Subak is the water management (irrigation) system for the paddy fields on Bali island, Indonesia.

The subak system was started some time during the 9th century, when political Bali was a patchwork of kingdoms - which gives food for thought on both aspects: the physical feat of creating such a wondrous landscape, and the profound social impact from the cooperation it imposed as a sine qua non between entities such as kingdoms.

But other documents from the same period mention that the system is linked to the Besakih Temple, which suggests that subak predates the 11th century.

This creates brief fallow periods over large areas and deprives pest populations of their habitat, thus considerably reducing their numbers and maintaining these at a sustainable level.

If there is plenty of water at all times, a uniform cropping pattern will produce the highest rice yields by minimizing pest damage.

Their inspiration is based on several different ancient religious traditions, including Shaiva Siddhanta and Samkhyā Hinduism, Vajrayana Buddhism, and Austronesian cosmology.

[14] Concerning the latter, here are listed some of the commons terms for the various levels of practical administration: Indonesia had to import yearly almost a million tons of rice during the 1950s.

The “Green Revolution”, promising higher yields in rice, was therefore very well received: in 1967 the government launched the Bimbingan massal (BIMAS), or “massive guidance” program, which reached Bali in 1971.

[20] In 1988, a study by World Bank officials reported that the use of pesticides had “pervasively polluted the island's soil and water resources.”[12] That same year the Indonesian government at last recognized the crisis and refused to follow the World Bank directives any further; Suharto revoked his own government's directives, the subak system regained its power of decision over the agriculture, farmers went back to coordinated planting and crops began to recover.

[10] The subak system is presently challenged by a number of factors, including: the small size of individual properties that limits the farmers' ability to attain a decent living; the ageing of subak members, with an age average over 40 years-old in 2019; the decreasing quantity of water resources and pollution; the heavy financial burden on the farmers for carrying out subak activities; and the national government promulgating unclear regulations concerning the irrigation, including traditional irrigations.

The status of Heritage City would drastically reduce the conversion of rice fields into other land uses and would be a considerable help in maintining the remaining subak.

In 2008, during the evaluation of the proposition by the World Heritage Committee, the rice terraces of the original Jatiluwih[c] site was vastly expanded; it was renamed "Subak Landscape of Catur Angga Batukaru" and now includes 17 subak gede institutions, 12 customary villages, the two lakes of Tamblingan and Buyan, and forest areas of Batukaru natural reserves across the two districts of Tabanan and Buleleng - all of which are ecologically and culturally connected to the Jatiluwih terrasses.