Seserman, D.M.

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   Factors of success and failure in the transition into agroforestry264th European Agroforestry Conference  Agroforestry as Sustainable Land Use BENEFITS OF AGROFORESTRY SYSTEMS FOR LAND EQUIVALENT RATIO  CASE STUDIES IN BRANDENBURG AND LOWER SAXONY, GERMANYSeserman DM1*, Veste M1,2, Freese D1, Swieter A3, Langhof M3 (1) Institute of Environmental Sciences, BTU Cottbus Senftenberg, Cottbus, Germany (2) Institute of Botany, University of Hohenheim, Stuttgart-Hohenheim, Germany (3) Institute for Crop an -Institut, Braunschweig, Germany *Corresponding author: seserman@b-tu.de  Abstract Transitioning towards agroforestry demands systematic productivity assessments of such systems under different climatic and edaphic conditions. In this regard, the Land Equivalent Ratio (LER) serves as a valuable productivity indicator of agroforestry since it evaluates yields from growing trees and crops together in comparison to yields from monocultures over the same period. Consequently, our objective was to evaluate the overall productivity of two agroforestry systems in Forst (Brandenburg) and Wendhausen (Lower Saxony) by means of LER. Our approach followed two assumptions: (i) the yields of trees and crops had equal economic importance and (ii) the economic importance was given solely by the annual crop, the yield of trees representing a supplementary profit. The resulted values for LER were consistently above their specific threshold, corroborating the greater efficiency of agroforestry systems rather than monoculture. Additionally, this study highlighted the importance of choosing the appropriate assumptions when calculating the LER.  Keywords: agroforestry; land equivalent ratio; land use efficiency; tree yield; crop yield  Introduction With comparison to conventional agricultural systems, the integration of trees and arable cropson the same land has been increasingly justified by a range of environmental benefits regardingbiodiversity, soil fertility, microclimatic conditions, and overall productivity, and are widely usedas wind protection systems against soil erosion (Slazak et al. 2013; Kanzler et al. 2016).However, considering that agroforestry systems have a planning horizon of several decades,the productivity of such systems needs to be periodically assessed for forthcoming riskassessments and adaptation scenarios in the near future.  In this regard, the Land Equivalent Ratio (LER), defined as the relative yield of each tree andcrop species in an agroforestry system in comparison to the yield of the same tree and cropspecies in a monoculture over the same period (Mead and Wiley 1980), was used as a methodto determine the overall productivity of two agroforestry systems in Forst (Brandenburg) andWendhausen (Lower Saxony).   Objectives Given the fact that land-use systems have different goals, there are different methods ofquantifying the LER in agroforestry systems (Ong and Kho 1996). Therefore, the main objectiveof this study was to evaluate the overall productivity of two agroforestry systems in Forst(Brandenburg) and Wendhausen (Lower Saxony) by means of LER with an emphasis on (i) theyield of both trees and crops (after Mead and Wiley 1980) and (ii) the yield of annual crops (afterOng and Kho 1996) as a principal economical product.    Factors of success and failure in the transition into agroforestry274th European Agroforestry Conference  Agroforestry as Sustainable Land Use Materials and methods Study sites This study was carried out on two agroforestry systems established near Forst (N E 67 m a.s.l.) and Wendhausen   85 m a.s.l.). Theagroforestry system near Forst is based on a dominantly pseudogleysol type of soil with a loamysand texture and has an annual average temperature of  and an average annualprecipitation of 568 mm (DWD Station Cottbus). The agroforestry field near Wendhausen ischaracterized by a pelosol with a silty clay soil texture and has an average annual temperatureof  and an average annual precipitation of 616 mm (DWD Station Braunschweig). The agroforestry system in Forst consists of seven tree strips in a north-south orientation,having a width of 11 m and a total length of 660 m, with agricultural alleys of 