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

When were the data compiled (in the field)?

20/01/2009

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

Yes

2.1 Short description of the Technology

Definition of the Technology:

A Terrace is a structural SLM practice with a raised flat platform built on the slope to reduce soil loss and runoff on the slope, increase the rainfall infiltration and yield.

2.2 Detailed description of the Technology

Description:

A terrace is a leveled section of a hilly cultivated area, designed as a method of soil conservation to slow or prevent the rapid surface runoff and erosion of topsoil. Often such land is formed into multiple terraces, giving a stepped appearance.

Purpose of the Technology: To change the landform for better agricultural condition of operation of tillage and harvasting, reduction of soil erosion and water loss and finally for higher production.

Establishment / maintenance activities and inputs: The building of a terrace in the loess plateau takes long because loess is very soft and deep and the severe soil erosion and shortage of water in agriculture hinders the process, as well. Previously, terraces were constructed by hand. These terraces weres narrow and damaged by the great storms. Now, the machinery is used to build wide terrace with high bank size in the loess plateau. The establishment of terrace needs a lot of money but it is a long-term investment. The maintenance of terrace is considerable economic because the major efforts are the annually improvment of terrace bunds .

Natural / human environment: The soil erosion is very severe because of the cohesionless loess soil and very intensive rainfall storms in the summer and autumn that would destroy the land surface into broken hilly area. Terrace is a kind of measure to resolve it combining with crops. The human activities here is very intensive because they must plant on the slopes that would make the soil erosion greater.

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:

• 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)

Comments (type of project, etc.):

The terrace in this site has been formed since 1994 with machinery. The land is quite wide and large enough for agriculture in the hilly loess region,

3.1 Main purpose(s) of the Technology

• reduce, prevent, restore land degradation

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

Comments:

Major land use problems (compiler’s opinion): Soil and water losses are alarming in this region. The loose loess, steep slopes, and intensive storms in the summer and autumn, accelerates this process. Aditionally, the lack of rainfall negatively impacts agriculture and vegatation. Sediment deposition could increase the river bed and diminish capacity of reservoirs. On one hand side floods occur frequently because of fast and large runoff and on other hand side sedimentation in rivers reduce their water carring capacity.

Major land use problems (land users’ perception): The low yield of crops and the low income from land is more important for the local people. It is necessary to improve the agricultural conditions. The land, especially the tableland and gentle slope land could be convert into terrace.

Future (final) land use (after implementation of SLM Technology): Cropland: Ca: Annual cropping

Type of cropping system and major crops comments: The composation of agriculture is very simple here.

Livestock is grazing on crop residues

If land use has changed due to the implementation of the Technology, indicate land use before implementation of the Technology:

Grazing land: Gi: Intensive grazing/ fodder production

3.3 Further information about land use

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

• rainfed

Number of growing seasons per year:

• 1

Specify:

Longest growing period in days: 300Longest growing period from month to month: March to NovemberSecond longest growing period in days: 200Second longest growing period from month to month: April to October

3.4 SLM group to which the Technology belongs

• cross-slope measure

3.5 Spread of the Technology

Comments:

Total area covered by the SLM Technology is 253.3 m2.

The total area with different measures is till to 2000. Yanhe River is a first class branch of Yellow River, China. The average channel slope is 3.26‰, and the area of whole basin is 7,687 km2. It is in the semi-arid North Temperate Zone with an average annual precipitation varying from 500 to 550 mm, and an average annual air temperature ranging from 8.5 to 11.4℃. It is in hilly gully area of the Loess Plateau covered by loess. The landform is seriously broken by cutting gullies induced by water erosion. The gully density (the length of channel in one km2) is amount to 2.1 to 4.6 km•km-2. The soil loss is severe all along.
The Ganguyi Hydrology Station (109°48′E, 36°42′N) located in the Ganguyi Town, Baota Country, Yan’an City, Shaanxi Province. The area up Ganguyi Hydrology Station is 5,891 km2, including of Jingbian County(256km2), Zhidan County(708km2), Ansai County(2,699km2) and Baota County(2,228km2). The average annual runoff is 0.22 billion m3, and the runoff modulus accounting for 4,776.36 m3•km-2•yr-1. The average annual sediment flow is 4.776

3.6 SLM measures comprising the Technology

Comments:

Main measures: structural measures

Secondary measures: vegetative measures, management measures

Type of vegetative measures: aligned: -along boundary

3.7 Main types of land degradation addressed by the Technology

Comments:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion

Secondary types of degradation addressed: Hs: change in quantity of surface water, Hw: reduction of the buffering capacity of wetland areas

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (The natural vegetation in this region is grass on theslope and trees on the gully and alluvial land. After the destroy of natural, the soil loss increases greatly.), Heavy / extreme rainfall (intensity/amounts) (About 70% of annual rainfall is in the summer and autumn. The storm is very intensive.), population pressure (The population density account for 71 capita per square km.)

Secondary causes of degradation: droughts (The rainfall varies greatly in different year and different seasons. The drought happened frenquently.)

