Conventional, Organic and Conservation Agriculture: Production and Environmental Impact

Abstract

Agriculture production has to increase by 70% within 2050 in order to keep pace with population growth and changing diets. However, this production increase will have to be achieved in a way that preserves the environment and reduces the vulnerability of agriculture to climate change. Agriculture will further-more need to minimize the emissions of greenhouse gases, pesticides and plant nutrients like nitrogen and phosphorous to the environment. Organic agriculture, conventional agriculture and conservation agriculture can be considered as different approaches for dealing with these production and environmental challenges. This chapter discusses the production and environmental implications of these three diffe-rent approaches for agricultural development. Conventional agriculture is characterised by ploughing and limited recycling of organic materials. Organic agriculture uses no pesticides and mineral fertiliser whereas conservation agriculture is characterized by zero tillage, use of mulch and crop rotations. The studies reviewed show that conventional agriculture and conservation agri-culture have similar yield levels, but the yield levels in organic agriculture is in the order of 30–50% lower than in these two systems. One important reason for lower productivity in organic agriculture is limited supply of plant nutrients as organic sources of plant nutrients only supply 30–35% of the nitrogen taken up by crops. Conservation agriculture is furthermore more efficient in building soil organic mat-ter than organic agriculture and conventional agriculture. Conservation agriculture has been found to sequester between 0.1 and 1 t C ha −1 year −1 . Building soil organic matter content can be considered as a cornerstone in adaption to climate as this will increase soil water holding capacity and reduce soil temperature. System studies Jens B. Aune 150 J.B. Aune have shown that nitrogen and greenhouse gas emission are less in conservation agriculture as compared to conventional and organic agriculture. The non-use of pesticides is the major environmental advantages of organic agriculture. It appears from this review that conservation agriculture is the approach that can best deliver on the production and environmental objectives of agriculture.