Combining Short Rotation Coppice \Vith Annual Crops Modern Agroforestry Systems for Sustainable Land Use
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19th European Biomass Conference and Exhibition, 6-10 lune 2011, Berlin, Germany COMBINING SHORT ROTATION COPPICE \VITH ANNUAL CROPS MODERN AGROFORESTRY SYSTEMS FOR SUSTAINABLE LAND USE 1 M. Bärwolff , C. Böhm 2, C. Sclunidt 3, K.-U Schwarz 4, A. Vetter 1 I Thuringian State Institute ofAgriculture, Apoldaer Straße 4, 07774 Dornburg-Camburg, Germany, Tel.: +49 36427 868-117, Fax: +49 36427 22340, [email protected] 2 Brandenburg University ofTechnology, Konrad-Wachsmann-Allee 6, 03046 Cottbus, Germany, Tel.: +49 35569-4145, Fax: +4935569-2323, [email protected] 3 Justus Liebig University, Senckenbergstraße 3, 35390 Gießen, Germany, Tel.: +49 0641 99-37244, [email protected] 4 Julius Kühn-Institute, Bundesallee 50, 38116 Braunschweig, Germany, Tel.: +49 531 596-2335, Fax: +49 531 596-2399, [email protected] ABSTRACT: The production offuelwood in short rotation coppice (SRC) is considered as one compartment in the upcoming intensification of the generation of renewable resources, which importance is undoubted in terms of reducing carbon dioxide in the atmosphere and gaining independence offossil fuels. Increased production ofbiomass for energy recovery will intensify the pressure on land, leading to further intensification ofagricultural management. Combining forestry and agricultural systems seem to be a promising solution. In a joint research project four agroforestry systems combining SRC strips and crop strips were established in Germany. Each site otTers different initial conditions for combined wood and crop production. Main focus on all sites is the evaluation of economic and ecological issues. The objective is to deduce possibilities ofimprovement and to make relevant information available for practice and consultancy. Besides economic calculations, further research fields inc1ude microc1imate, flora, fauna and soil properties. First results show significant impact on microc1imate and biodiversity. Enhancing effects on crop yields seem to be associated with specific site conditions and do not occur necessarily. Without an economic consideration of ecosystem services today SRC agroforestry systems can not compete with single crop systems, but may become economically relevant with further progress ofclimate change. Keywords: short rotation forestry (SRF), agriculture, agroforestry, sustainability, biodiversity, c1imate change INTRODUCTION In 2010 nationwide about 4000 hectare ofplants for solid fuel (mainly energy wood and miscanthus) existed [3]. The concept of silvoarable agroforestry became The joint research project "AgroForstEnergie obsolete in practical land use in Europe some hundred ,,AgroForstEnergie - economic and ecological evaluation years ago. In times of industrialisation of agricultural of agroforestry systems in farming practice", funded by practice, the ancient methods of combining trees and the German Federal Ministry of Food, Agriculture and annual crops on one site seemed redundant. To increase Consumer Protection" aims to combine both topics. It agricultural area and yield, landscape components such as was initialised to look at alley-cropping systems which hedgerows, copses and other boundary structures were combine the production of woody biomass for thermal removed. Side effects were an impairment of utilisation (short rotation coppice, SRC) with microc1imatic conditions and landscape biodiversity as conventional field crops [4]. Superordinate targets are: weIl as the enhancement of soil erosion and nitrate leaching. The theory of climate change reinforces the • Conserving productivity of the whole discussion about ecosystem services and the need for agricultural area, sustainable land use systems. With modern design, • Production of highly demanded woody agroforestry systems may provide an opportunity in bioenergy sources on agricultural area, combining sustainability and productivity in agriculture • Diversification ofagricultural production, with positive effects for environment and farmers. Previous research on the topic ofmodern agroforestry • Increase of yield stability of crops between stated possible advantages and characteristics coming SRC strips by windbreak effects, along with this special form ofagriculture [1]: • Implementation of structural elements in open landscapes to reduce erosion and increase the • Biomass productivity and profitability can be biodiversity in the agrarian landscape. higher in agroforestry than in forestry or A total of four sites in Germany (located in agricultural monocultures Thuringia, Brandenburg and Lower Saxony) were chosen • Agroforestry can be more sustainable than to evaluate economic and ecological issues. The objective forestry or