Row-based agriculture with reduced chemical plant protection and promotion of beneficial insects and wild herbs in the field (ReNuWi)
Worldwide, the intensification of agriculture and the resulting use of synthetic chemical pesticides are considered to be one of the main causes of biodiversity loss. Biological diversity is the basis for important ecosystem services such as soil fertility, pollination, and pest control. Herbicides and insecticides generally have a non-specific effect on harmful organisms and beneficial insects, resulting in negative feedback effects as the increasing loss of natural enemies leads to an increase in weed and insect pest pressure. In order to break this vicious circle, measures to strengthen biodiversity are essential in addition to reducing the use of synthetic chemical pesticides. The overarching goal must be to reduce the use of synthetic chemical pesticides, to ensure technical feasibility and, at the same time, to minimize losses in yield and quality.
Project priorities
- Reduction of chemical-synthetic plant protection in conventional agriculture through the combination of high-precision mechanical and chemical plant protection methods.
- Reduction in fungicide use by redesigning crop architecture and—where plant protection is still required—using application technology that targets specific areas of infestation.
- Integration of native wild herbs into conventionally farmed land as living mulch to suppress weeds, increase biodiversity, and promote beneficial organisms.
- Maintaining and improving soil health and thus plant fitness through permanent and diverse plant growth and the absence of chemical synthetic pesticides.
- Assessment of the economic feasibility of these innovative methods compared to conventional land management on medium-sized farms.
Project region
Salzlandkreis
Further project details
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IIn a large-scale plot trial repeated four times, winter wheat, corn, field beans, and winter durum are being established using strip-till cultivation. The trial plots are each 9 x 47 m in size, randomized, and cultivated using conventional techniques. In strip tillage, the crops are grown at a distance of 50 cm. Maize and field beans are grown in single rows, cereals in double rows. The area between the crop rows remains uncultivated and, depending on the variant, is kept free of weeds chemically or mechanically or prepared for targeted sowing of crop and wild herb mixtures (see WP2).
Sowing and fertilization take place according to regional experience or in accordance with fertilizer requirements as determined by the Fertilizer Ordinance. Plant protection is based on the variants of work package 2.Responsible: Deutsche Landwirtschaftsgesellschaft
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Building on experience gained from other projects, wild herb mixtures adapted to arable crops are being developed and sown under practical conditions in the inter-rows of the strip-till cultivation system. In comparison, conventional cultivation methods and crop mixtures are also being tested:
- Option 1 – Conventional, chemical-synthetic plant protection without inter-row vegetation [herbicide]
- Option 2 – Mechanical weed control between rows without intercropping [hoe]
- Option 3 – Field crop-specific, annual crop mixture as inter-row vegetation (1-3 species) [einjKult]
- Variant 4 – Field crop-specific, annual wild herb mixture as inter-row vegetation (5-10 species) [einjWK]
- Variant 5 – Perennial wild herb mixture of 15 species as inter-row vegetation [mehrjWK15]
- Variant 6 – Species-rich perennial wild herb mixture comprising 25 species for inter-row greening [mehrjWK25]
The aim is to use the established vegetation in the inter-rows as living mulch and as a biological plant protection measure (promotion of beneficial organisms) in order to reduce the use of synthetic chemical agents to the necessary minimum. In all of the variants mentioned, the use of synthetic chemical pesticides can be applied in the crop rows depending on the applicable damage thresholds using high-precision band spraying, without affecting the vegetation in the inter-rows.
Responsible: all partners
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The basic equipment provided for the project consists of a 3 m Schmotzer hoeing machine (6 rows, 50 cm each) with mulching tools and an Amazone front tank (FT-P 1502) as a field sprayer with band spraying equipment. The hoeing machine also has a seed hopper (Green-Drill) for the precise metering and placement of seed mixtures between the rows of crops.
As part of the project, new row-oriented knife rollers are being developed to reduce the growth of living mulch (vegetation from sown wild herbs and spontaneously emerging species) in 50 cm strip cultivation. These devices and tools are used and maintained on site in the respective crops by experts from Schmotzer Hacktechnik. The knowledge gained from practical applications will be incorporated into the further development of the machines.
Dropleg nozzle systems are provided for the Amazone UF crop protection sprayer available at the International Plant Production Center (IPZ) and adapted to the changed crop architecture. The conversion requires both partial deactivation of existing spray nozzles and an adjustment option for the farmer depending on the crop height. Both must be operationally feasible so that the conversion can be carried out quickly and safely during the growing season. The dropleg system allows pesticides to be applied laterally to the crop without wetting the inter-rows.Responsible: Schmotzer Hacktechnik
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Work package 4.1: Crops and pests (DLG)
The crops maize, field beans, winter wheat, and winter durum are established in the field at times typical for the region and appropriate to the location. The crops are assessed according to their growth development and closely monitored until harvest for nutrient requirements, disease and pest occurrence, and important yield factors. A final yield and quality assessment is carried out. The assessments allow any competitive effects on the living mulch to be identified, but also take into account effects on disease or pest development.
Work package 4.2: Wild herbs and beneficial organisms (HSA)
After the trial has been implemented, regular assessments are carried out of the developing vegetation and selected groups of beneficial organisms in the inter-rows. In all variants, the total coverage and average height of the vegetation, the species composition, and the flowering phenology are recorded on permanent plots. For selected beneficial insect groups (e.g., hoverflies, wild bees), flower use will be documented on subplots. Ground beetles and spiders will be recorded using ground traps (twice a week in June/July), while wild bees and hoverflies will be recorded using the net method (five times between April and August).
Adonis aestivalis 
Centaurea cyanus 
Anthemis tinctoria 
Consolida regalis 
Linaria vulgaris 
Viola arvensis (Foto: M. Bullau) Work package 4.3: Soil (DLG)
Changes in farming systems, particularly those involving the integration of different plant communities and types and periods of cover, have an impact on soil parameters. The following soil parameters are examined in order to record these changes:
- Nutrient content (N, P, K) at soil depths of 0–30 cm, 30–60 cm, and 60–90 cm (VDLUFA standard)
- Humus content at a soil depth of 0–30 cm (according to VDLUFA laboratory standard)
- Microbial activity using the tea bag method [Tea Bag Index – TBI] (Sandén 2019)
Work package 4.4: Plant protection (DLG)
The main objective of the project is to reduce the use of synthetic chemical pesticides. The effective reduction is being investigated by comparing the use of appropriate active ingredients at the same location. In order to obtain meaningful information about the actual environmental impact of the changed use of pesticides, the following parameters are recorded for each variant and crop and then evaluated in relation to each other:
- Time of reaching relevant damage thresholds
- Type of action (herbicide, fungicide, insecticide, growth regulator)
- group of active substances
- Time of application of an active substance
- Amount of active substance used
- Percentage of treated area
- working success
Work package 4.5: Economic efficiency (DLG/Schmotzer Hacktechnik)
Due to the practical implementation of the issue via large-scale trials and the use of commercially available machinery, as well as the recording of all costs and revenues, an economic evaluation of all variants can be carried out.
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The results of the project are to be integrated into practice. Regular knowledge exchange between the project partners and targeted public relations work are intended to promote this. Presentations at specialist events such as trade fairs and conferences serve as multipliers for knowledge transfer. In addition, information is disseminated through various media, including scientific journals, trade magazines, and social media.