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

4.1 Technical drawing of the Technology

4.2 Technical specifications/ explanations of technical drawing

The brief structure of terrace in the Yanhe River Basin.

Location: Zhifanggou Watershed. Ansai County, Shaanxi, China

Date: 2008-12-15

Technical knowledge required for field staff / advisors: low (The location selection and how to build a good terrace need special knowledge on soil engineering.)

Technical knowledge required for land users: moderate (It is easy to know the benefit for all the local farmers.)

Main technical functions: control of concentrated runoff: retain / trap, reduction of slope angle, increase of infiltration

Secondary technical functions: increase / maintain water stored in soil, improvement of water quality, buffering / filtering water, increase of biomass (quantity)

Aligned: -along boundary
Vegetative material: G : grass
Number of plants per (ha): 50000
Vertical interval between rows / strips / blocks (m): 2.5
Spacing between rows / strips / blocks (m): 0.5

Grass species: Natural grass to protect the bank of terrace.

Slope (which determines the spacing indicated above): 20.00%

If the original slope has changed as a result of the Technology, the slope today is (see figure below): 2.00%

Gradient along the rows / strips: 1.00%

Terrace: bench level
Vertical interval between structures (m): 2.5
Spacing between structures (m): 8
Height of bunds/banks/others (m): 2.5
Width of bunds/banks/others (m): 8
Length of bunds/banks/others (m): 50-100

Construction material (earth): The terrace in the Loess Plateau are used local soil/earth directly.

Slope (which determines the spacing indicated above): 30%

If the original slope has changed as a result of the Technology, the slope today is: 30-60%

Lateral gradient along the structure: 2%

Vegetation is used for stabilisation of structures.

Change of land use type: Wild grassland or range land before mostly. Some time the cropland on the slope.

Change of land use practices / intensity level: The labor is less intensive on the plain platform.

4.3 General information regarding the calculation of inputs and costs

Specify currency used for cost calculations:

• US Dollars

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:

0.83

4.4 Establishment activities

	Activity	Type of measure	Timing
1.	Survey and design	Management	Before construction
2.	Move the topsoil to other place	Management	1st step of construction
3.	Built the platform and bank with soil digged	Management	2nd step of construction
4.	Backcover the topsoil on the surface of platform	Management	3rd step of construction
5.	Check and accept the terrace	Management	After the terrace finished

4.5 Costs and inputs needed for establishment

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Survey and design	Person/day	45.0	8.8	396.0	100.0
Labour	Building terraces (machine price included)	Person/day	75.0	19.0	1425.0	100.0
Total costs for establishment of the Technology					1821.0

Comments:

Duration of establishment phase: 0.5 month(s)

4.6 Maintenance/ recurrent activities

	Activity	Type of measure	Timing/ frequency
1.	Reinforce the bank	Structural	annually
2.	Fill the erosion hole of the landform	Structural	annually
3.	Build the edge in some terraces	Structural	annually
4.	Reinforce the bank	Management	annually
5.	Fill the erosion hole of the landform	Management	annually
6.	Build the edge in some terraces	Management	annually

4.7 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	Keep Terraces in shape	Person/day	30.0	8.8	264.0	100.0
Total costs for maintenance of the Technology					264.0

Comments:

Machinery/ tools: Crawl dozer and small traditional hand tool., crawler tractor, spade

In general condition, slope and soil, in the middle reaches of Yan River Basin. The prices of labour-day and Machine-hour are around 2005.

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The terrace on the steep slope need more input for more soil and earth should be moved. It is the most important factor.The soil depth is not so important for the deep soil layer here.The cost of labour increases greatly in the last several years and the cost of construction of terrace increased.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• convex situations

Comments and further specifications on topography:

Landforms also: mountain slopes and hill slopes

Slopes on average also very steep

5.3 Soils

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 texture: There are more than 50% soil particle are fine sand with size between 0.05 and 0.1 mm.

Soil fertility very low: Lack of N, P and SOM.

Topsoil organic matter: The average Top-SOM of cropland is about 0.05%

Soil drainage / infiltration good: The inflitration of Loess is very fast, but it is prone to sealing when flashing.

Soil water storage capacity low: It is easy to evaporation and drainage.

5.4 Water availability and quality

Comments and further specifications on water quality and quantity:

Availability of surface water medium: It is very stable in this region.

Availability of surface water also poor/none: Nearly all the branches of Yanhe are seasonal river.

Ground water table: It depends on the landform. In valley and alluvial land, it is shallow.

Water quality: Good quality for there are few pollution sources.

5.5 Biodiversity

Comments and further specifications on biodiversity:

It is very stable in this region.

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly common / average land users

Difference in the involvement of women and men: No clear difference.

Population density: 50-100 persons/km2

Annual population growth: < 0.5%

80% of the land users are average wealthy (The terrace are build together in some villages for all the people funded by national subsidy.).

Off-farm income specification: The yield of terrace is much high and stable.