agricultural monocultures is to deduce possibilities of improvement and to make • Behaviour of combined system components relevant information available for practice and (trees, crops, animals) can not be predicted from consultancy. Besides economic evaluation, further their single use research fields include microclimate, flora, fauna and soil properties. The use of fast growing trees in order to produce This paper aims in giving a glimpse into the actual woody biomass is considered as one component in the work of evaluating agroforestry systems with short German strategy to increase the share of renewable rotation coppice strips in Germany. First results will energy in overall energy supply until 2020 [2]. So far, the show tendencies of development as final statements can cultivation of fast growing trees on German agricultural only be made after observation ofa significant part ofthe area is implemented only hesitantly by German farmers. agroforestry system life span. 55 19th European Biomass Conference and Exhibition, 6-10 June 2011, Berlin, Gelll1any 2 EXPERIMENTAL DESIGN 24 meter wide alleys (cultivated with alfalfa - Medicago sativa) and 11 meter wide tree hedgerows (consisting of 2.1 Large scale cropland, Thuringia State, Germany four double rows ofblack locust - Robinia pseudoacacia; A 50 hectare field in a structurally poor and 9,200 trees ha,I). The interactions between trees and intensively agriculturally used area of Thuringia was crops will be characterized by measuring weather and chosen to establish a large-scale alley cropping system yield data in different distances from hedgerows. Based with short rotation coppice strips, Climatic site on these results recommendations for an optimization of characteristics are an average yearly precipitation of the tree-crop interaction will be developed in order to 5951 m2 and an annual average temperature mean of increase the reliability ofplant production as compared to 8,8 oe. Soil texture is characterised by high amounts of monocropping systems. silt and clay, soil type is Luvisol developed from shell limestone, ground water is not plant available. 2.3 Cropland and pasture, Lower Saxony State, Germany Planting took place in spring 2007. High yield poplar Especially on productive agricultural sites habitat clones "Max 1, 3, 4" were planted as cuttings in two structures were often removed in the course of different planting schemes (10.000 trees ha,l and intensification measurements by soil melioration. This 3.300 trees ha,I). Harvest will take place after 4 years by led to a significant deterioration of the floral and faunal a fully automatic mowing cutter and after 8 years by a biodiversity. Therefore, particular emphasis was placed feIler buncher respectively. SRC strips are arranged in the design ofthe alley cropping system established on South-North against the prevailing wind direction (West). cropland and pasture in Lower Saxony in spring 2008 in Three different distances (48,96, 144 meter) between order to maximize structural diversity. Thus, the SRC strips are tested. Additionally several native forest experimental design contains various poplar and willow species (Populus tremula, Betula pendula, Fraxinus clones that will be harvested in a 5-year rotation (poplar: excelsior, Carpinus betulus, Robinia pseudoacacia and a Max, Hybrid 275, Koreana, Willow: Tora, Inger, Tordis). collection of flowering shrubs) were interspersed between the Max clones (Fig. 1) to increase ecological (a) significance. Costs and benefits of all test parameter are analysed. Between the SRC strips a conventional crop rotation consisting of winter wheat, spring barely and winter rape is cultivated. ;:::: .;.:: (b) ~~i~1:~:~~ ,~.::i:".:~,~,·,!:~:.~:!,:..:~l;;~;l~ :..,.::.:I..:..: ....:•..:::....:::.• ...... :.;[~~~;:.~ :~.:".~:~:~~.:.;~~::.:~.<:~.~~:,.:·.::.':.,~ :~.:.:.::::::::i: '(~t:'tM .: .. ... ...... :.:·.. ..... ~ r:",.~: ........ JKl .......J,8 ~ . Figure 1: Experimental design of the large-scale agroforestry system in Thuringia 2.2 Recultivation area, Brandenburg State, Germany The post-mining landscape in the Lusatian lignite mining district, located in the Southem Brandenburg State (approx. 150 km south from Berlin, Germany) is characterized by low precipitation and marginal soils. Due to these conditions crop yield is low, and hence, conventional land use systems often fail in terms of a reliable and efficient crop production. The production of short rotation woody biomass in alley cropping systems for bioenergy may be a promising alternative to improve Figure 2: Experimental design of the agroforestry soil fertility and to enhance the economical value ofthese systems in Lower Saxony with uniform tree species (a), post-mining areas. A central question at this site is with inclusion of aspen trees (b) and with inclusion