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

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

OPtimal strategies to retAIN and re-use water and nutrients in small agricultural catchments across different soil-climatic regions in Europe (OPTAIN)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

Helmholtz Centre for Environmental Research (UFZ) - Germany

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:

A grassed waterway is a strip of grass and other permanent low growing vegetation that is established along in the main drainage line (the thalweg) of an agricultural field to discharge water safely and prevent gully development.

2.2 Detailed description of the Technology

Description:

In order to prevent gully erosion along main drainage lines (thalwegs), grassed waterways, composed of grass and other permanent low growing vegetation, are established to discharge water safely. The grassed waterway slows down the surface runoff in the thalweg, increases infiltration and stabilizes the soil surface. This reduces soil erosion by water and the associated runoff of nutrients and pesticides. Fiener et al. (2005) reported a sediment retention of 80-95% and a water retention of 70-90%. Sediment is trapped mainly by water infiltration (infiltration-induced sedimentation) rather than by the filtering effect of vegetation. The conservation value of grassed waterways is not as high as for other measures, but they are still considered as a biotope network as well as a habitat for grassland breeders when extensive management practices are used (LfULG, 2010).
Grassed waterways are typically installed in relatively large arable fields. Normally only the most vulnerable lowest area of the field needs to be grassed. The width of the area to be grassed depends on the size of the drained catchment, the physiographic characteristics of the discharge pathway (channel shape, bottom slope) and the land management (e.g. working width of the agricultural machinery). The United States Department of Agriculture (2020) recommends a total width of the grassed waterway of about 6 m in the upper part and 15 m in the lower part. On average, a grassed waterway should occupy 2% of the catchment area (LfULG, 2015).
During the establishment of the vegetation, it is recommended to protect and stabilize the young plants against strong water flows, by temporary measures such as silt fences or mulching. Once the vegetation is dense enough to withstand heavy rain events, these temporary measures should be removed. After each heavy rainfall event, the waterway should be inspected for damage. Damaged areas should be filled and reseeded, and sediment deposits should be removed.
The choice of the seed mixture depends on the intended use and maintenance of the grassed waterway. A combination of trees and grass increases infiltration rates and natural values. Mowing should be done at least once a year, otherwise, shrubs will establish and suppress the grass. The grassed waterway should not be used as a track for vehicles because of soil compaction, and damage to vegetation. Where possible, tillage should be across the slope – therefore perpendicular to the grassed waterway in order to avoid furrows developing parallel to the waterway. A combination with conservation tillage or other erosion control practices is highly recommended (LfULG, 2010).
Grassed waterways involve a permanent change in land-use, which means a loss of cultivable area, and associated loss of yield - and of income too if it is not covered by subsidies. Many land users dislike such structures in their fields as they impede machinery. Because land users are not always the landowners, they are not always allowed to make permanent changes in land-use. In Germany, a grassland becomes permanent after 5 years. Thus, many farmers decide to plough and replant such grassed areas every 5 years.

The landowner in our documentation had suffered from lodging of his oat crop along the drainage path due to heavy rainfall. Thus, he decided to undesow the oats with ryegrass. In the following year, the undersown ryegrass developed better than the oats and the farmer decided to establish ryegrass as the main crop over the whole field – rather then just in the thalweg, to avoid having to drive around it. Now he mows the area once in the spring for silage and then uses it as pasture for his horses. Every five years, he has to plough the whole area and replant it with ryegrass to prevent it from becoming permanent grassland.

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

Indicate year of implementation:

2022

If precise year is not known, indicate approximate date:

• less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through land users' innovation

Comments (type of project, etc.):

Initially, perennial ryegrass was used as an undersown crop to oats as a greening requirement of German agricultural policy. Later, the farmer decided to establish ryegrass as the main crop, including the discharge pathway.

3.1 Main purpose(s) of the Technology

• reduce, prevent, restore land degradation
• protect a watershed/ downstream areas – in combination with other Technologies
• preserve/ improve biodiversity
• adapt to climate change/ extremes and its impacts

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

Land use mixed within the same land unit:

Yes

Specify mixed land use (crops/ grazing/ trees):

• Agro-pastoralism (incl. integrated crop-livestock)

Comments:

The actual use of the grassed waterway can be very different and also depends on its dimensions. In the documented example the grassed waterway was partially used for extensive grazing (horses).

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:

• rainfed

3.5 SLM group to which the Technology belongs

• improved ground/ vegetation cover
• water diversion and drainage

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:

• prevent land degradation
• reduce land degradation

4.1 Technical drawing of the Technology

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology area

other/ national currency (specify):

€

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

0.91

4.3 Establishment activities

	Activity	Timing (season)
1.	reseeding of ryegrass (drill seed)	spring
2.	rolling (soil contact between plant and soil)	spring

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	seeding	ha	1.0	20.19	20.19	100.0
Labour	rolling	ha	1.0	19.58	19.58	100.0
Plant material	seeds	ha	1.0	32.4	32.4	100.0
Total costs for establishment of the Technology					72.17
Total costs for establishment of the Technology in USD					79.31

Comments:

Based on a new subsidy programme (valid from 2023), the establishment and 5-year maintenance of a grassed waterways will be subsidised with 299€/ha in Saxony (Germany): https://www.smekul.sachsen.de/foerderung/download/Steckbrief_AL_1.pdf
This also partially compensates for the loss of yield and income.

