Nitrogen fertilization of poplar plantations on agricultural land: effects on diameter increments and leaching |
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| Authors: | Ioannis Dimitriou Blas Mola-Yudego |
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| Institution: | 1. Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), Uppsala, Swedenioannis.dimitriou@slu.se;3. School of Forest Sciences, University of Eastern Finland (UEF), Joensuu, Finland;4. Norwegian Institute of Bioeconomy Research (NIBIO), ?s, Norway |
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| Abstract: | Fast-growing poplar plantations on agricultural land require intensive management activities, often involving fertilization. The present paper aims at investigating the effect of fertilization on growth and on groundwater quality, by examining four trials established in commercial poplar plantations in central and south Sweden. The treatments consisted of nitrogen applications (Urea N46, Tot. N: 46%) in two different dosages, 75 and 150?kg?ha?1 for two years, and a control, in three replicates (plot size: 20?×?20?m) following a randomized block design. Diameters were measured at each plot at the end of each growing season for the period 2012–2015. At the same time, groundwater pipes were installed in the center of each plot, at ca. 1.5?m depth. Samples were regularly collected and analyzed for NO3-N and PO4-P. The results show a large variation in the diameter growth response to nitrogen fertilization and the leaching of poplar plantations after canopy closure. In young plantations, the effect on growth was clear with moderate fertilization rates although it was not observed on sandy soils with already good growth, leading to high nitrogen leaching. |
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| Keywords: | Poplar plantations groundwater fertilization nutrient runoff fast-growing plantations Populus spp |
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