Alley cropping - a promising multifunctional form of land use for reclaimed lignite mine sites in Germany

Presentation

Since the 1920s more than 80.000 ha land were affected by lignite open cast mining activities in the Lusatia region (Eastern Germany). Subsequently, large post-mining landscapes with substrates poor in humus and nutrients evolved in this region. As a result the conventional crop production on those post-mine areas is comparably restricted. Against this background, the increasing demand for woody biomass for bioenergy and thus the cultivation of fast growing trees for woody biomass production could represent a promising option to enhance the productivity of reclaimed mine land. Thus, considerable research were carried out on reclaiming technologies and improving soil quality with different fast growing tree species in the Lusatia lignite region over the past two decades. It has been shown that a sustainable supply of bioenergy wood is possible with black locust (Robinia pseudoacacia L.) trees even under the unfavorable growth conditions in the marginal post mining area. Since this knowledge is mainly based on studies of monocultural plantations (SRC) in 2007 a short rotation alley cropping system (SRACS) was established in the reclaimed lignite mine site “Welzow-Süd” (25 km south of Cottbus). The present study examines the results of seven years of field measurements carried out within this SRACS in terms of three major environmental and economic benefits of agroforestry: 1) biomass production, 2) soil nutrition and 3) wind velocity reduction, which all can significantly contribute to a successful rehabilitation of degraded landscapes.