Poplar leaf biomass distribution and nitrogen dynamics in a poplar-barley intercropped system in southern Ontario, Canada |
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Authors: | N V Thevathasan A M Gordon |
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Institution: | (1) Agroforestry, Department of Environmental Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada |
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Abstract: | The effect of hybrid poplar (Populus spp. clone DN 177) leaf biomass distribution on soil nitrification was investigated in two experiments during the 1993, 1994
and 1995 growing seasons in a poplar-barley (Hordeum vulgare cv. OAC Kippen) intercropping experiment established at Guelph, Ontario, Canada. In experiment 1, poplar was intercropped
with barley during all three years and the poplar leaves shed during the fall season were removed from the soil surface during
1993 and 1994. In experiment 2, poplar was intercropped with barley in 1993 and with corn (Zea mays cv. Pioneer 3917) in 1994 an 1995, respectively, and the shed poplar leaves were not removed. In experiment 1, the nitrification
rates were lower during 1994 and 1995 when the dropped leaves were removed from the field. The total above-ground biomass
of barley within 2.5 m of the tree row was 517, 500 and 450 g×m−2, respectively during the three years, whereas in the middle of the crop row (4–11 m), the corresponding figures were 491,
484 and 464 g×m–2. Mean nitrification rates, N availability and carbon content were higher in soils close to the poplar tree
rows (2.5 m) compared to the corresponding values in the middle of the crop alley (4–11 m from the tree row). In experiment
2, where poplar leaves were not removed from the field, nitrification rates in soils within 2.5 m distance from the poplar
row were fairly constant (range 100 to 128 μg 100 g−1 dry soil day−1) during the three years. Results suggest that soil nitrification rates, soil carbon content and plant N uptake adjacent to
the poplar tree rows are influenced by poplar leaf biomass input in the preceding year.
This revised version was published online in June 2006 with corrections to the Cover Date. |
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Keywords: | interactions intercropping nitrogen mineralization |
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