After the detailed survey of the paddy rice growth state, those farms put mud snails into paddy fields in time, thus raising the weeding effect to the maximum without affecting the growth of paddy rice.

North Phyongan Province took the lead in this organic farming in the country.

Cooperative farms in the province have ensured the number of mud snails according to areas of paddy fields and the requirements of technical rules.

Chairman Kim Jong Il visited a mud snail breeding ground modernly built at the Jangsan Cooperative Farm in Ryongchon County of North Phyongan Province in June Juche 99 (2010) and gave an instruction on introducing the organic farming method, saying the experience of some farms proved that it is a good method conducive to increasing the yield of paddy rice while saving much manpower, agrochemicals and fertilizer.