Applying plant ecological knowledge to increase agricultural sustainability

1. Plant ecological knowledge accumulated over the past 150 years has enormous implications for agriculture, but most of these implications have not been appreciated by ecologists or agronomists. Here, I present several of the most salient examples. 2. Agriculturalists refer to 'improvements', but plant ecologists know that 'trade-offs' represent a better conceptual framework for agricultural production. There is much evidence for trade-offs between yield and resource use efficiency, and between individual fitness and population yield. I argue that there is also a 'limiting trade-off' between short-term yield and sustainability, and it is important to take this into consideration if we are serious about increasing sustainability. 3. At the local level, agricultural sustainability is about maintaining or improving soil fertility, but this is not a priority in most agricultural systems world-wide. Increased biomass density (both living and dead) in the field is the key to increasing sustainability while maintaining high yields, and I present a vision of 'High Biomass Cropping Systems'. 4. Classical and current research in plant community ecology tells us that rotation of crops with different nutritional needs, pests, diseases and weeds can make a major contribution to sustainability. The very limited crop rotations practised in most modern plant production systems are a clear indication that farming practices are usually based on short-term economic and regulatory factors, without much if any consideration for sustainability. 5. Synthesis. The modern scientific method tells us how we should test hypotheses, but it says nothing about how hypotheses are generated. We need to address the agricultural research agenda if it is to serve the interests of farmers, consumers and society as a whole, rather than narrow but powerful economic interests.