Surfactant-coated Seed Emergence and Establishment Under Deficit Irrigation in Hydrophilic and Hydrophobic Soils

Soil water repellency inhibits seed germination and emergence, whereas soil surfactants improve the wettability of water-repellent or hydrophobic soils. An improvement in seed germination and emergence can occur when a soil surfactant is applied directly to the seed and/or to the water repellent soil at sowing. Therefore, a coating process was developed to utilize seed as a soil surfactant carrier. Greenhouse experiments were conducted to evaluate establishment of perennial ryegrass (Lolium perenne L.) seed coated with a soil surfactant (SCS = surfactant-coated seed), as compared to uncoated seed (CHK). Both SCS and CHK were sown in two hydrophilic substrates (100% sand [WSAND], 90:10% v/v sand:peat [WSP], and in two severely hydrophobic sands (100% hydrophobic stearic acid-treated sand [HSS], and hydrophobic 90:10% v/v sand:peat [HSP]). Due to the weight of the coating, SCS was sown at half the amount as compared to CHK; however, final turfgrass establishment in all rootzones with SCS was similar or better than CHK. In WSAND, WSP, and HSP, the volumetric water content was consistently higher in rootzones of SCS treatments versus CHK. SCS represents an opportunity to improve stand establishment and rootzone soil-water dynamics in challenging environmental conditions such as limited precipitation.