1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

No

2.1 Short description of the Technology

Definition of the Technology:

Acid soils are problematic, and the use of alkaline materials such as marl - agricultural lime that is excavated - helps to reduce the acidity and make the soil more productive.

2.2 Detailed description of the Technology

Description:

Adding marl to soils helps to manage acidity. Acidity is a problem in soil caused by iron sulphate that becomes sulfuric acid (H2SO4) upon oxidizing when exposed to the air. Therefore, it requires agricultural lime that are hydroxide, oxide compounds or carbonate with calcium or magnesium as the main component to neutralize or partly reduce the acidity. Agricultural lime is available mainly in the forms of slaked lime, marl, or ground limestone.
Acid sulfate soils are formed from the sediments of seawater or brackish water containing pyrite that changes to sulfuric acid upon oxidizing and accumulate in the soil. Acid sulfate soils are highly acidic, with low fertility. They are severely deficient in nutrients essential for plant growth such as phosphorus and nitrogen. Moreover, there are certain elements that are harmful to the plant growth such as iron, aluminium, manganese. Acid sulfate soils in Thailand occur along the East Coast, the West Coast and in the east part of the southern peninsula. Land Development Department reported that 35% of areas with acid sulfate soils are medium to severely acidic, limiting rice yields to between 625 and 1,560 kg/ha. When the Land Development Department started in 1963, it put the Acid Sulfate Soils Improvement as one of its prominent programs - and work still goes on up to now. The general practice has been to furnish farmers in the affected area with 1 ton of marl (CaCO3 deposit, excavated from the marl pit in Saraburi Province) per rai ( 6.25 rai = one ha). The objectives of using this technology are to (1) improve soils of acid property as soils are the basic resource for plant production, and (2) to increase the production of rice. Before applying marl, the land should be well levelled so that marl can react with acid soil efficiently. Tractors can enter and drop marl sacks over the paddy area, which is then spread by hand. The rate of marl to apply is around 6-12 tons/ha, depending on the soil pH.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

2.6 Date of implementation

If precise year is not known, indicate approximate date:

• 10-50 years ago

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through land users' innovation
• as part of a traditional system (> 50 years)

3.1 Main purpose(s) of the Technology

• improve production
• reduce, prevent, restore land degradation
• conserve ecosystem
• protect a watershed/ downstream areas – in combination with other Technologies
• create beneficial economic impact

3.2 Current land use type(s) where the Technology is applied

Land use mixed within the same land unit:

No

3.3 Has land use changed due to the implementation of the Technology?

Has land use changed due to the implementation of the Technology?

• Yes (Please fill out the questions below with regard to the land use before implementation of the Technology)

Land use mixed within the same land unit:

No

3.4 Water supply

Water supply for the land on which the Technology is applied:

• mixed rainfed-irrigated

3.5 SLM group to which the Technology belongs

• integrated soil fertility management

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• reduce land degradation
• restore/ rehabilitate severely degraded land

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology area

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

32.0

4.3 Establishment activities

	Activity	Timing (season)
1.	Soil analysis before the application of marl to know the rates of marl requirement	before land preparation
2.	Paddy should be adjusted or minimum tilled because marl can react with acid soil efficiently.	during land preparation
3.	Spreading the marl all over the plot.	during land preparation
4.	Pumping water into the plot up to 10 cm above the soil level. Keep the water until the soil becomes soft.	during land preparation
5.	Mixing the marl and wet soil and leave the mixture between 3-7 days.	during land preparation
6.	Applying the chemical fertilizer with the recommended rate	during land preparation
7.	Harvesting rice	harvest time

4.4 Costs and inputs needed for establishment

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Labor costs for spraying herbicides	baht per hectares	2.0	20.0	40.0	100.0
Equipment	pumping water	baht per time	1.0	100.0	100.0
Fertilizers and biocides	chemical fertilizer	baht per hectares	1.0	200.0	200.0	100.0
Fertilizers and biocides	herbicides	baht per hectares	1.0	59.0	59.0	100.0
Other	marl	dollars per hectare	1.0	36.0	36.0	100.0
Other	seeds	dollars per hectare	1.0	84.0	84.0	100.0
Total costs for establishment of the Technology					519.0
Total costs for establishment of the Technology in USD					16.22

If land user bore less than 100% of costs, indicate who covered the remaining costs:

-

Comments:

-

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	-	-

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	-	-

If land user bore less than 100% of costs, indicate who covered the remaining costs:

-

Comments:

-

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

herbicide price, marl price, and labour cost

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• not relevant

5.3 Soils

5.4 Water availability and quality

Is water salinity a problem?

No

Is flooding of the area occurring?

No

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

5.7 Average area of land used by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• state

Land use rights:

• communal (organized)

Water use rights:

• communal (organized)

Are land use rights based on a traditional legal system?

Yes

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Socio-cultural impacts

Ecological impacts

Soil

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

• > 50%

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?

• 91-100%

6.6 Adaptation

Has the Technology been modified recently to adapt to changing conditions?

Yes

If yes, indicate to which changing conditions it was adapted:

• changing markets

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Marl is an alkaline material, which can be used to solve the problem of the soil having acidity. The effect can last for several years. The cost of acid soil improvement by applying marl is low; farmers can invest in it.
Applying marl will increase more fertility to the soil, as there are nutrients with positive charges, namely calcium (Ca) and magnesium (Mg).
Applying marl will hasten the decomposition of organic matter in the soil and bring in more nitrogen in the form that plants can utilize better.

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Applying marl will hasten the decomposition of organic matter in the soil and bring in more nitrogen in the form that plants can utilize better.
Phosphorus still remains in the form useful to plants. As acidity is reduced, the solubility of toxic elements, namely aluminium (Al3+) and iron (Fe2+) is also reduced.
Lime has the property in making soil friable.

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
Too much application of marl will make the rice plant become yellow because rice does not like strong alkalinity.	Use liming materials following lime requirement from laboratory analysis

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
Too much application of marl will make the rice plant become yellow because rice does not like strong alkalinity.	Use liming materials following lime requirement from laboratory analysis

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

acid sulfate soil improvement

Available from where? Costs?

Land Development Department

7.3 Links to relevant online information

Title/ description:

acid sulfate soil improvement