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	mulching	every spring
2.	ploughing	every 5 years
3.	reseeding	every 5 years

Comments:

In Germany, grassland must be removed after 5 years (by ploughing or using chemicals) and then reseeded. Otherwise it becomes permanent grassland.

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	mulching	ha	1.0	24.87	24.87	100.0
Labour	ploughing	ha	0.2	63.56	12.71	100.0
Labour	reseeding	ha	0.2	39.77	7.95	100.0
Plant material	seeds	32,4	0.2	32.4	6.48	100.0
Total costs for maintenance of the Technology					52.01
Total costs for maintenance of the Technology in USD					57.15

Comments:

Maintenance costs related to ploughing and reseeding are only required every five years. Therefore, they are based on the implementation costs and divided by 5.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Landowners complained that the additional yield (grass as fodder) would have no impact on their income. The loss of income due to the loss of arable land is greater and should be compensated by subsidy programs.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• concave situations

Comments and further specifications on topography:

A grassed waterway is a strip of grassland (permanent vegetation close to the ground) established in the line of the lowest elevation (thalweg) of an agricultural field.

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.

Luvisol (German soil classification system: Pseudogley Parabraunerde)

5.4 Water availability and quality

Is water salinity a problem?

No

Is flooding of the area occurring?

No

Comments and further specifications on water quality and quantity:

Heavy rainfall events cause flooding in the thalweg and erosion on the hillsides of the arable land. The field with the grassed waterway has had repeated erosion problems, with soil material being washed onto the adjacent road.

5.5 Biodiversity

Comments and further specifications on biodiversity:

Only one species is planted, but compared to oats, long-term grassland provides higher habitat quality and slightly higher biodiversity. The presence of shrubs and trees in the grassed waterway can further increase habitat diversity and species variety.

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

The landowner's son is studying agriculture, and the father is open to trying out the new knowledge on his land.

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:

• individual, not titled

Land use rights:

• leased
• individual

Water use rights:

• communal (organized)

Are land use rights based on a traditional legal system?

No

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Ecological impacts

Water cycle/ runoff

Soil

Biodiversity: vegetation, animals

Climate and disaster risk reduction

Specify assessment of on-site impacts (measurements):

The reported on-site impacts are estimates of the respondents and are not based on measurements.

6.2 Off-site impacts the Technology has shown

Specify assessment of off-site impacts (measurements):

The reported on-site impacts are estimates of the respondents and of the compilers. They are not based on local measurements.

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	increase or decrease	How does the Technology cope with it?
seasonal temperature	spring	increase	well

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local rainstorm	well

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

• single cases/ experimental

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?

No

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Compared to other erosion control measures, the area of the grassed waterway can continue to be used (extensively) for forage and grazing.
In Germany, the greened areas could be used as required greening areas for the direct payments of the agricultural policy.

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Grassed waterways are highly recommended and beneficial in preventing on-site gully erosion and off-site pollution of water bodies.
Due to their more technical background, the conservation value is not as high as for other measures, but they are still considered as a biotope network as well as a habitat for grassland breeders when extensively managed.

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?
In Germany, grassland becomes permanent if it is not converted within five years. This often leads to a conflict of interest between landowners and land-users. A permanent change in land-use (from arable land to permanent grassland) would mean a loss in land value.	As a result, the farmers plough and reseed the area after five years. With a change in regulations for certain measures, e.g. if land is used for nature conservation, it could remain cropland after five years without being converted.
A structure in the middle of a field is impractical in terms of tracks for machinery.	Sometimes it may be beneficial to green the entire field or subdivide the field with a linear structure.

7.1 Methods/ sources of information

7.3 Links to relevant online information

Title/ description:

LfULG (2010): Erosionsschutz in reliefbedingten Abflussbahnen, Schriftenreihe, Heft 13

URL:

https://www.boden.sachsen.de/erosionsschutz-in-reliefbedingten-abflussbahnen-18074.html

Title/ description:

United States Department of Agriculture (2020): Grassed Waterway - Conservation Practice Standard

URL:

https://www.nrcs.usda.gov/resources/guides-and-instructions/grassed-waterway-ac-412-conservation-practice-standard

Title/ description:

LfULG (2015): Begrünung von erosionsgefährdeten Abflussbahnen. Broschüre

URL:

https://publikationen.sachsen.de/bdb/artikel/23739

Title/ description:

Fiener & Auerswald (2006): Seasonal variation of grassed waterway effectiveness in reducing runoff and sediment delivery from agricultural watersheds in temperate Europe. Soil and Tillage Research 87, 48–58.

URL:

https://doi.org/10.1016/j.still.2005.02.035

Title/ description:

Wasserhaushaltsportal Sachsen: KLiWES 2.1 IST-Zustand 1988-2015

URL:

https://whh-kliwes.de/mapview