San Luis Obispo, CA -- A 75-acre prescribed burn one mile east of Islay Hill in southeast San Luis Obispo is planned for Friday. Three engines and one fire crew will control the burn. Several agencies are working together on burn to study the effectiveness of using fire to manage medusa head grass, which is an invasive weed that overcrowds native species in pastures and rangelands. The grassy weed is also said to increase fire danger as it builds up year after year. People in the southern end of San Luis Obispo or traveling Edna Road and Orcutt Road may see smoke on the east side of Edna Valley near Biddle Road from 9 o’clock in the morning until to 4 o’clock in the afternoon Friday. The project is dependent on weather and will be rescheduled if conditions that day could interfere with putting out the fire or dispersing the smoke.