Effect of irrigation and grazing animals on soil quality measurements in the North Otago Rolling Downlands of New Zealand

Autor: D. J. Houlbrooke, R. J. Paton, Roger P. Littlejohn, J. D. Morton
Rok vydání: 2008
Předmět:
Zdroj: Soil Use and Management. 24:416-423
ISSN: 1475-2743
0266-0032
DOI: 10.1111/j.1475-2743.2008.00183.x
Popis: The North Otago Rolling Downlands (NORD) of New Zealand is currently undergoing a large change in land use with subsequent intensification as a result of a new large community irrigation scheme. To assess the effect of this change, a 4-year monitoring survey was established on two common Pallic soil types of the area to determine the influence of irrigation term (short, 5 years) and grazing animal (cattle vs. sheep) on a range of physical and organic matter soil quality parameters. This 4-year survey also included the historical land use of dryland sheep farming in the absence of irrigation water. Irrigation term had no significant (P > 0.05) effect on soil physical parameters (percentage macroporosity and bulk density) for 3 of 4 years and no significant effect (P > 0.05) on topsoil total carbon or nitrogen contents. However, irrigation term had a significant (P < 0.01) but biologically small effect on the ratio of carbon to nitrogen with narrowing of the range under longer term irrigation. A significant difference between the dryland and irrigated surveys was found for macroporosity (dryland sheep 17.3% v/v vs. irrigated sheep 13.4% v/v; P < 0.001) and for the C:N ratio (dryland sheep 10.7 vs. irrigated sheep 10.2; P < 0.05). The change in macroporosity under irrigation is likely to take effect within 1 or 2 years of land-use change as little discernable differences in soil physical properties were evident from land under short- or long-term irrigation.
Databáze: OpenAIRE
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