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  • From: Meg Mullett <meg@kcnet.com>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Re: Cultivating saline land
  • Date: Fri, 14 Jan 2005 11:12:38 -0600

>Amrita wrote:
>Can anybody throw some light on what really are the options for these
>farmers? What are the saline lovig commercial crops that could sustain
>them in
>the meantime?

Hi Amrita,

First let me say that I am definately no expert on saline soils. I'm
just interested and have read a bit about it.

First off, I think the answer to your question is going to vary alot
depending on the region, the location of its water table, annual
rainfall, and drainability of the soil.

Some crops that are considered "highly salt tolerant" - there really are
no "saline loving" plants - are tall wheatgrass, puccinellia, bermuda
grass, barley, saltwater couch, and salt bush. However, these plants
can generally only tolerant saline concentrations of 2500-5000 ppm. The
average saline concentration of seawater is around 35,000 ppm, over 7
times the tolerant level.

according to http://www.cbmcc.vcn.com/saltsoil.htm
"
Saline soils cannot be reclaimed by any chemical amendment,
conditioner or fertilizer. Only leaching can remove salts from the
plant root zone. The amount of water necessary is related to the initial
salt level in the soil, the final salt level desired and the quality of
the irrigation water.

Six acre-inches per acre of good quality leaching water passing
through a foot of soil will reduce the salinity by about 50 percent.
One acre-foot per acre will reduce the salinity by about 80 percent, and
2 acre-feet per acre passing through 1 foot of soil will reduce the
salinity by about 90 percent."

A similar paper is here:
Managing Saline Soils:
http://www.ext.colostate.edu/pubs/crops/00503.html

Therefore, we can hope that these farmers could plow deep, add organic
matter, and then leach, which might leach a lot of the salt down below
the root zone. - Hopefully not leaching into the water table.

I don't know if these areas are subject to annual monsoons or heavy
rains. Do you?

Meg in KS

other interesting further reading:

China Experiments with sea water irrigation
http://english.people.com.cn/english/200012/22/eng20001222_58549.html

Interesting paper on irrigating crops with sea water helps explain some
of the difficulties
http://www.miracosta.edu/home/kmeldahl/articles/crops.pdf

-----------
Tsunami turns soil saline, fields uncultivable in Tamil Nadu

Like fishermen, farmers in tsunami-affected regions are also coming to
terms with their losses, as, besides washing away crops, the sea water
has turned their lands saline


Scores of farmers in Tamil Nadu face an uncertain future as the water
that engulfed their fields, washing away crops, has left the soil saline
and uncultivable. Although the extent of the damage is yet to be fully
assessed, officials say that a substantial proportion of cultivable land
has been contaminated by salt water.

Admitting that the tsunami would definitely impact agriculture, Dr R N
Adsule, a soil and agri-chemistry expert from Pune, explained that too
much salt in the soil prevents crops from taking in water and nutrients
by osmosis, causing them to perish.

The extent of damage caused by the tsunami has prompted the state’s
agriculture department to dispatch four mobile testing vans -- two to
Nagapattinam (one of the worst affected regions in Tamil Nadu) and one
each to Cuddalore and Kanyakumari -- to assess the extent of the
destruction caused to farmland.

These vans will test local soil and hand cards out to villagers stating
the level of nutrients in the soil. They will also suggest remedial
measures. It is being estimated that it will take two seasons for the
soil to return to its pre-tsunami composition and become arable again.

Meanwhile, the agriculture department is waiting for a detailed report
to come in to suggest methods to treat the soil, like leaching the soil
by adding gypsum, repeatedly treating it with fresh water, draining the
water and ploughing the soil.

“In addition to all this we suggest the farmers plant certain kinds of
plants that will grow, die, decompose and, in the process, enrich the
soil. Cultivation of paddy, which is the main crop grown here, will not
be possible now,” says Thiru P Baskaradoss, Tamil Nadu’s agriculture
secretary.

Although no funds have yet been allocated for soil treatment, the
agriculture secretary estimates the costs would amount to Rs 5,000-Rs
7,000 per hectare.

There is also some confusion about the extent of land damaged by the
salt. “Our rough estimate pegs the extent of salt water-contaminated
arable land at 75,000-1 lakh hectares, mainly in Nagapattinam,
Cuddalore, Kanyakumari and Kancheepuram districts,” says Baskaradoss.
However, Dr V Murugappan, director of the Centre for Soil and Crop
Management Studies at Tamil Nadu Agricultural University, says the
extent of affected area is much lower.

“We estimate about 5,500 hectares to be contaminated by sea water in the
Nagapattinam, Kivalur, Tirukuvalai, Maladudurai, Sirkali, Tharangampadi
areas. This works out to 4,000-odd hectares under paddy, 1,500 under
groundnut and 100 hectares under pulses. Paddy now hasn’t reached the
harvesting stage, but the plant surfaces are coated with mud from the
floods. Coupled with the high salt content this is bad news,” says
Murugappan.

Over 2,500 farmers in Karaikal, Pondicherry, lost years of hard work to
the salty, muddy water that engulfed their fields. According to experts,
the damage to soil in the Cauvery delta is so severe that it will not
yield anything for the next two to three years.

Source: The Indian Express, January 7, 2005
www.ndtv.com, January 7, 2005




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