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)

Integration of cover crops into field crop rotation - Slovenia (EIP-AGRI)

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

Chamber of Agriculture and Forestry of Slovenia – Institute of Agriculture and Forestry Maribor (KGZS) - Slovenia

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:

Crimson clover, overwintered as a cover crop, forms a symbiotic relationship with nitrogen-fixing bacteria, capturing nitrogen and thus enriching the soil. This helps reduce the need for synthetic fertilizers and aids in soil erosion control, weed suppression, and improved soil structure.

2.2 Detailed description of the Technology

Description:

Crimson clover (Trifolium incarnatum) is a winter annual legume used as a cover crop for nitrogen fixation, erosion control, and soil improvement. It is well suited to mild winter climates and can be integrated into various farming systems. It can be sown alone or in mixtures after the main crop is harvested. It covers the soil from late summer until spring and can be used as fodder or for green manure.
Its key function is nitrogen fixation through the help of nitrogen-fixing bacteria (Rhizobium). Through the winter it protects the soil from erosion, prevents nutrient leaching, and helps suppress weeds. The deep root system improves soil aeration and drainage. When terminated, it adds organic matter and nutrients to the soil, and its nectar-rich flowers attract pollinators and provide a habitat for beneficial predatory insects.
Crimson clover is often included in multi-year crop rotations. Activities include light tillage or no-till. Sowing usually takes place in late August to early September - or at least 6 to 8 weeks before the first frost. Fertilization with mineral nitrogen is not required, but phosphorus and potassium can help in establishment. Minimal maintenance is needed as these plants suppress weeds and reduce pests, but some fungal diseases may occur in wet conditions. Termination involves mowing or rolling at 50% bloom and then herbicides, or it can be incorporated as green manure.
Farmers value crimson clover for its multiple benefits including cost savings from reduced fertilizer use. Livestock farmers use it for forage. Some challenges may arise in colder climates, and when the soil is wet or compacted.
Under trials, the use of crimson clover as a cover crop to supply nitrogen was compared with a ryegrass cover crop and with fallow land, where no cover crops were used. The seeds were sown during two periods—early (August) and late (September)—and the cover crops were not further fertilized. The cover crops were terminated before sowing maize. The fallow area and the ryegrass area were fertilized according to the requirements of maize (215 kg N/ha) and soil analysis (for P and K). Half of the crimson clover area received no N fertilization, and the other half received only half of the required N. The maize crop was monitored by measuring soil, maize growth, grain yield, whole plant weight, and root weight. Crimson clover contributed between 61.6 and 78.6 kg of symbiotically fixed N ha⁻¹. The total soil amount of N accumulated by crimson clover was 100.7 kg N ha⁻¹, twice as much as under Italian ryegrass. The maize grain yields were significantly the lowest (10.9 t DM grain ha⁻¹) where crimson clover was sown early and the maize received no additional N. When crimson clover was used and maize was fertilized with half the N rate, grain yields were equivalent to those obtained on plots that received the full N rate (Italian ryegrass 13.5 t DM ha⁻¹, and the bare fallow control 13.4 t DM ha⁻¹).

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:

2024

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through land users' innovation
• during experiments/ research
• through projects/ external interventions

Comments (type of project, etc.):

The European Innovation Partnership (EIP) projects for agricultural productivity and sustainability (EIP-AGRI) enable exchange of knowledge for agriculture, forestry, and rural areas. The technology was introduced on these farms through the EIP project: "Integration of Cover Crops in Crop Rotation – Possibilities for Replacing Nitrogen from Mineral Fertilizers in Fertilization of the Next Crop"

3.1 Main purpose(s) of the Technology

• improve production
• reduce, prevent, restore land degradation
• preserve/ improve biodiversity
• adapt to climate change/ extremes and its impacts
• 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?

• No (Continue with question 3.4)

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
• integrated soil fertility management

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

Comments:

Although primary cause of technology is natural nitrogen supply, the technology indirectly addressed also the soul erosion.

3.8 Prevention, reduction, or restoration of land degradation

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

• prevent 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):

EUR

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

0.85

4.3 Establishment activities

Comments:

None

4.4 Costs and inputs needed for establishment

Comments:

None

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	Stubble preparation (tillage) for crimson clover + sowing (stages 1 and 2 in diagram)	August (or September)
2.	Mechanical cover crop termination and soil preparation before maize sowing (stage 3 in diagram)	end of April
3.	Sowing of maize (stage 4 in diagram)	May
4.	Fertilisation (part of stage 4 in diagram)	May, June
5.	Hoeing and weed control (herbicide) (stage 5 in diagram)	May, June
6.	Harvest (maize) (stage 6 in diagram)	October
7.	Drying (maize) (part of stage 6 in diagram)	October

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	All labour costs	hour	6.0	15.0	90.0	100.0
Equipment	Stubble preparation for crimson clover (tillage)	ha	1.0	50.0	50.0	100.0
Equipment	Sowing of crimson clover	ha	1.0	46.3	46.3	100.0
Equipment	Mechanical termination of the crimson clover	ha	1.0	37.5	37.5	100.0
Equipment	Tillage and seed bed preparation for maize	ha	1.0	60.0	60.0	100.0
Equipment	Maize sowing	ha	1.0	60.0	60.0	100.0
Equipment	Maize hoeing and weed control	ha	1.0	60.0	60.0	100.0
Equipment	Maize harvesting	ha	1.0	140.0	140.0	100.0
Plant material	Crimson clover seed	ha	28.0	3.5	98.0	100.0
Plant material	Maize seed	ha	1.0	290.0	290.0	100.0
Fertilizers and biocides	Fertilizer	ha	1.0	150.0	150.0	100.0
Fertilizers and biocides	Herbicide	ha	1.0	80.0	80.0	100.0
Other	Drying of maize grain	all harvest	1.0	428.0	428.0	100.0
Total costs for maintenance of the Technology					1589.8
Total costs for maintenance of the Technology in USD					1870.35

