Summary
The use of chemical pest management products has become an essential component of modern, competitive crop management strategies in arable farming. However, in Europe farmers are obliged to reduce pesticide use. The pesticide use intensity are influenced by local environmental factors like natural production conditions as well as weather conditions in the year of cultivation. Data collections on chemical plant protection measures, like NEP-TUN-surveys and the Network of reference farms for plant protection, have shown regional differences in pesticide use intensity in Germany. Further analyses about on-farm pesticide use also show a high variability between farms under similar conditions.
The aim of this dissertation was to investigate the contribution of regional and farm effects to average pesticide use and its variability as well as separate and quantify main influential fac-tors on the pesticide use intensity in arable farming. For this purpose, in this study a compre-hensive collection of agricultural on-farm data in the framework of an inter-regional monitor-ing of pesticides in Northern Germany was analysed. The enormous amount of data collect-ed for this study enables investigations on the effects of different production intensities on the pesticide use intensity in arable farming. Furthermore, there was a need to separate regional and annual influences from the farm effect to identify farm-specific determinants for the in-tensity of pesticide use. It was investigated which farm characteristics and pesticide man-agement factors are related to lower or higher pesticide use intensity. A further aim was to investigate the influence of crop management factors like the combined effect of crop rotation and tillage on fungicide and herbicide use intensity.
The field records of 60 farms in four regions of Northern Germany (Diepholz, Uelzen, Fläming, Oder-Spree) were examined for twelve field crops between 2005 and 2014. Overall, 100,000 plant protection measure on 19,876 fields were recorded. The regions correspond to administrative districts of similar size located on a gradient of climatic, soil, and structural production conditions. I analysed pesticide use intensity described as Standardised Treatment Index (STI) and used multiple regressions to estimate the relationship between farm characteristics and pesticide use.
The results showed a decreasing gradient in pesticide use intensity from the west to the east in Northern Germany. Pesticide use intensity in most crops differs substantially between the study districts. STIs were lower in districts with less favourable conditions for arable land use, except for glyphosate use intensity. However, analysis of variance components showed that the influence of the natural gradient is smaller than the influence of the farm. Hence, differ-ences in farm management and socio-economic characteristics are more influential than production conditions. Furthermore, the results demonstrate that pesticide use will be affect-ed by farm-specific factors; the variability of glyphosate use was mainly influenced by the factor farm. At the regional and farm levels, pesticide use intensities are strongly related to productivity. These results are largely in agreement with previous investigations into multi-year and multi-region comparisons of the variability of applying chemical plant protection; however, they are supported by a substantially larger random sample of farming operations.
Pesticide use will be affected by farm-specific factors, like objectives and equipment as well as knowledge and perceptions of decision-makers. An increasing specialization in arable farming means that the pesticide use intensity will tend to rise. Farmers in the eastern dis-tricts used significantly larger amounts of glyphosate to make up for economic constraints of the farms.
Evidence has been provided that crop rotation and tillage influence fungicide and herbicide use intensity in arable farming. The results revealed that more diverse crop sequences and ploughing tillage were associated with lower usage of herbicides and fungicides. The results of the present study shall contribute to clearly identifying the main factors influencing pesti-cide use intensity in arable farming. For the first time, overlaps in the influence of the factors region and farm operation could be resolved. Furthermore, general factors influencing the pesticide use intensities were also confirmed for a large collection of farm records. Thus, the results may be useful for showing reduction potentials and the influence of preventive pesticide use measures. Notably, information was acquired through this study that shows which minimum pesticide use intensities can be achieved through corresponding crop cultivation management.