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Monday, July 11, 2016

Fruits for a harsh coastal habitat

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 NiƱa 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 

Date palm
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 

Saba banana 
Dragonfruit/ Pitaya 
Henna (Lawsonia inermis)
Indian Jujube
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

Saba nut

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



Lobi Lobi


Strawberry guava 

Jelly Palm



Spanish lime 

Kei Apple 

Mammey sapote 


Singapore (muntingia calabura)
Sea grape (Coccoloba uvifera)

These help greatly to narrow down the early wins. And we have proceeded to source and acquire many of these from collectors in Indonesia, by propagating ourselves or importing seeds

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 

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