The effect of controlled drainage (CD) on ammonia volatilization (AV) losses from paddy fields under controlled irrigation (CI) was investigated by managing water table control levels using a lysimeter. Three drainage treatments were implemented, namely, controlled water table depth 1 (CWT1), controlled water table depth 2 (CWT2), and controlled water table depth 3 (CWT3). As the water table co...

the management of water table is introduced as one of the major parts of the solutions in water resources management. this method could play a significant role in protecting water resources, increasing irrigation efficiency, preserving nutrients in soil, and protecting the quality of surface downstream, and as well, of groundwater. towards this end, a laboratory study has been done on the effec...

Sand coverings account for a large part of the cost of a project. The purpose of this study is to evaluate the performance of different coatings for filtration of underground drains and reduce the cost of cornfield farms. The experiments were carried out in farm in Salman Farsi. The subsoil drainage was fitted to each test piece with a length of 120 meters, a diameter of 100 mm, and a distance ...

the dominant traditional view to designing drainage systems explains drainage goals only in terms of crop yield increase and rhizosphere improvement while ignoring the environmental impacts of drainage projects. nowadays, this view has been changed into a new one in which both environmental and agricultural purposes are taken into consideration. depth and spacing of subsoil drains are important...

Described by Jean Chevaillier in 1967, autogenic drainage is an airway clearance technique that is widely used throughout Europe. The echnique is characterised by breathing control, where the individual adjusts the rate, depth and location of respiration in order to clear the hest of secretions independently. This paper describes the technique, based on the work of Chevaillier, offering a physi...

subsurface drainage systems are used to control the depth of the water table and to reduce or prevent soil salinity. water flow in these systems is described by the boussinesq equation, and the advection-dispersion equation coupled with the boussinesq equation is used to study the solute transport. the objective of this study was to propose a finite difference solution of the advection-dispersi...