Soil slip erosion as a constraint to hill country pasture production.

Abstract

Sequential aerial photographs were used to identify, date, and measure the area of slip scars of different age in the Wairarapa. The reduction in potential productivity of hillslopes due to erosion was then determined by measuring the pasture growth rates of the different aged slips (and uneroded ground) and integrating these with the proportions of the hillslopes of each age class. Three years of pasture measurements in the Wairarapa hill country showed that although slips revegetated rapidly over the first 20 years to within 70-80% of the uneroded productivity, further recovery was slow. Since native forest removal, the reduction due to erosion in potential pastoral productivity, integrated over whole hillslopes, has reached 18% on these hillslopes. -from Authors