Effect of irrigation on soil physical properties on temperate pastoral farms: a regional New Zealand study

Context Many regions in the world have undergone rapid land use change and intensification of agricultural land, such as through irrigation expansion, upgrading systems, changing grassland, stock, nutrient management practices. With more intensive use, changes to soil properties can occur, compaction water storage. The effects modern sprinkler-irrigated pastoral farming on physical are not well quantified internationally, particularly for temperate climates. Aims This regional study evaluates effect topsoil subsoil, under grazing sprinkler irrigation, across Canterbury, New Zealand. Methods Paired sites were sampled, consisting a spray-irrigated paddock (field) an adjoined part same that was dryland (unirrigated), with other each pair. Key results Under there shift towards greater abundance smaller pores. reflected macroporosity readily available capacity being significantly lower while semi-available unavailable held below permanent wilting point both increased. Conclusions These differences reflect increased irrigated grazed pasture, dairy grazing, consistent findings similar studies. subsoil but showed most confined (30 cm depth). Implications For management, our indicates pasture is significant, farmers potentially having irrigate frequently. Adopting deficit could minimise impacts compaction.