Bridging the Gaps in the Future Agroclimatic Suitability of Crops in New Zealand

Environmental conditions (i.e., soil and climate constraints) define where and when crops can be grown and produced. However, climate change threatens agriculture productivity by modifying the distribution of temperatures, the hydrological cycle, and the frequency and intensity of extreme events. In New Zealand, agricultural production represents over 80% of the country’s exported goods. Hence, understanding the impacts of climate change on New Zealand agriculture is necessary to better adapt to future climate conditions.

We combined soil data and CMIP6 climate projections from five models and four Shared Socio-economic Pathways (SSPs) to conduct Land Suitability Analysis (LSA) for five crops: apple, cherry, maize, wheat and pasture. We applied a fuzzy-logic approach with crop-specific indicators to compute the agroclimatic suitability of the five crops across New Zealand. The LSA was performed for each climate model separately to estimate the climate-related uncertainty. The agroclimatic suitability corresponds to the means of computations from individual climate models. In addition, the crop water requirements were quantified considering precipitation and evapotranspiration.

The results show how the agroclimatic suitability patterns of crops will change in the future under different climate change scenarios. This allows for identifying where and when the agroclimatic suitability for a given crop is expected to decrease/increase. Moreover, the computed crop water requirement allows for estimating irrigation needs and water use.

While LSAs have been extensively used in New Zealand, there are gaps in previous applications that our work addresses. This research is the first LSA application in New Zealand that uses a consistent methodology across all agricultural sectors allowing for better inter-crop comparisons. Our study also provides estimates of climate-related suitability uncertainties, which are important to consider when exploring future climate conditions given the role of climate variability on agricultural production. Finally, our work estimates crop water requirements which are critical for future water management planning.
Future application of this methodology to other crops (e.g., winegrapes, kiwifruit, avocado, vegetables, nuts…) will extend our knowledge, give a more comprehensive view of climate change impacts on New Zealand’s agriculture landscape, and help develop better climate change adaptation options.