Results identify cropping system, area under cultivation, consumption requirements and crop prices as important determinants of sustainability.
This would require massive deforestation around the world, and conversion of many fragile hillsides and drylands to cropping for which they are environmentally unsuitable.
As a result, they cannot consider the impact of cropping activities on the natural processes that support fertility recovery.
Through the 1970s and 1980s, a cropping/far ming systems approach was added to the research agenda, including research on optimum rotations and cover crops.
In this case single cropping was the lowest, relay cropping intermediate and double cropping the highest in seed oil concentration.
Blends and component cultivars had similar net returns under all cropping systems tested.
The average of cropping systems demonstrated the same pattern of net return.
The economic analysis was based on estimates of the costs and returns of each cropping system.
