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Gewählte Publikation:

Mehdi, B; Madramootoo, CA.
(1999): Soil nitrate distribution under grain and silage corn using three tillage practices on a loamy sand in southwestern Quebec
SOIL TILL RES. 1999; 51(1-2): 81-90. FullText FullText_BOKU

Nitrate leaching is a significant non-point pollution source in intensive agriculture. Appropriate agronomic management practices which reduce nitrate leaching need to be investigated. A two-year field study was conducted in southwestern Quebec on a 2.3 ha site of Typic Endoaquent planted to corn (Zen mays L.). Three types of tillage practices [conventional tillage (CT), reduced tillage (RT), and no-till (NT)] were combined with two residue levels [with (+R) and without (-R)] in a randomized complete block design. The effects of residue, tillage, depth and wheel tracks were examined on soil NO3--N distribution. Soil samples were collected at nine sampling times between November 1995 to November 1997, from 0-15, 15-25, and 25-50 cm depth, except in July and August of 1996, where samples were collected from 0-10, 10-20 and 20-30 cm depth. In spring and fall, a tractor-borne hydraulic auger was used to sample the soil. During the growing season soil cylinders and T-samplers were used. Soil samples taken a few weeks after the application of fertilizer had highly variable NO3--N concentrations in the surface layers (2.5-311.5 kg NO3--N ha(-1)), whereas samples obtained before fertilizer application, in spring, ranged from 7.3 to 11.3 kg NO3--N ha(-1), and fall samples ranged from 4.5 to 13.1 kg NO3--N ha(-1). In spring and fall, NO3--N was higher at 25-50 cm than at 0-15 cm, which may have been an indication of leaching during the non-growing season. July and August samples had less NO3--N at lower depths compared to the spring and fall, despite the fact that surface layers in these months had up to 70 times more NO3--N than in spring or fall. In May 1996 residues were found to have a significant effect on decreasing soil NO3--N at 0-15 cm depth in all tillage treatments. In July 1996 wheel tracks were found to have higher NO3--N in CT+R (77.0 kg ha(-1)) and NT+R (39.6 kg ha(-1)), compared to RT+R (13.0 kg ha(-1)). Two weeks later significantly lower NO3--N concentrations were measured in CTS-R (52.7 kg ha(-1)) and NT+R (7.4 kg ha(-1)), but RT+R had slightly higher NO3--N concentrations (20.9 kg ha(-1)). When ammonium nitrate fertilizer was applied, no difference in soil NO3--N concentrations between the treatments was observed. Implementing conservation tillage practices, such as reduced tillage and no-till, and residue management practices were found to be an efficient way of reducing NO3--N levels in the soil profile when urea fertilizer is applied. (C) 1999 Elsevier Science B.V. All rights reserved.
Autor*innen der BOKU Wien:
Mehdi-Schulz Bano
BOKU Gendermonitor:

Find related publications in this database (Keywords)
nitrate distribution
grain corn
silage corn
conventional tillage
reduced tillage
soil profile

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