Technologies

Sweet Potato Relay Cropping [Philippines]

Creation: 03/26/2016 10:23 a.m.
Update: 06/13/2019 2:24 p.m.
Compiler: Philippine Overview of Conservation Approaches and Technologies
Editor: –
Reviewers: Fabian Ottiger, Alexandra Gavilano

Lapat System

technologies_1301 - Philippines

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Completeness: 69%

1. General information

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

Key resource person(s)

SLM specialist:

Dinamling Djolly Ma

Department of Agriculture-Bureau of Soils and Water Management

Philippines

SLM specialist:

Raquid Jemar G.

Department of Agriculture-Bureau of Soils and Water Management

Philippines

SLM specialist:

Garcia Pastor

Visayas State University,

Philippines

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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

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

A farmer’s indigenous practice of growing sweet potato as a relay crop to its main crop of either rice or corn.

2.2 Detailed description of the Technology

Description:

It is the planting of sweet potato together with rice/corn on the same area, hence, maximizing the area for crop production. Specifically, a local sweet potato variety called “mayaman” is planted one to two months after planting rice/corn and is being cultivated in the field in between the rows of the above-mentioned main crop. The “mayaman” variety is selected by the farmers due to its excellent food quality and ability to produce more roots at its vine, enabling staggered harvesting and extending period of utilization. However, in some instances, rice and corn were planted at the same time.

Purpose of the Technology: The main purpose of using creeping type of sweet potato is to provide cover to the soil which addresses soil moisture conservation primarily during growing period and after main crop harvesting time. It also protects the soil against erosion. Moreover, it provides additional and alternative food source for the farmers, in case the main crop fails due to some reasons.

Establishment / maintenance activities and inputs: The main crop, either corn or rice, is planted first with a specified planting distance--75cm between rows and 75cm between hills with 2 to 3 seeds per hill (for corn) and 30cm between rows and 20cm between hills with 5 to 6 seeds per hill (for rice). After one month, the sweet potato cuttings are planted in between rows of the main crop at a distance of 1.5m between hills.

Natural / human environment: This relay cropping system is locally known as “lapat” in the areas of Matalom and Bato, Southern Leyte where it is commonly practiced.The soil in these areas is characterized as mostly acid soil. Whereas, its topography is generally comprises from rolling to steep hills. In terms of climate, rainfall is more or less evenly distributed throughout the year and typhoons usually occur during the months of October or November. In addition, most of local farmers cultivated 1 to 2 parcels with farm size from 0.12 to 5.95 hectares with farming as the principal source of livelihood and income. The fields ot the farms are basically rainfed because it is totally dependent on rainfall as water supply for irrigation.

2.3 Photos of the Technology

Media Gallery

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

Country:

Philippines

Region/ State/ Province:

Matalom, Southern Leyte

Specify the spread of the Technology:

evenly spread over an area

If precise area is not known, indicate approximate area covered:

< 0.1 km2 (10 ha)

Comments:

This is a traditional practice done by most of the farmers in the municipality of Matalom, Leyte.

2.6 Date of implementation

If precise year is not known, indicate approximate date:

more than 50 years ago (traditional)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

as part of a traditional system (> 50 years)

3. Classification of the SLM Technology

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

Cropland

Annual cropping

Annual cropping - Specify crops:

cereals - maize
root/tuber crops - sweet potatoes, yams, taro/cocoyam, other

rice

Number of growing seasons per year:

Comments:

Major food crop: Rice, corn
Others: Sweet potato

Major land use problems (compiler’s opinion): soil erosion, soil moisture

Major land use problems (land users’ perception): soil erosion

3.4 Water supply

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

rainfed

3.5 SLM group to which the Technology belongs

rotational systems (crop rotation, fallows, shifting cultivation)
improved ground/ vegetation cover

Intercropping

3.6 SLM measures comprising the Technology

agronomic measures

A1: Vegetation/ soil cover
A3: Soil surface treatment

Comments:

Main measures: agronomic measures

Type of agronomic measures: relay cropping

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

Wt: loss of topsoil/ surface erosion

physical soil deterioration

Pc: compaction

biological degradation

Bc: reduction of vegetation cover

water degradation

Ha: aridification

Comments:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion, Bc: reduction of vegetation cover

Secondary types of degradation addressed: Pc: compaction, Ha: aridification

Main causes of degradation: soil management (contouring is not practice in sloping areas), other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify (topography)

Secondary causes of degradation: crop management (annual, perennial, tree/shrub) (annual cropping), droughts

3.8 Prevention, reduction, or restoration of land degradation

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

reduce land degradation

Comments:

Main goals: mitigation / reduction of land degradation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

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Technical specifications (related to technical drawing):

Sweet potato and corn planted within an area

Location: Matalom. Leyte

Technical knowledge required for land users: moderate (proper planting distance and know how to mix crops)

Main technical functions: control of raindrop splash, improvement of ground cover

Secondary technical functions: improvement of topsoil structure (compaction), increase of infiltration, increase / maintain water stored in soil, increase of biomass (quantity)

Relay cropping
Material/ species: sweet potato
Remarks: 1.5m x 1.5m spacing in between the rows of main crop

Author:

Patricio A. Yambot, Bureau of Soils and Water and Management

4.2 General information regarding the calculation of inputs and costs

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

45.0

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
Plant material	Corn seeds	kg	2.0	0.78	1.56	100.0
Plant material	Rice seeds	kg	43.2	0.7777777	33.6	100.0
Plant material	Sweet potato	cuttings	13000.0	0.00555555	72.22	100.0
Total costs for establishment of the Technology					107.38
Total costs for establishment of the Technology in USD					2.39

