Decades of weather data could support better farm planning

// Farm Planning

Twenty-five years of weather data from a central Otago farm is being analysed to see if it could help farmers plan better around temperature and moisture variations across different altitudes and aspects.

weather station at Mt Grand

The pilot programme, led by Professor Derrick Moot of Lincoln University, is one of multiple work strands underway as part of the Hill Country Futures Partnership, a five-year project co-funded by Beef + Lamb New Zealand, the Ministry of Business, Innovation and Employment, PGG Wrightson Seeds and Seed Force New Zealand.

The $8.1m programme is focused on future proofing the profitability, sustainability and wellbeing of New Zealand’s hill country farmers, their farm systems, the environment and rural communities. It differs from most pastoral-based research in that it considers the whole-farm system and, critically, the wider communities these systems exist within.

Professor Moot said the decades of data from Lincoln’s Mt Grand station, near Lake Hāwea, will be compared to that from NIWA’s Virtual Climate Network.

“Lincoln has had weather stations at Mt Grand for 25 years, recording temperature and rainfall at three different altitudes. It is easy to predict what is happening on flat land but most of New Zealand is hill country and there is lots of local change, through aspect and altitude or north or south facing slopes.

“NIWA gets its information from weather stations but also has a virtual network with the climate for the whole of New Zealand. What we want to see is how well the predictions from that match the data from our weather stations.

“Stations at the bottom of the valley do not pick up the difference between sunny and shady slopes so we are trying to quantify the difference in temperature and moisture across different altitudes and aspects and ultimately to help farmers plan better.”

NIWA’s Virtual Climate Station Network (VCSN) data are estimates of rainfall, air and vapour pressure, relative humidity, solar radiator, wind speed, soil moisture and evapotranspiration – the processes by which water moves from the Earth’s surface into the atmosphere. These are set out on a regular 5km grid covering the whole of New Zealand. The estimates are produced daily based on spatial analysis of data observations from NIWA’s nationwide network of climate stations.

“We are looking to see how big the difference is and how much of a difference it makes, and whether we could use NIWA’s virtual network,” says Professor Moot. “This is just a pilot, not a solution, but we have the opportunity to do this with the dataset we have available.”

Many of the Hill Country Futures Partnership programmes overlap and complement one another and Professor Moot said the Mt Grand data pilot will feed into research being led by Dr Nathan Odgers of Manaaki Whenua Landcare Research, to map micro-indicators – soil temperature and moisture – in the hill country landscape and use this data to support and link to the forage models being developed in other parts of the programme.

As hill country farms typically have diverse landscapes within individual farms, there is a need to help farmers quantify key soil and terrain features of these landscapes, such as soil temperature and moisture dynamics. This work will enable robust decision-making for farmers around the most suitable locations and potential benefits of introducing forage legumes into their hill country landscapes. Data acquisition of micro-indicators from six farm test sites is ongoing and is being monitored in near real time.