Risk assessment modelling

Science programme: Sustainable Land Use

The quest for development of sustainable strategies for maintaining and enhancing the value of the natural capital of the soils and waters of our horticultural production systems will be aided by two initiatives:

• The development of measurement and monitoring tools so that we can better observe soil functioning and plant growth.
• The writing of quantitative computer models that can predict plant growth in response to weather, and that can provide risk assessments of the impact of horticultural production not only on the fruit’s traits, but also the soil and water environment.

Over the last decade, our wealth of measurements is providing us with new knowledge on which we can develop comprehensive computer models. The utility of risk assessment models has been greatly aided by developments in information technology, both through new hardware devices and software development and GIS capacities.

We have developed a comprehensive Soil Plant Atmosphere System Model (SPASMO), a computer modelling system that integrates all the factors, such as climate, soil, and water, that affect environmental processes and plant production systems.

HortResearch has used the model since 1996 to promote sustainable practices for land, based on the calculated risk of land use options. Minimising the risk for alternative practices leads to the development of new sustainable production systems.

SPASMO incorporates various databases, such as a 30-year history of weather data, spatial records of soil types, and knowledge of the chemicals used in pesticides and fertilisers. The model takes a whole system approach and is complemented by data gained from observation of local conditions, experiments and modelling.

We are developing GIS capacity so that these risk assessments can be spatially referenced, and precision horticultural practices developed

Key projects include:

• Management of water demands, and assessing the allocation needs for irrigation
• Prediction of nitrate leaching on horticultural land
• Prediction of pesticide contamination of soil
• The GROWSAFE® Calculator for protecting groundwater for agrichemicals
• Models of plant and fruit growth
• Plant nutrition
• GIS referenced models of the risk of disease and pest incursions.

Our SPASMO modelling framework is being coordinated with the modelling schemes of our CRI colleagues in the SLURI initiative.