Fukuoka's hill in Iyo, Ehime
From 1938, Fukuoka began to practise and experiment with new techniques on organic citrus orchards and used the observations gained to develop the idea of "Natural Farming". Among other practices, he abandoned pruning an area of citrus trees, which caused the trees to become affected by insects and tangled branches. He stated that the experience taught him the difference between nature and non-intervention.[10][11] His efforts were interrupted by World War II, during which he worked at the Kōchi Prefecture agricultural experiment station on subjects including farming research and food production.