Long-term yields of oilseed rape and winter wheat in a short rotation alley cropping agroforestry system
Alley cropping agroforestry systems (ACS) are ascribed to have manifold positive ecological effects; nevertheless their application is still limited due to uncertain productivity of the agricultural crop, especially in the tree-crop competition zone. Therefore, this study investigated the variability of oilseed rape and winter wheat yield, respectively, at different distances from the tree strip edge in 2016 and 2017 in an ACS established in 2008 in northern Germany. The ACS consisted of strips of fast-growing poplars alternating with narrow (48 m) and wide (96 m) crop alleys, each with a crop rotation including winter oilseed rape and winter wheat. Each tree strip contained 6 rows of poplars with a density of 10,000 trees per ha. Moreover, multi-year (2009–2016) crop yield data of oilseed rape and winter wheat in the narrow and wide crop alleys were compared with those of a corresponding non-agroforestry control field. In general, crop yields observed in 2016 and 2017 in the narrow crop alleys at 1 m from the tree strip edges were on average 77% (oilseed rape) and 55% (winter wheat) lower than in the middle of the crop alley. One reason for low yield close to the tree strips might be the leaf litter coverage of the seedlings in autumn. Leaf litter deposition was highest at 1 m on the windward and the leeward side of the tree strips in 2015 and on the leeward side in 2016, respectively. However, the average long-term crop yields of the narrow crop alley, the wide crop alley and the control field did not differ substantially among each other. Although oilseed rape and winter wheat yields were lower close to the tree strips, this yield reduction did not negatively influence the average long-term crop yields of the ACS.
© The Author(s) 2018. This article is published with open access at Springerlink.com and is licensed under the Creative Commons Attribution 4.0 International License - https://creativecommons.org/licenses/by/4.0/ . The Version of Scholarly Record of this Article is published in Agroforestry Systems, 2019, available online at: https://link.springer.com/article/10.1007/s10457-018-0288-5 . Keywords: alley cropping; crop yields; winter wheat; oilseed rape; yield variability; competition zone; long-term-yield; leaf litter; Europe; Germany; poplar.
Swieter, A., Langhof, M., Lamerre, J., & Greef, J. M. (2019). Long-term yields of oilseed rape and winter wheat in a short rotation alley cropping agroforestry system. Agroforestry Systems, 93, 1853–1864. https://doi.org/10.1007/s10457-018-0288-5