Preparation, characterisation and field-testing of a biodegradable sodium alginate-based spray mulch

An innovative biodegradable coating that can be sprayed was developed and tested as suitable alternative to low density polyethylene films for soil mulching in horticulture. A mulch was created by spraying over the soil a sodium alginate water-based solution that, at the end of the cultivation cycle, could be tilled into the soil to be biodegraded. The mechanical and radiometric properties, the functionality of the spray coating, and its biodegradation were assessed by means of laboratory measurements and cultivation field tests. In the field, during the cultivation of strawberries, the spray coating was compared with a low density polyethylene mulching film and a straw mulch. The mechanical properties of the coating degraded when exposed in the field, but the coating kept its mulching effect for 6 months. The radiometric properties varied without regular trends, but the coating maintained its capacity to suppress weeds. The biodegradation tests showed that the spray coating samples biodegraded by 65% after 6 months into the soil.