| Saline
soil means soil which its salinity level is high enough
to be dangerous for economic crops.
How to observe
saline soil area in the Northeast
1. To find salty
dust among soil texture in summer or the land is left empty.
In rainy season, salty dust is melt and could not be seen.
2. To find weeds
like Namdang, Nampec, Namcom and Yakikrag.
3. In saline soil
area, rice does not grow. Its trunk is thin and its leaves
are pale. Some are died.
Area where
saline soil is found
There are
17.8 million rai of saline soil area in the Northeast. Moreover,
there are 19.4 million rai of area where it is easy for
the spread of soil salinity. Saline soil is found almost
every provinces in the Northeast.
Saline soil
area division
In the Northeast,
saline soil area can be divided into 4 types :
1. High-level
saline soil area is in the area where salty dust is found
among soil texture more than 10% of the area. Plant can
not be grown and the area is left empty.. It takes much
money for soil improvement.
2. Middle-level
saline soil is in the area where salty dust is found among
soil texture 1-10% of the area. Plant can be grow but crops
yield decreases.
3. Low-level saline
soil is in the area where salty dust is found among soil
texture less than 1% of the area. Subsurface flow is brackish
or brine and its depth is 2 m. from soil surface. Such area
is the paddy-field.
4. Area where
it is easy for the spread of soil salinity. Nowadays, such
area is the highland where crops are planted. Salty dust
is not found among soil texture but below the soil, there
is salty stone. When the rain falls, water from soil surface
flows pass salty stone layers and becomes salty water
flowing to the next plain area.
Management
of Middle-level and low-level saline soil for growing rice
Most saline soil
area in the Northeast is the paddy-field. Its soil texture
is sandy. There are water filled in the plain field 3-4
months. In rainy season, there is low soil fertility suitable
for growing rice. Because of saline soil, rice production
decreases (200-300 liters/rai) and such amount is not enough
for consuming in family. Land Development Department has
researched for an increase in rice production in low-level
saline soil area. The result is rice production which is
equivalent to 600-1,000 liters/rai. |
Steps
for an increase of rice production in saline soil area
1.
Fill some water (rain-water or irrigated water) in the field
in order to leach salt from the soil and drain it. Drain
water when it becomes pale brown. Soil salinity will decreases.
Do it 2-3 times before ploughing.
2. Add
organic matter like husk, animal manure or compost 2 ton/rai
in soil preparation period in order to make rice grows rapisly.
Green manure like the sesbania rostrata could be scattered
in the ratio of 7 kg./rai and incorporate it after 60 days
when it blooms. S.speciosa or S. aculeata could be use.
Soil amendments like slaked lime, marl could be used to
decrease acidity in soil. Add gypsum for the alkaline saline
soil like Kularonghai series which are dense. Its advantage
is to leach salt from the soil and make better water ventilation
in soil.
3. Make
levels of soil surface in the field smooth and be in the
same level. Its purpose is to fill water in all part of
the field and prevent salt accumulated in some area. Plough
the soil as deep as 30 cm.
4. Select
salt tolerant varieties of rice. Land Development Department
has researched and found varieties of rice suitable for
growing in the Northeast.
Native
varieties of rice : More-on, Kaotau, Koredeawbao, Dangnoi,
Jekkadod.
Suggested
varieties of rice : RD1, RD6, RD7, RD8, RD15, KDML105, Sanpatong,
Kaotahang, Kampai41, Kaopakmore148
5. When
the rice is small, it can not bear high-level salinity in
soil. So,select area where its salinity is middle. Select
salt tolerant seeds of rice 5 kg./rai.
6. Transplantation
the rice's age for transplantation should be 30-35 days
(maybe 45 days depending on rice varieties). An increase
in the rice's age will increase its ability for salt tolerance.
One of
the important factors for transplanting rice in saline soil
is the weather. The weather should be very hot and the shade
of light is in low level. Such weather is in the period
of rainfall before or after transplantation.
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