Level of mechanization manual work: The harvesting and other management are by hand, even the tillage on the nerrow terrace

Level of mechanization animal traction: Tillage with animal power mostly in the wider terrace.

Market orientation mixed subsistence/ commercial: Some production for themselves, but most of production is exchanged on the market.

5.7 Average area of land owned or leased by land users applying the Technology

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

Land ownership:

• state
• communal/ village

Land use rights:

• individual

Water use rights:

• open access (unorganized)

Comments:

Like other rural area in China.

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Water availability and quality

Income and costs

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Soil

Biodiversity: vegetation, animals

Other ecological impacts

6.2 Off-site impacts the Technology has shown

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

Gradual climate change

	Season	Type of climatic change/ extreme	How does the Technology cope with it?
annual temperature		increase	well

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local rainstorm	not well
local windstorm	well

Climatological disasters

	How does the Technology cope with it?
drought	not known

Hydrological disasters

	How does the Technology cope with it?
general (river) flood	well

Other climate-related consequences

Other climate-related consequences

	How does the Technology cope with it?
reduced growing period	not known

Comments:

Loess is very prone to erosion and extreme storms would destory the bank of terrace. In the study site sesonal rainfall increased and the loess terrace could retain more soil water and reduce the runoff.

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)?

Comments:

The yield of terrace is stable and relative higher. The income from terrace is high and the maintain cost is low.

6.5 Adoption of the Technology

• 1-10%

If available, quantify (no. of households and/ or area covered):

100 households

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

• 0-10%

Comments:

90% of land user families have adopted the Technology with external material support

95 land user families have adopted the Technology with external material support

Comments on acceptance with external material support: Most land farmers have some terrace. I do not know the exact number of land user families who adopted the technology.

10% of land user families have adopted the Technology without any external material support

5 land user families have adopted the Technology without any external material support

Comments on spontaneous adoption: the old narrow terraces, now a very small area left, are build voluntarily.

There is a strong trend towards spontaneous adoption of the Technology

Comments on adoption trend: Nearly all the people know the benefit of terrace. the benefits of terraces are very good for crops and orchards are high enough in this region.

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Increase yield and income. How can they be sustained / enhanced? If the terrace is maintained well, the water condition would be better than that on the slope land even in dry year with low precipitation.
Convenient to till and harvest How can they be sustained / enhanced? Tillage and harvesting is much easier on the plain flat land than on the slope. The maintainance of terrace is important.

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Reduce soil erosion on the slope. How can they be sustained / enhanced? The loess soil is prone to erosion because of its loose character induced by fine sand content and low soil organic matter. The plain flat makes the dispersion and transportation of soil particls difficult.
Reduce runoff and increase the soil moisture How can they be sustained / enhanced? The runoff generation is smaller on the plain than on the slope. Slow movement of surface water lead to more soil infiltration.
Increase yield. How can they be sustained / enhanced? Water is the limit factor in the loess plateau. The yield would increase if there is enough water available.
Decrease flood risk. How can they be sustained / enhanced? It is a kind of off-site benefits because less runoff generation and gentle process of runoff decrease flooding. Reduction of sediment also diminish flood risk because the drainage capacity of channel and adjusting capacity of reservior increase when sedimentation decrease.

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?
The output is also low in contrast with other industries.	No way to overcome it. The total and net income is too low because the area of terrace per capita is very small.
The income is relative compared with other industries.	No way to overcome it. The net income is low because the labour costs are increasing, and the total income because labour cost and very small area of terrace per capita.

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
There is possible damage of terraces because the loess is very loosen and prone to collapse.	Keep upmaintaining the bank and land well.
Decrease runoff of lower stream.	No way to overcome it, but it also could decrease the risk of floods.

7.2 References to available publications

Title, author, year, ISBN:

Soil and water conservation records of Shaanxi Province. 2000. Shaanxi People's Press, Xi'an City, China

Available from where? Costs?

Library of ISWC, CAS

Title, author, year, ISBN:

The soil and agriculture of the Loess Plateau. 1989. Zhu Xianmo, Agriculture Press, Beijing City, China

Available from where? Costs?

Library of ISWC, CAS

Title, author, year, ISBN:

Statistical tearbook of Yan'an. 2003. Compiled by Editorial Board of Statistical tearbook of Yan'an

Available from where? Costs?

Library of ISWC, CAS

Title, author, year, ISBN:

Impact of human activities on runoff and sediment change of Yanhe River based on the periods divided by sediment concentration. 2008. WANG Fei , MU Xing-min ,JIAO Ju-ying, LI Rui. Journal of Sediment Research

Available from where? Costs?

http://159.226.100.28/asp/Detail.asp

Title, author, year, ISBN:

Changes of soil erosion intensity due to conversion of farmland to forest and grassland in Yanhe River. 2007. BasinWang Bangwen, yang Qinke, Liu Zhihong, Meng Qingxiang, Science of Soil and Water Conservation

Available from where? Costs?

http://159.226.100.28/asp/Detail.asp