Novel sprayable biodegradable polymer membrane to minimise soil evaporation

Sprayable film systems for soil to prevent moisture loss have received increased attention as next generation alternatives to the use of preformed films. In this paper we report on the properties of a novel water dispersible, sprayable biodegradable polymer membrane and results of preliminary pot and field trials using this membrane to minimise soil evaporation. The polymer emulsion contains 40 wt% solid content with particle sizes in the 100-500 micron range and its viscosity is 400±70 mPa.s; it is stable at ambient temperature and can be sprayed using standard farm equipment. The small scale pot trial indicated a 10-50% reduction in soil evaporation across a number of different soils. The field trial, on a Hanwood loam soil showed that the polymer membrane treatment maintained approximately the same crop yield compared to the control, but used 28% less irrigation water. Water use productivity was 0.34 to 0.46 kg/100 L higher in the polymer treatment than in the control treatments, representing a 20-30% increase in water productivity. Refinement of the polymer membrane together with further field testing is ongoing.