If you are unable to break down the costs in the table above, give an estimation of the total costs of maintaining the Technology:

1561.8

Comments:

The above calculation is for combination of crimson clover cover crop and half the amount of nitrogen fertilizer (107 kg/ha) for maize production. This technology had similar grain production (13.7 t/ha) as full application of mineral nitrogen (215 kg/ha) with combination of fallow land or ryegrass as cover crop. The revenue for this technology from selling the grain was 2877 €/ha (0.21 €/kg). Crimson clover with no additional mineral fertilisation for maize had significantly lower yields (10.9 t/ha) and thus lower revenue per hectare (2289 €/ha; 0.21 €/kg of grain). For crops which need less nitrogen than corn, the additional mineral N fertilisation would not be necessary and so costs would be lower. Farmers get 180 € of basic subsidies per ha and further 148 € per ha for greening through the winter (EU CAP).

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Most important factors affecting the costs are the price of seeds and machinery hours.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• not relevant

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.

The test fields were on different soil types:
- Eutric alluvial soils pH 6,6-7,2
- Dystric brown soils on non calcareous sandy gravel sediments, pH4,6-5,5
- Eutric brown soils on alluvial-colluvial sediments and deluvium, pH 5,6-6,5

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:

In Slovenia all drinking water is treated by chlorine. If we compare it to the rest of the world, we have good drinking water, but we never use it untreated.

5.5 Biodiversity

Comments and further specifications on biodiversity:

Under the cover crop area soil biodiversity is high. Regarding overall habitat, the test areas are in intensive agricultural areas, that is why the habitat biodiversity which is otherwise high in Slovenia, is rated as moderate.

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
• individual, titled

Land use rights:

• leased
• individual

Water use rights:

• communal (organized)
• leased

Are land use rights based on a traditional legal system?

No

Specify:

Land use rights in Slovenia are primarily based on modern statutory law, not traditional or customary law. The main frameworks are the Constitution of the Republic of Slovenia, the Law of Property Code (Stvarnopravni zakonik, SPZ), the Agricultural Land Act (Zakon o kmetijskih zemljiščih, ZKZ), and the Spatial Planning and Building Acts (Zakon o urejanju prostora, Gradbeni zakon, etc.).

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):

On-site impacts included direct field measurements and expert judgements/ predictions on the basis of data from this and previous experiments.

6.2 Off-site impacts the Technology has shown

Specify assessment of off-site impacts (measurements):

Off-site impacts are predicted by expert judgements/ predictions on the basis of data from this and previous experiments.

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	summer	increase	moderately
seasonal temperature	winter	increase	well
seasonal rainfall	summer	decrease	not well
seasonal rainfall	winter	decrease	moderately

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local hailstorm	moderately

Climatological disasters

	How does the Technology cope with it?
heatwave	not well
drought	not well

Biological disasters

	How does the Technology cope with it?
insect/ worm infestation	well

6.4 Cost-benefit analysis

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

6.5 Adoption of the Technology

• 1-10%

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

• 0-10%

Comments:

They are mostly motivated by subsidies, so spontaneous adoption is a small percentage.

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
Lower costs for mineral fertilizers, subsidies for seeds
Good for soil health
Good for water absorption

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Climate change adaptation
Soil improvement - increase in organic matter, soil biodiversity, water capacity
Fixation of nitrogen form air, less mineral fertilisers

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?
Drought during the seeding of catch crop	earlier or later sowing - however it has an impact anyway
Additional work (compared to bare fallow)	combined machinery (soil preparation + sowing combined)
Risk of frost if the crimson clover is too big going into winter	sowing and mulching at right time

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
Not applicable for all main crops - early spring crops do not get the same benefits as late spring/summer crops	for early spring crops other nitrogen fixings plants can be used.
Nitrogen runoff if no main crop follows after crimson clover destruction	always plant main crop right away

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

GSELMAN, Anastazija, LISEC, Urška, KOROŠEC, Tamara, PODVRŠNIK, Miran. S prezimnimi metuljnicami do nadomeščanja dušika iz mineralnih gnojil = Winter legumes as a substitute for nitrogen from mineral fertilisers. V: ČEH, Tatjana (ur.), KAPUN, Stanko (ur.). 32. mednarodno znanstveno posvetovanje o prehrani domačih živali [tudi] Zadravčevi-Erjavčevi dnevi 2024 = 32nd International Scientific Symposium on Nutrition of Farm Animals [being] Zadravec-Erjavec Days 2024 : zbornik predavanj = proceedings : Murska Sobota, 14. in 15. november 2024, 14th and 15th November 2024. Murska Sobota: Kmetijsko gozdarska zbornica Slovenije, Kmetijsko gozdarski zavod, 2024. Str. 61-66, graf. prikazi. ISBN 978-961-96187-7-6. [COBISS.SI-ID 215866371]

Available from where? Costs?

in various Slovenian libraries - in Slovene

7.3 Links to relevant online information

Title/ description:

Website

URL:

https://dosevki.um.si/

7.4 General comments

Just a remark on question formulation: the instructions in section 6.1 appear a bit ambiguous when the response scale for some specific questions appears "reversed" in relation to the guideline parameter - such as "soil crusting" where a negative value is in fact a positive outcome.