Browsing by Author "Vetter, A."
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- Evolution of crop yields and qualities in a short rotation coppice alley cropping system in Central GermanyPublication . Jung, L.; Barwolff, M.; Vetter, A.A modern form of agroforestry are alley cropping systems where annual field crops are grown in combination with strips of fast-growing tree species, so-called short rotation coppices (SRCs). Besides fulfilling the farmers requirements to keep the field in the state of production, SRC strips provide many of the well-known positive functions of hedges. They act as wind shelter, reducing soil erosion. By influencing microclimate, they can balance out short periods of extreme climatic conditions leading to higher and more stable biomass yields of the field crops. Furthermore, they may affect quality parameters of crops and disease pressure. SRCs increase the structural and habitat diversity in the landscape, thus promoting biodiversity. Studies on these various aspects are carried out in five agroforestry systems (AFS) within the joint project “AgroForstEnergie”, funded by the Federal Ministry of Food and Agriculture, Germany, since 2007. The sub-project of the Thuringian State Institute of Agriculture focuses on influences on crop yield and quality. Crop yield data were collected by GPS-equipped harvesters and evaluated with the software ArcGIS. Along a transect with defined distances from SRC strips, we recorded data on crop quality and fungus infection rate and conducted vegetation surveys. Results showed a reduction of wheat and barley yields in close vicinity to SRC strips and an increase towards the middle of the field. No such pattern was observed for rape seed. Increased fungus infections and effects on quality parameters were found in some years, but only in the immediate SRC strip vicinity. SRC strips had a much higher plant species richness than field strips, showing their valuable contribution to an increase in biodiversity. The weed pressure on adjacent crops strips was comparable to the one found along conventional field edges.
- Short rotation coppices along watercourses - an innovative combination of sustainable agriculture and water protectionPublication . Furstenau, C.; Vetter, A.The multiple advantages of short rotation coppices (SRC) such as sustainable energy wood production, income diversification, and ecological services are well known and investigated in various projects. Additionally, strips of SRC present an innovative instrument to buffer nutrient and pesticide contamination of watercourses induced by soil erosion. Through extensive management, provision of permanent plant cover, soil improvement, and long rotations, SRC-strips on arable land could help to achieve the goals of the EU Water Framework Directive (i.e., reduction of nutrient contamination of water bodies). In comparison to near-natural buffer strips, SRC also provides monetary benefits for farmers and therefore is a sustainable combination of agriculture production and water pollution control. SRC-strips represent a special form of agroforestry systems. From the aspect of erosion control and runoff reduction, strips should have a width of 12 - 18 m; therefore, the SRC-strips are small in comparison to conventional SRCs. This circumstance requires adapted planting strategies such as a reduced tree number (3.000 trees/ha), a rotation period of at least 10 years and manual harvest to optimise labour input and revenues. The project “Short rotation coppice along a watercourse” investigates the anticipated environmental advantages of SRC-strips. The study site, installed in 2011, is situated near Wolferschwenda in Thuringia on the edge of a field, slightly sloping towards the Bennebach stream. The experiment compares three management options for the buffer strip: cropland, grassland, and SRC (willow). Two main objectives of the project are (i) simulation of potential soil input by erosion on the study site under different crops and (ii) investigation of the retention capacity of SRC, grassland, and cropland. Intensive soil measurements carried out from 2012 until present show initial trends that SRC may be a more effective nutrient buffer than grassland. More detailed results are expected from irrigation experiments in spring 2014.