The agricultural industry has always been the economic core of Christchurch.  Its surrounding farming countryside has long been the basis of its industry, part of the original "package" sold to New Zealand immigrants. PGG Wrightson, New Zealand's leading agribusiness, is based in Christchurch.  Its local roots go back to Pyne Gould Guinness, an old stock and station agency serving the South Island.  Other agribusinesses in Christchurch have included malting, seed development and dressing, wool and meat processing, and small biotechnology operations using by-products from meat works.  Dairying has grown strongly in the surrounding areas with high world prices for milk products and the use of irrigation to lift grass growth on dry land. With its higher labour use this has helped stop declines in rural population. Many cropping and sheep farms have been converted to dairying. Conversions have been by agribusiness companies as well as by farmers, many of whom have moved south from North Island dairying strongholds such as Taranaki and the Waikato.