Influence of long-term tillage, straw and N fertilizer on barley yield, plant-N uptake and soil-N balance |
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Authors: | M. Nyborg E. D. Solberg R. C. Izaurralde S. S. Malhi M. Molina-Ayala |
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Affiliation: | a Department of Renewable Resources, University of Alberta, Edmonton, Alta., Canada T6G 2E3 b Soils and Crops Branch, Alberta Agriculture, Food and Rural Development, Edmonton, Alta., Canada T6H 5T6 c Agriculture and Agri-Food Canada, Lacombe, Alta., Canada T0C 1S0 |
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Abstract: | Long-term influence of N fertilizer, tillage and straw on crop production and soil properties are not well known in central Alberta. Field experiments were established in autumn 1979, on a Black Chernozemic soil and on a Gray Luvisolic soil in north-central Alberta to determine the long-term effect of tillage, straw and N fertilizer on yield and N uptake of barley (Hordeum vulgare L.). Fertilizer N was applied annually at 56 kg ha−1. The 11 year averages of barley yields and N uptake under zero tillage were lower than under conventional tillage. Retention rather than removal of straw tended to reduce barley yield for the initial 6 years and 2 year at Site 1 and Site 2, respectively. A simple mathematical model of average annual plant N uptake and grain yield could account for most of the variation in the data observed at both sites (R2 = 0.907; P < 0.01). Final values of soil N, calculated using a mass balance approach, agree closely with values measured at the end of the eleventh year. Conventional tillage and zero tillage, with addition of fertilizer N and retention of straw, were the only treatments with apparent but small net addition of N to soil at Site 1 (40 kg ha−1 and 117 kg ha−1, respectively). At Site 2, only the zero tillage treatment with addition of fertilizer and retention of straw gained soil N (29 kg ha−1). In conclusion, soil ecosystems functioning in subhumid environments with slight to moderate heat limitations such as those in central Alberta can adapt, within a few years, to zero tillage practices with full retention of straw. |
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Keywords: | Author Keywords: denitrification N mineralization-immobilization nitrate leaching soil quality zero tillage |
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