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	clearing	March
2.	plowing	10 days after clearing
3.	harrowing	after plowing
4.	furrowing	after harrowing
5.	planting of rice	April
6.	planting of corn	2 weeks after planting rice
7.	planting of sweet potato	2 months after planting corn
8.	weeding	every month
9.	spraying	three times before harversting
10.	harvesting of rice and corn

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	Labour	ha	1.0	391.5	391.5	100.0
Total costs for maintenance of the Technology					391.5
Total costs for maintenance of the Technology in USD					8.7

5. Natural and human environment

5.1 Climate

Annual rainfall

< 250 mm
251-500 mm
501-750 mm
751-1,000 mm
1,001-1,500 mm
1,501-2,000 mm
2,001-3,000 mm
3,001-4,000 mm
> 4,000 mm

Agro-climatic zone

humid

Thermal climate class: tropics

5.2 Topography

Slopes on average:

flat (0-2%)
gentle (3-5%)
moderate (6-10%)
rolling (11-15%)
hilly (16-30%)
steep (31-60%)
very steep (>60%)

Landforms:

plateau/plains
ridges
mountain slopes
hill slopes
footslopes
valley floors

Altitudinal zone:

0-100 m a.s.l.
101-500 m a.s.l.
501-1,000 m a.s.l.
1,001-1,500 m a.s.l.
1,501-2,000 m a.s.l.
2,001-2,500 m a.s.l.
2,501-3,000 m a.s.l.
3,001-4,000 m a.s.l.
> 4,000 m a.s.l.

5.3 Soils

Soil depth on average:

very shallow (0-20 cm)
shallow (21-50 cm)
moderately deep (51-80 cm)
deep (81-120 cm)
very deep (> 120 cm)

Soil texture (topsoil):

medium (loamy, silty)

Topsoil organic matter:

medium (1-3%)

If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil fertility is medium
Soil drainage/infiltration is medium
Soil water storage is medium

5.4 Water availability and quality

Ground water table:

5-50 m

Availability of surface water:

medium

Water quality (untreated):

good drinking water

Comments and further specifications on water quality and quantity:

Seasonality of water quality: Spring

5.5 Biodiversity

Species diversity:

5.6 Characteristics of land users applying the Technology

Market orientation of production system:

subsistence (self-supply)

Off-farm income:

less than 10% of all income

Relative level of wealth:

average

Individuals or groups:

individual/ household

Level of mechanization:

manual work
animal traction

Gender:

women
men

Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly common / average land users
Population density: 200-500 persons/km2
Annual population growth: < 0.5%
Level of mechanization is manual labour or animal traction (carabao)
Market orientation: subsistence (food consumption of the family)

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

< 0.5 ha
0.5-1 ha
1-2 ha
2-5 ha
5-15 ha
15-50 ha
50-100 ha
100-500 ha
500-1,000 ha
1,000-10,000 ha
> 10,000 ha

Is this considered small-, medium- or large-scale (referring to local context)?

small-scale

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

mixed land ownership

Land use rights:

leased
individual

Water use rights:

open access (unorganized)

5.9 Access to services and infrastructure

health:

poor
moderate
good

education:

poor
moderate
good

technical assistance:

poor
moderate
good

employment (e.g. off-farm):

poor
moderate
good

markets:

poor
moderate
good

energy:

poor
moderate
good

roads and transport:

poor
moderate
good

drinking water and sanitation:

poor
moderate
good

financial services:

poor
moderate
good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Income and costs

farm income

decreased

increased

diversity of income sources

decreased

increased

workload

increased

decreased

Comments/ specify:

less weeding needed since sweet potato served also as cover crop

Socio-cultural impacts

food security/ self-sufficiency

reduced

improved

conflict mitigation

worsened

improved

Ecological impacts

Water cycle/ runoff

evaporation

increased

decreased

Soil

soil moisture

decreased

increased

soil cover

reduced

improved

soil loss

increased

decreased

soil organic matter/ below ground C

decreased

increased

Climate and disaster risk reduction

emission of carbon and greenhouse gases

increased

decreased

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

	Season	increase or decrease	How does the Technology cope with it?
annual temperature		increase	not well

Climate-related extremes (disasters)

Climatological disasters

	How does the Technology cope with it?
drought	well

6.4 Cost-benefit analysis

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

Short-term returns:

slightly positive

Long-term returns:

neutral/ balanced

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

Short-term returns:

slightly positive

Long-term returns:

neutral/ balanced

6.5 Adoption of the Technology

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

91-100%

Comments:

100% of land user families have adopted the Technology without any external material support

There is a little trend towards spontaneous adoption of the Technology

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Simplicity of the farming practice with minimal external input requirement How can they be sustained / enhanced? improvement in terms of planting distance or in the land preparation activity; look for other potential cover crop aside from sweet potato
Enhance Soil moisture conservation How can they be sustained / enhanced? conduct research study to have a more scientific basis
Additional food source and farm income How can they be sustained / enhanced? integration of other suitable crops for diversification; consider possible value-adding activity; help in the marketing of the product
Soil protection against erosion How can they be sustained / enhanced? Practice contouring and other soil conservation measures in the hilly land/sloping production areas to further minimize soil erosion

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

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
Low market price for sweet potato	Value adding through post-harvest processing of sweet potato;Livelihood development related to sweet potato post-harvest processing

7. References and links

Links and modules

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