Title: An extreme value analysis of top performing UK winter wheat producers
Authors: Emily Mitchell - The University of Nottingham (United Kingdom) [presenting]
Gilles Stupfler - ENSAI - CREST (France)
Andrew Wood - The University of Nottingham (United Kingdom)
Neil Crout - The University of Nottingham (United Kingdom)
Paul Wilson - The University of Nottingham (United Kingdom)
Abstract: Using the responses to a UK-based survey, we present the first application of extreme value theory in an agricultural setting to complement the previous studies conducted from a classical central perspective in this field. The Farm Business Survey collects a substantial amount of information annually from farms across England and Wales with the purpose of providing farmers with an overview of farming performances. Winter wheat is the most popular crop grown in the UK due to its optimal growing conditions; therefore, we focus on winter wheat production from 2006 to 2015 and extract a subset of variables from this data set, among which the obtained yield and net margin, and apply a number of established extreme value analysis methods. In particular, we use a mix of Peaks-Over-Threshold and semi-parametric approaches to fit distributions to the tail before ultimately producing extreme quantile estimates. We conclude by stratifying about pesticide usage for top UK winter wheat producers to address the inconsistencies of management practices; moreover, we compare quantile estimates between stratum and discuss the implications of our results.