No till in field crops and breeding: environmental and economic assessments using the direct margin and the Deltameq® and Indigo® indicators

Abstract

To improve the knowledge on Conservation tillage, in 2001 a French Association for the Promotion of Sustainable Agriculture has lead a three years study in association with the Agricultural public economics department in Paris-Grignon of INRA. This study has been financed by the European LIFE project « Project 99/E/308 ». The methodology applied is an economical and environmental analysis of a panel of selected plots in both Traditional Tillage farms (TT = ploughing) and Conservation Tillage farms (CT) in several French agricultural areas. So, agri-ecological (Indigo® method from INRA) and economical indicators (Deltameq® software from Arvalis) are used to estimate the impact of cropping practices. The results of the survey are significant in two French areas (Indre-et-Loire, Côtes-d'Armor) and with several crops (wheat, soya and maize). It shows a great diversity in CT application. At the economical level, CT allows to maintain the yield levels (from - 8 q to + 5 q/ha), to reduce the machinery global costs (from 0,5 /q in Indre-et-Loire to 1,5 /q in Côtes-d'Armor) and the labour time (from 50 min. to 100 min./ha) and are not synonym of an increase of pesticide or weed-killers costs (from - 14 to + 15 /ha). It maintains also the direct margin levels in Indre-et-Loire, and improves it in Côtes-d'Armor. At the environmental level, CT gives a 65 % increase of the soil organic matter indicator by reduction of mineralization and also has a potential to reduce the emissions of greenhouse gases: less fuel consumption (from - 18 to - 30 liters/ha) and weaker global energy expense.