96 m, 48 m, and 24m width between the tree strips (Kanzler and  2016). The system in Wendhausen consistsof four tree strips having a width of 12 m and a total length of 50 m, with agricultural alleys of 48m width between the tree strips, as well as a control field with short rotation coppices (SRC)planted on a 70 x 70 m surface (Lamerre et al. 2015). Based on the joint BMBF-Project SIGNAL (Sustainable Intensification of Agriculture throughAgroforestry), four core- (agroforestry) and four reference-plots (monoculture) were establishedon these experimental sites in 2015. Two windward and two leeward core plots were set on the48 m agricultural alleys and included the first two rows of trees. The planting density was ofabout 8,700 trees per hectare (1.3 m by 0.9 m within the rows) and 10,000 trees per hectare (2m by 0.5 m within the rows) for Forst and Wendhausen, respectively (Kanzler and  2016;Lamerre et al. 2015). Yield assessment Regarding the tree yield, first rotation hybrid poplars (Populus nigra L. x P. maximowicii Henry,clone   were harvested at the end of vegetation period 2014 and 2013 in Forst andWendhausen, respectively. In the second rotation, annual measurements of breast heightdiameter (BHD) were taken in winter 2015/2016 and 2016/2017. According to these diametermeasurements, 25 shoots were chosen, manually cut 10 cm above the ground, chipped andweighted. An allometric equation of the form M = a D b was used in order to derive the drymatter of all measured diameters, where M is the tree biomass (kg), D is the shoot basaldiameter (cm) and a and b are the intercept and slope of a least-square linear regression of ln-transformed data. The yearly tree woody biomass production per hectare was estimated foreach core plot using the average number of shoots per hectare and the average dry mass of theshoots, according to the mean stool method (Lamerre et al. 2015). Regarding the crop yield, winter wheat (Triticum aestivum L.) was harvested in 2016 and winterbarley (Hordeum vulgare L.) was harvested in 2017 in Forst, whereas in Wendhausen winterrapeseed (Brassica napus L.) was harvested in 2016 and winter wheat in 2017. Due to the factthat different crops were grown at the agroforestry systems in Forst and Wendhausen, we useda normalized crop unit (GE;  in order to calculate and compare the agriculturalproduction per hectare. Accordingly, 1 dt wheat corresponded to 1.04 GE, 1 dt barley to 1.00GE, and 1 dt rapeseed to 1.30 GE (Schulze  and Klapp 2010).   Regarding the monoculture systems, we distinguished between the reference crop plot as theagricultural system and the reference tree plot as the SRC. Lacking an identical plantingscheme of trees between the agroforestry systems and SRC, we assumed that the annualbiomass increments of the inner rows of the agroforestry system are comparable to those in theSRC. Thus, in Forst, measurements were collected from four double-row plots with poplar treesand we assumed the inner two rows as similar to an SRC. In Wendhausen, measurements werecollected from the SRC planted on the control field. Land equivalent ratio The land equivalent ratio (LER) is the ratio between the relative yield of each tree and cropspecies in an agroforestry system in comparison to the yield of the same tree and crop speciesin a monoculture over the same period.     Factors of success and failure in the transition into agroforestry284th European Agroforestry Conference  Agroforestry as Sustainable Land Use Firstly, we calculated the LER for each system under the assumption that the yields of trees andcrops are of equal economic importance, after Mead and Wiley (1980):        (Eq. 1)While LER1  1 means that there is no productivity advantage of agroforestry over monoculture,a LER1 > 1 suggests that the production in the agroforestry system is higher than the one in amonoculture system.  Secondly, we calculated the LER for each system under the assumption that the economicimportance is given solely by the annual crop, as the yield of trees is generally regarded as asupplementary profit. Consequently, the difference in crop yield resulting from the presence oftrees relative to the yield of the sole crop was determined according to Ong and Kho (1996):       (Eq. 2)  In this case, LER2 > 0 suggests that the production in the agroforestry system is higher than theone in a monoculture system.  