MOLE DRAINING

Wairarapa Times-Age, 20 August 1943, Page 6

MOLE DRAINING

IMPROVEMENT OF PASTURES AND CROPS. Soils with a dense clay subsoil which are subject to a fluctuating water table with waterlogging of the topsoil at certain seasons of 'the year are unsuitable for the best growth of pastures and crops, states a bulletin of the Canterbury Chamber of Commerce. Cultivation is hindered, farming programmes upset and stocking of pastures is restricted. Such soils must be drained before their potential productive capacity can be realised. Soilswhich are in this category and are suitable for mole draining can be improved to a remarkable extent. Mole drains are drawn with a mole plough at a depth of 18 to 24 inches usually during late spring on pasture land. An even fall in the mole is necessary and this makes the removal of surface irregularities advisable, especially on land where the fall is slight. The efficiency of a system of moles is dependent upon the maintenance of a regular and limited fall and a preliminary survey of the field is usually advisable. This should be used as a basis foi the design of the whole layout. The mole drain is simply a tunnel drawn in the subsoil clay and its stability is affected by many factors. The life of a system of moles may vary from a few months to many years but an average life is about 5 years. The costs of installation are also variable but an average installation may cost from 10s per acre for the simplest and most straightforward type to £3 or more for very complex systems. On a per acre basis the annual cost of installation and maintenance is low by comparison with alternative methods of drainage.