Agri Kit Q&A - Salts removal at tsunami-affected regions (Japan)
The 2011 Tofuko earthquake and tsunami affected lots of Japan east coastal regions.
Salt (sodium chloride) from seawater and other chemical salts are deposited in soil.
It is better to reduce the amounts of salts in soil before starting something new.
High level of salts can progresssively increase the corrosion of new construction foundation.
High level of salts can inhibit new plants growing.
Some places, minor amount of radioactive materials could remain in soil. Although the amount is very minor and do not have immediate danger,
but the accumulation through period of time may have some effects that so far scientists can not determine it.
Experts agree that proper leach process is necessary to do salts reduction before rebuilding something or planting new crops.
If fresh water is used, the amount of water used in leaching process would be huge due to large amount of salts depsoisted in soil.
Since sodium ion (Na+) is easy to dissolve in water,
the remained chloride ion (Cl-) will mix with calcium ion to bound soil together.
It performs like a poor-quality cement, and salt hidden in bound up soil still remains there.
Agri Kit generates ionized water, so less amount of fresh water is needed in leaching process.
This makes leaching process more effective, and achieves better performance in salt reduction.
This point is important. Because at tsunami-affected region, the total amount of fresh water is limited.
Field Preparation
Small field
Setup water channel around the perimeter, and dig several holes in the field.
The distance between holes is about 10 ft (3 m).
At downstream, construct a pit for leached water collection. (Right first drawing)
Large field
Setup water channel around the perimeter, and dig out several channels in the field.
This distance better ditched channels is about 10 ft (3 m).
At down stream, construct a pit for leached water collection. (Right second drawing)
Leach Process
Spray ionized water from upstream to make soil wet, and fill water in holes one-by-one.
The ionized water can reduce soil static charge and loosen bound up soil, so more salts in soil can be leached out.
Repeat the leach process several times to progressively reduce salt contents in soil.
Salinity Evaluation
Depending upon the soil composition, the amount of salts in soil, and the amount of water used in field,
this process needs to perform several times in order to leach out most of salts in top soil.
Seawater has salinity of roughly 35,000 ppm (35 g/L). Fresh water has salinity of less than 1,000 ppm.
After performing several times of leach process, take statistical samples around the field, and use EC meter to measure salinity.
The field, if it is going to be used for vegetables or rice, the salinity level should be less than 600 ppm.
The hand-held EC meter can provide the reading within seconds.
If there is no EC meter available, make a small cup of water from statistical sample, and evaporate water out of content.
The remained solids, if there is no visible crystalized salt on paper, then it probably would be OKay.
The process looks simple, but it can save lots of work in the future. If soil has high salt content, particularly sodium, it will affect plant's ability to absorb Mg (Magnesium).
This will cause plant weaker in its structure and other consequence.
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