Results and discussion The land equivalent ratios show considerable differences between the two agroforestry sitesover the investigated two years (Figure 1). Figure 1: The land equivalent ratio with regard to the variation of data calculated for the agroforestry systems in Forst and Wendhausen after Mead and Wiley 1980  LER1 (a) and after Ong and Kho 1996  LER2 (b). The grey line serves as a threshold above which the agroforestry system has greater productivity than the monoculture system. All of the obtained values for LER were consistently higher than their specific threshold, meaning that in both cases and for both locations, the agroforestry system had a greater productivity than the monoculture system. Regarding the LER calculations according to Mead and Wiley (1980), the agroforestry systems in Forst and Wendhausen achieved values between 2.0 and 2.9, respectively. Relatively lower results were reported by van der Werf et al. (2007) and Graves et al. (2007), with an LER value between 1.0 and 1.8, as calculated after Mead and Wiley (1980).    Factors of success and failure in the transition into agroforestry294th European Agroforestry Conference  Agroforestry as Sustainable Land Use Mentionable would also be the fact that changing the purpose of land-use, i.e. the method of calculating the LER can lead to contradictory conclusions. For example, in 2016, Wendhausen was the more productive field according to LER1, whereas both sites showed similar productivity according to LER2.  Conclusion Our results corroborate the greater efficiency of land use, i.e. greater land equivalent ratioswhen trees were integrated with arable crops rather than grown as sole crops and highlight theimportance of choosing the appropriate method when calculating the land equivalent ratio.  Acknowledgements We are grateful to our colleagues at the Chair of Soil Protection and Recultivation, BTU Cottbus Senftenberg, and the Julius -Institut in Braunschweig, for their support and scientificcollaboration. Additionally, we thank the Agrargenossenschaft Forst/L. e.G. for their promotionand management of the agroforestry systems at Forst. The research was carried out under theBonaRes - SIGNAL project (FKZ 031A562E, 2015-2018) and funded by BMBF - GermanFederal Ministry of Education and Research (Bundesministerium  Bildung und Forschung). References Graves AR, Burgess PJ, Palma JHN, Herzog F, Moreno G, Bertomeu M, Dupraz C, Liagre F, Keesman K, van der Werf W, Koeffeman de Nooy A, van den Briel JP (2007) Development and application of bio-economic modelling to compare silvoarable, arable, and forestry systems in three European countries. Ecol Eng 29: 434 449. (AgroForstEnergie II): - tz und Rekultivierung, Cottbus. rck J, Schmitt D, Veste M (2016) Agroforstliche Landnutzung als Anpassungsstrategie an den 127. Lamerre J, Langhof M, Sevke-  JM, Dauber J, Hirschberg F, Joormann I, Krestel N, Masur D, Reith C (2016) Nachhaltige Erzeugung von Energieholz in -Institut Bundesfor - Bodenkunde, Braunschweig. Mead R and Willey RW (1980) The concept of a "Land Equivalent Ratio" and advantages in yields from intercropping. Exp Agr 16: 217 228. Ong CK and Kho RM (1996) A framework for quantifying the various effects of tree-crop interactions. In: Ong CK and Huxley P (eds) Tree crop interactions: a physiological approach. CAB International, Wallingford, pp 1 23.reide- -August- - Forschungs- - : Wagener F, Heck Schlussbericht, ELKE III, Hochschule Trier, Umwelt-Campus Birkenfeld, pp 130 149. Van der Werf W, Keesman K, Burgess PJ, Graves AR, Pilbeam D, Incoll LD, Metselaar K, Mayus M, Stappers R, van Keulen H, Palma J, Dupraz C (2007) Yield-SAFE: A parameter-sparse, process-based dynamic model for predicting resource capture, growth, and production in agroforestry systems. Ecol Eng 29: 419 433.    

Benefits of agroforestry systems for land equivalent ratio - case studies in Brandenburg and Lower Saxony, Germany

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Benefits of agroforestry systems for land equivalent ratio - case studies in Brandenburg and Lower Saxony, Germany

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