The difficulty of planting kalinayan and other rice varieties with the soil type in these areas leads to the building of the rice terraces entailing construction of retaining walls with stones and rammed earth which are designed to draw water from a main irrigation canal above the terrace clusters. Indigenous rice terracing technologies have been identified with the Ifugao’s rice terraces such as their knowledge of water irrigation, stonework, earthwork and terrace maintenance. As their source of life and art, the rice terraces have sustained and shaped the lives of the community members. Organic farming In March 2009 the Ifugao rice terraces were declared free from genetically modified organisms (GMO). An event declaring this achievement was organized in Dianara Viewpoint in collaboration with local and municipal government, Greenpeace, and the Miss Earth Foundation. Official heritage designation The Banaue Rice Terraces refer to the cluster close to the Banaue poblacion as seen from the viewpoint. Contrary to popular belief perpetrated by its inclusion on the twenty peso banknote, the Banaue Rice Terraces are not a UNESCO World Heritage Site. They were not included in the UNESCO inscription Rice Terraces of the Philippine Cordilleras due to the presence of numerous modern structures, making it score low in the integrity criterion of UNESCO. The five clusters inscribed as part of the Rice Terraces of the Philippine Cordilleras are Batad, Bangaan, Hungduan, Mayoyao Central and Nagacadan. Batad and Bangaan are under the jurisdiction of the Municipality of Banaue but are not called the Banaue Rice Terraces. The Banaue Rice Terraces were declared by the Philippine government as a National Cultural Treasure under Ifugao Rice Terraces by virtue of Presidential Decree No. 260 in 1973. Tourism Another thriving economy in the Banaue Rice Terraces is tourism. The Tourism industry has developed a number of activities for visitors which may include traditional sightseeing of the terraces and visits to the tribes at the foot of the terraces. A Mumbaki (traditional Ifugao witch doctor) is also recommended to visitors: these doctors can perform spiritual healing rituals. Domestic tourism however has gone down over the past few years. A contributing factor to this is the treatment of domestic tourists by the local guides in the area where it has been reported that local guides are more willing to entertain foreign visitors. The Batad Environmental Tour Guides Association (BETGA) in association with the Batad Baranguay authorities are currently laying