Winter forage cropping and grazing practices in New Zealand hill country can result in severe de-vegetation and erosion, and therefore have a significant negative impact on downstream water quality. Research has shown that sediment and nutrient losses from winter-grazed hill country pasture are greater with increased slope and increased percentage of bare ground associated with soil damage from treading.
The Ministry for the Environment (MfE), as part of the Essential Freshwater policy development process, engaged Manaaki Whenua – Landcare Research (MWLR) to assess the spatial extent of hill country forage cropping and intensive grazing, as well as the severity and timing of de-vegetation that results from these practices. The work, as part of the Advanced Remote Sensing Aotearoa (ARSA) programme, used recently developed methods for automated cloud clearing to temporally analyse Sentinel 2 imagery for the period autumn to spring 2018, and to identify all paddocks with a slope of 7 degrees or greater where winter forage paddocks became bare due to cattle grazing.
Manaaki Whenua researchers involved: Stella Belliss, David Pairman, John Dymond, Alexander Amies, Jan Zoerner, James Shepherd, John Drewry