis), Hawthorn (Crataegus spp.), Service Berry (Amelanchier spp.), dogwood (Cornus spp.), ash (Fraxinus spp.), elderberry (Sambucus spp.), willow (Salix spp.) alder (Alnus spp.), cottonwood (Populus spp.) A layer of compost mulch is great here, and/or use live understory herbaceous companion plants, to cover the ground. For weed control, pull the weeds just during the winter and spring; during the summer and fall, either smother the weeds with mulch or cut them off below ground level, then cover with mulch.
(#5 in river photo) Upland/Wild Area- This zone is the driest area, farthest from creek, composed of longer-lived perennials, shrubs, trees, many evergreen, with most plants being highly/obligately mycorrhizal (mycorrhizae- a fungal companion of many plants that connects roots of neighboring plants together via the long strands of its body, or mycelium). The soil here is drier, with highest oxygen levels, and the plants are under the most drought stress in the dry season, being highly adapted to share nutrients and water with their companion species. Upland plants survive by sharing.
In this zone,which does not flood, you do not want to till, and you definitely need mulch, to support the soil microflora and microfauna, and the associated trees and shrubs, and perennials. During the winter and spring, if you pull up weeds, mycelial strands are broken, but since they are actively growing now, they can regrow and reconnect plants. During the summer and fall, mycorrhizae go dormant. If you pull weeds then, and break the mycelium, the fungi cannot regrow and reconnect, and neighboring plants, can wilt and die quickly. The mycorrhizal strands are like lifelines for plants. Mycorrhizal strands enable plants to receive basic food, water, and protection from diseases. These effects are not seen as much in wet years, but are seen more often in drought years, when plants are under severe drought stress. Examples are very long-lived plants, slower-growing, which provide long-term stability to the environment, such as evergreen oaks (Quercus agrifolia, Q. berberidifolia), manzanitas (Arctostaphylos species), and Pines (Pinus species). This area would be best located farthest from the house.
These long-lived plants are interplanted with the shorter-lived , pioneer, nitrogen-fixing California lilacs (Ceanothus spp.), shrubs which help the later successional species to become established, by providing shade, nitrogen, water, and other nutrients. In this zone, since the plants rely heavily on mycorrhizae for their survival, and the strands of mycelium are interspersed throughout the soil, you don't want to break these strands that connect the companion plants to each other, by tilling, hoeing, or otherwise disturbing the ground.
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