Effects of halving pesticide use on wheat production

Abstract

Pesticides pose serious threats to both human health and the environment. In Europe, farmers are encouraged to reduce their use, and in France a recent environmental policy fixed a target of halving the pesticide use by 2018. Organic and integrated cropping systems have been proposed as possible solutions for reducing pesticide use, but the effect of reducing pesticide use on crop yield remains unclear. Here we use a set of cropping system experiments to quantify the yield losses resulting from a reduction of pesticide use for winter wheat in France. Our estimated yield losses resulting from a 50% reduction in pesticide use ranged from 5 to 13% of the yield obtained with the current pesticide use. At the scale of the whole country, these losses would decrease the French wheat production by about 2 to 3 millions of tons, which represent about 15% of the French wheat export.

Figure 1. Nine yield response curves fitted by quantile regression, for quantile values ranging from 0.1 (lowest curve) to 0.9 (highest curve) with a step of 0.1.

Two different functions were considered; log (A) and quadratic (B). Black points indicate the yield data.

Figure 2. Fitted yield response curves obtained with the stochastic frontier analysis method using the log function (A) and the quadratic function (B).

Dotted lines indicate the 95% confidence intervals of the fitted curves.

Figure 3. Yield losses resulting from a 50% reduction of pesticide use (in red) and from a 100% reduction (zero pesticide, in blue).

Losses were estimated using quantile regression for quantile values ranging from 0.1 to 0.9. Dotted lines indicate 95% confidence intervals.