The last few months has seen us researching and confirming management strategies for our spring tomato crops. A major component is crop protection planning for conventional, regenerative, and hybrid treatments. In a conventional tomato growing system, the 135 day crop typically receives about 15 spray applications, all with several active ingredients. Regenerative principles seek to reduce agrichemical additions. We have been working with the Watties team and industry advisors to prepare a minimum crop protection programme that should provide an acceptable level of risk to the crop, to people, and to the environment and the soil biological community.
Measuring any potential agrichemical impact and comparing systems is a complex task. There are different types of harm to consider i.e., harm to humans, harm to insects, harm to birds, harm to soil life, etc. How do we describe and rank “harsh” or “soft chemistries? Is our proposed regenerative cropping programme “better” than the conventional one?
McCain’s Agronomist, Ben Prebble proposed the Environmental Impact Quotient (EIQ) model to rate and compare programmes. The EIQ formula was developed at Cornell University by Kovach et al., (1992) to inform growers and advisors wanting to make more environmentally friendly crop protection decisions. The model considers a range of effects (Figure 1), which are categorised into three components: 1) Consumer EIQ, 2) Farm Worker EIQ, and 3) Ecological EIQ. The Environmental Impact Quotient EIQ is a weighted numerical score that allows different active ingredient choices to be compared.
An online tool for calculating EIQ is available through Cornell University (Grant, 2020). This tool uses the base product EIQ value to calculate a Field Use EIQ based on the applied rate of each product. Figure 2 provides an example of the calculator for glufosinate-ammonium (Buster).
Note that regardless of selected application area units, the Field Use EIQ is given in acres (Figure 3), so answers need to be multiplied by 2.47 to give Field Use EIQ per hectare. It is the Field EIQ values that can be used to compare options.
We have used the EIQ tool to calculate a ‘Total Field Use EIQ per hectare’ value for our tomato treatments. The proposed Field Use EIQ for the regenerative treatment is about half that of the conventional treatment. Of course, our production plans are subject to change based on seasonal events! Major contributors to a higher EIQ in the conventional treatment are the use of the pre-emergent herbicide Prosulfocarb, more frequent use of the fungicide mancozeb, and the use of copper hydroxide. We planned a regenerative crop protection programme for growing 100 T/ha, but which has a lower impact on the receiving environment, those handling the chemicals on farm, and those consuming the tomatoes.
We used the University of Hertfordshire Pesticide Properties Data Base (PPDB) for additional information on each active ingredient (University of Hertfordshire, 2023). The database provides information on soil degradation, soil mobility and adsorption, ecotoxicity (including harm to earthworms and honeybees), and risk to human health. A traffic light system is used to indicate risk to environment, ecotoxicity and human health Figure 4.
We are pleased we have a more objective way to assess each of our programmes and their components. The EIQ system is the result of three decades of research and modelling by many people in many organisations, who also incorporated decades of accumulated knowledge – it is not something we could have come up with overnight!
References
Grant, J. (2020). Field Environmental Impact Quotient (EIQ) Calculator [New York State Integrated Pest Management Program, Cornell Cooperative Extension, Cornell University.]. Calculator for Field Use EIQ (Environmental Impact Quotient).
Kovach, J., Petzoldt, C., Degni, J., & Tette, J. (1992). A method to measure the environmental impact of pesticides. New York’s Food and Life Sciences Bulletin, 139.
University of Hertfordshire. (2023). PPDB: Pesticides Properties Data Base. PPDB: Pesticide Properties DataBase.