If its blade is completely inserted into the soil, the field is considered properly irrigated. In a few locations, the irrigated soil is thrown upside down. If it splits into pieces, it is taken as a sign of a well-irrigated field. Since water is transported through earthen channels, it results in huge conveyance and application losses due to seepage. The irrigation efficiency is between 50 to 60 per cent.
Similar losses occur in the case of water stored in dug-out ponds.
Spang grass is called Pang in Ladakh, where it grows profusely. Local people use this grass as an inner lining for water courses and ponds in order to prevent percolation losses. Spang grass has special non-permeable properties similar to that of a polythene sheet or cement lining. Farmers claim that its use in water retention gives far superior results than both polythene and cement. Its mysterious chemistry requires detailed analysis.