Relationships among Mineralizable Soil Nitrogen, Soil Properties, and Climatic Indices
- Jacynthe Dessureault-Rompréa,
- Bernie J. Zebarth *a,
- David L. Burtonb,
- Mehdi Sharifib,
- Julia Cooperc,
- Cynthia A. Grantd and
- Craig F. Drurye
- a Agriculture and Agri-Food Canada, Potato Research Centre, PO Box 20280, Fredericton, NB, Canada E3B 4Z7
b Dep. of Environmental Science, Nova Scotia Agricultural College, PO Box 550, 21 Cox Rd., Truro, NS, Canada B2N 5E3
c Nafferton Ecological Farming Group, Newcastle Univ., Nafferton Farm, Stocksfield, Northumberland NE43, 7XD, UK
d Agriculture and Agri-Food Canada, Brandon Research Centre, Grand Valley Rd., Brandon, MB, Canada R7A 5Y3
e Agriculture and Agri-Food Canada, Greenhouse and Processing Crop, Research Centre, Harrow, ON, Canada N0R 1G0
Soil N mineralization is an important N contributor to crop uptake; however, the soil and climatic controls on soil mineralizable N are poorly understood. Soil samples from 56 sites across Canada were used to determine the potential to predict the size of mineralizable N pools through simple soil properties and through simple climatic indices and the re_clim indices. Mineralizable N was determined using a 24-wk aerobic incubation at 25°C. Potentially mineralizable N (N0) was estimated by curve fitting using N mineralized from 2 to 24 wk, and Pool I, a labile mineralizable N pool, was determined as the N mineralized in the first 2-wk period. Soil properties were relatively effective predictors of N0 with soil organic N (SON) and sand explaining 40 and 34% of the variability, respectively. Particulate organic matter N (POM-N) and pH explained 18 and 25%, respectively, of the variability in Pool I. Simple climate normals were generally poor predictors of pool size except for potential evapotranspiration (PET), which predicted 24% of the variability in Pool I. The re_clim indices, normally applied to the activity of soil decomposers and applied here for the first time to explain soil mineralizable N pool size variability, performed better than simple climate indices and explained up to 26% of the variation in N0 By including soil and climatic parameters in a multiple regression model, it was possible to explain about 63 and 40% of the variability in N0 and Pool I, respectively, across a wide range of arable soils in Canada.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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