Title : 
 Maßnahmen zur Reduzierung des Pflanzenschutzmitteleinsatzes - Anpassungsoptionen , Kosten und Möglichkeiten zur umweltpolitischen Steuerung 

 Abstract : 
 Plant protection products are a significant component of conventional arable farming in Germany . They have helped increase land productivity and reduce yield losses , thereby providing a significant contribution to food security . However , plant protection products have negative impacts on biodiversity . Moreover , their degradation products can be found in ground and surface waters , and they are associated with negative effects on human health . Against this background , the aim of policy is to reduce the use of plant protection products and the associated risks . By contrast , the questions of whether and how farms can adapt their production systems and the resulting costs remain largely unanswered . Similarly , although the advantages and disadvantages of different policy implementation strategies for reducing plant protection products are discussed at both the European and national levels , the scientific publications are aimed primarily at introducing a tax model . A concrete comparison of different policy measures and an assessment of the adaptation reactions as well as the associated consequences , taking agricultural expertise into account , usually is not carried out . Against this background , based on a typical farm in the soil - climate region “ Südhannover ” and using a focus group approach with farmers and advisors , the present dissertation investigated which farm adaptation measures can reduce the risks to humans and the environment associated with the use of plant protection products by 25 % or 50 % and what adaptation costs result from such measures . The risks posed by pesticides were determined with the help of the Pesticide Load Indicator ( PLI ) . In order to be able to quantify the yield effects as a result of reduced pesticide use , regional and national trial evaluations were consulted . In addition , the expected yield effects were differentiated between a best and worst case and a “ normal year ” . In order to reduce the PLI by 25 % , farmers first will substitute less toxic active substances for those with a higher PLI . Similarly , weeds are increasingly regulated mechanically and non - selective herbicides are replaced by mechanical tillage before summer crops . If no crop - specific PLI reduction is required and alternative crops are available , farmers will substitute crops with a low net margin per PLI unit used ( e.g. rape with grain maize ) . If the PLI is halved , reduced fungicide and insecticide use across crops or later sowing dates in cereals also are suitable for reducing the risks from plant protection products . With a crop - specific PLI reduction of 25 % , changes in the net margin range from + 25 € /ha for sugar beet to – 60 € /ha for stubble wheat can be expected . If the PLI has to be reduced by 50 % for each individual crop , the range of adjustment costs among the crops increases further . While the PLI can be halved for oilseed rape with costs of about 50 € /ha , the net margin for stubble wheat or winter wheat after silage maize decreases by about 150 € /ha . At farm level , the results show that the more adaptation flexibility farmers are granted , the lower the adaptation costs . With a 25 % reduction of the PLI and taking into account the active ingredient substitution , manageable adaptation costs of between about 10 € /ha and 20 € /ha can be expected , depending on the adaptation flexibility granted . The change in grain units ( GU ) produced varies between + 4 % and – 5 % . On the other hand , the adjustment costs increase disproportionately strongly with a PLI reduction of 50 % , so that an operational net margin reduction of between about 80 € /ha and a maximum of 125 € /ha can be expected . With a PLI reduction of 50 % , the change in GU produced is between 0 and a maximum of -7 % . As farmers are in competition with their colleagues on the land and tenancy markets , they usually can not afford to voluntarily switch to production systems that cause lower yields or cost increases and thus put them at a competitive disadvantage vis - à - vis neighbouring farms . Policymakers therefore must change the framework conditions for all farms in such a way that the adaptation of production systems is either mandatory or economically viable . A wide range of policy measures are available for this purpose . Following on from the results of the adaptation costs , it therefore was examined how policymakers can use the " PLI " starting point to achieve their reduction target . In order to expose the selected policy measures and impact assessments to the critical judgement of the focus group , four concrete policy measures were developed that can achieve PLI reduction while addressing different secondary objectives . The measures examined include an individual farm PLI ceiling , a licensing system with tradable use rights , a state subsidy for low PLI hectare values and an increase in crop protection product prices depending on PLI . It was assumed that the policy measures would be introduced throughout the European Union . The effects that can be expected on production , farm incomes and the administrative and control costs for farmers and the state were worked out in an impact assessment . The following results emerged : In the case of a PLI ceiling for individual farms and at the same time for individual crops , every farm must , in principle , reduce its PLI use if it does not yet meet the targets in the initial situation . This leads to an area - wide risk reduction without shifting the production of individual crops to third countries . However , the adjustment flexibility for farmers is comparatively low compared with other policy options . The control is carried out with the help of an online database . In contrast , an increase in plant protection prices depending on the PLI has the advantage of not having to control all farms , but only " bottlenecks " such as traders and manufacturers of plant protection products . A disadvantage is the high negative income effect for the farms ( > 220 € /ha ) if the PLI is halved . In addition , readjustments of the levy level are to be expected in order to approach the reduction target . If the PLI use rights are distributed in a licensing system depending on acreage , it can be expected that crops with a high net margin per PLI unit used will be cultivated preferentially . On the other hand , crops with a low net margin per PLI unit used will increasingly be pushed out of cultivation . Farm managers can decide on the basis of the market price for the tradable PLI use rights whether to use them themselves on the farm or sell them on the market . As a result , it is to be expected that PLI units will be saved , especially on marginal arable sites where this saving causes only low costs . The PLI units freed up there move primarily to regions where an above - average net margin per PLI unit can be produced . These are classically favourable locations for arable farming . The comparatively high administrative costs required for tradability must be viewed critically . For the state , this additional effort goes hand in hand with the advantage that the reduction target can be targeted precisely . If the state decides to promote low PLI hectare values with a premium , a negative income effect at farm level can be prevented , as the farm only participates if its costs are lower than the premium payment . The acceptance of the policy measure by farmers is high . A major challenge , however , is the controllability , as there are high incentives to undermine the system .