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Land use trends and the influence of orchard management on the soils in Creston, B.C.

University of British Columbia

The effects of apple orchard management on soil morphology and fertility were examined by comparing the soil under native coniferous vegetation with the soil in the orchard. In 50 years, irrigation and fertilization of the grassed orchard soils in Creston, British Columbia has provided a much greater supply of readily decomposable organic litter than the forest had provided in hundreds of years. A Sombric Brunisol has evolved from a Dystric Brunisol in the sandy glaciofluvial material of the Elmo soil series and a Dark Gray Luvisol has developed in the site originally occupied by the Lister soil series Orthic Gray Luvisol. Through orchard management, total carbon, total nitrogen and extractable phosphorus were enhanced in the surface soil of both orchard sites. The greater amount of organic matter and extractable phosphorus in the Elmo soil orchard site was the major feature distinguishing the orchard from the forest site. Within the orchard site a concentration of cations at the surface and a depletion between 30 and 60 cm characterized the soil inside the orchard dripline. In general, samples collected within the dripline of the sandy orchard soil represented a different population than samples collected outside the dripline. In addition to more carbon, nitrogen and extractable phosphorus, a greater level of exchangeable bases was found at most sample depths in the Lister soil orchard site. This was foreshadowed by field observations indicating that up to 10 centimeters of surface soil had been eroded or removed from the orchard soil, thereby reducing the depth to the calcareous parent material. In contrast to the differences observed across the dripline in the sandy soil, little or no difference in soil chemical properties was noted across the dripline in the heavier textured Lister soil series. Since Creston represents one of the very few areas in Canada capable of producing tree fruits the changes that have taken place since 1950 in land use and orchard productivity were investigated. By diminishing the tonnage of fruit produced, the loss of orchard land to subdivisions prior to 1972 poses a threat to the continuation of a viable fruit industry. However, an uncertain market and low returns to the growers appear to play a greater role in land use allocation in Creston than does urban encroachment. A drop in total apple production in Creston since 1950 was credited to the loss of 190 hectares of orchard land. Through better space utilization and earlier bearing, new semi-dwarf tree plantings that are beginning to produce fruit will aid in surpassing the 1950 production value.

Text

2010-05-15

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http://hdl.handle.net/2429/24736

Soil Science

University of British Columbia

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