Monday, July 11, 2016
Cowpea (left) and Lima bean (right) purchased in Ubud. Most likely imported product but well worth a trial. The Lima beans are probably the dwarf bush type
Growing in sodic and saline soils is difficult but not impossible.
It's always been an interest of mine to try and develop agroecologies best suited to the prevailing conditions, that provide sufficient nutrition for people, and then to see what kind of cuisine comes from this mix.
This is a different approach to the usual attempt to modify or shelter the foods we are accustomed to eating from the conditions of the site.
Of course I still do modify the site with inputs and soil conditioning and water harvesting, however it should be the path of least resistance leading to greatest yield and choice.
Life wasn't actually meant to be that difficult.
To that end I'm seeking beans and pulses that can grow in this hot semi arid alkaline, sodic and saline environment.
These preconditions exclude Peas, chickpeas and common beans, they just don't cope with heat and salt.
So far the review of published literature has led to the following candidates. The list is not exhaustive and it is in fact highly selective. If I already know I don't like the taste then it's out
Cowpea and Long bean (Vigna unguiculata and Vigna unguiculata sesquipedalis)
Moderately salt tolerant
These are the same species and exist in various intergrades. The long bean is usually a vining plant with soft green pods up to 0.5 m long eaten as a vegetable. The cowpea is usually a bush with fast maturing shorter pods that produce a dry bean.
However we have seed types that are inbetween, vining plants producing a dry bean
Both foods are delicious. Refried "black eyed peas" are delicious
The leaves are eaten as a traditional vegetable in Africa and are nutritious
Kacang Bogor / Bambara groundnut / Mugo bean ( Voandezzia subterranea)
Lima or Butter bean (Phasoleus lunatus)
Moderately salt tolerant
Pigeon Pea / Kacang Undis / Kacang Lebui ( Cajanus Cajanus)
Turi / Kentujur ( Sesbania grandiflora)
Winged bean ( Psophocarphus tetragonolobus)
Functions of legumes in this Agroecology
Pulses, beans and legumes are a good source of dietary protein and for much of the worlds population they are an essential dietary component. Cereal + bean/pulse is the basic dietary formula.
However we are not those people. The setting here is adjacent to the coast which is rich in protein sources, and on land we can maintain herds of beasts and poultry for our protein needs.
There is instead a shortage of dietary fibre and carbohydrate, and of fruits and vegetables, in this and similar Island habitats
So the purpose of legumes in our design is different and focused on the additional benefits of legumes.
We only select the plants we like to eat, or those with potential to be processed into something we enjoy. I love Felafel and because neither chickpea or fava bean suit this climate or soil, then we will adapt using the tolerant Lima bean
B) Dietary fibre
The fibre content of beans and pulses is important for gut health. It's long been known that the physical bulk is important for movement through the digestive tract, and more recently it's known that fibres of these foods are especially effective at enabling excretion of excess cholesterol from the body. What's most recently under consideration is the reassessment of fibre not just as bulk, but also as a substrate for the growth of our gut micro flora which has direct impacts on brain health and all other aspects of our wellbeing.
C) Soil carbon and fertility
For each 1 Kilogram of Nitrogen fixed from the atmosphere by the symbiotic bacteria living in association with the roots of these plants, a further 10 Kilograms of Atmospheric carbon can be captured and stored as biomass.
The main limitation for our soils is water and nitrogen. Water is provided by increasing the water holding capacity of the soil through elevating soil organic matter. This acts as a sponge, and also to reduce the bulk density of the sodic topsoil. The increased porosity assists rainwater infiltration into the subsoils.
More fertility and effective rainfall = more shade, fruit and comfort
D) forage and mulch
I'd rather an egg, cheese or meat over beans anyday.
And despite much internet propaganda promoting animal products as unhealthy and unsustainable, the truth regarding forage and pasture fed animals is just the opposite.
Sheep, geese, chickens, quail, fish and maybe a cow, we do intend to raise multiple types ofvanimalschere and so we need ample forage resources.
We also need bedding to soak up manures and ensure keeping animals remains a synergistic process that builds soils and gardens
The conditions in Sumbawa are extremely harsh however in almost any environment there are some things that can grow
The specific limitations on this site areas follows
Rainfall arrives in a slightly bimodal pattern often with light falls in October, a dry November with a peak in January and February. In La Niña years it can extend till may however falls from march onwards are erratic
The total rainfall is in the order of 1250mm per year
The effective rainfall is very low because of its infrequency. The peninsular is in a partial rain shadow, with falls often visible just 2km away. The effect of nearby hills and the effect of the 4000m plus mount Rinjani to the west leave this North West corner of Sumbawa quite dry compared to the west coast several kilometres further south. When light precipitation falls on the dry soil, in combination with the heat and winds, most or all evaporates without being available to plants.
Exacerbating this problem is the accumulation of salt. The soils are quite salty and this makes much moisture unavailable to the vegetation, much like a shipwreck victim at sea who dies of thirst at Sea, Surrounded by water.
The soils themselves are a sand loam topsoil of about 20-40cm over a white coral sand. While the topsoil has some nutrients, it's structure is very poor being both fine and dense. This causes it to drain and infiltrate water poorly, and once wet the moisture doesn't drain into the subsoil as the finer material causes it to act as a perched water table.
The subsoils are very infertile and hostile to plant roots. They are a pure sand mixed with some large chunks of coral. They are salty and relatively dry because the rainfall doesn't infiltrate well through the topsoil
All soils on the site are low in major plant Macronutrients, Nitrogen and Phosphorus with shortages in all others except calcium.
Its the worst I've ever had to contend with without a doubt and as I've discovered the limitations, particularly below the surface, I've greatly down sized my expectations of what can be done on this site
However, it's worth trying some things just to push the envelope, and because, it's all I have.
My first course of action was to survey the local area and areas where the conditions are similar to see what can grow.
Over in the village where people have erected fences to protect from goats there are some interesting finds
A local citrus which resembles a kind of Lemon, and is known as Lemon Tea, but is not the lemon that is imported
Also visible in this picture are Sapodilla and Papaya
Additionally I surveyed similar areas both sides of the Alas straits and identified further species with potential
Henna (Lawsonia inermis)
Prickly pear (opuntia species)
My third course of action was a review of the literature on tolerances to salinity and sodicity by common crops and trees. This confirmed the previous findings and suggested more
This is really a very drought and salt hardy crop.
Under stress of drought and/or salinity the pineapple switches it's metabolism to CAM cycle and acts like a Cactus in its water use and metabolism
Singapore (muntingia calabura)
Sea grape (Coccoloba uvifera)
My intention here is a full and living Agroecology that will work in unison to create a fertile and comfortable living space. It should combine many species and compatible systems
This is easily the most extreme conditions I have ever had to establish a human habitat.
Saline and sodic, with a 4 month rainy season, sand infertile soil only 20cm deep over coral sands
The following post looks at some of the methods we are using to create a positive change on this barren site
Absolutely the most important first step on this exposed plain. The livestock and the wind conspire to make this an inhospitable place for trees to establish
The winds damage plants directly, and indirectly by greatly increasing their water consumption.
F) pit gardens