Conservation Agriculture With Trees, a form of Agroforestry - an institutional perspective

Historically agriculture in many parts of the world was compatible with the retention
of valuable trees in cropped fields. It used only superficial soil tillage, usually in
combination with a controlled fire that cleared the land but did not kill the larger trees1
. In temperate zones with relatively mild climates, however, a different approach to
growing crops emerged, “non-conservation agriculture without trees”, which had
success as it was readily scaled up with horse-drawn ploughs replacing human
tillage, and tractors with ever-more horse power drawing ever-deeper ploughs
through a soil that responded by mineralizing a substantial part of its organic matter,
feeding the crops. This yield benefit, however, was not sustainable as it depleted
the resource base – chemical fertilizer had to become the basis ofplant nutrition.
As tillage had killed many of the worms and other minute soil engineers, tillage
became “necessary” to create a structure compatible with crop roots. The trouble
started when this tree-less tillage-addicted form of agriculture became the norm,
became known and taught worldwide as what agriculture is and should be, and was
extended to parts of the world with less benign climates.