Its membrane is stable for up to about 40 hours and can be reused within that period for any number of measurements. ARS scientists codeveloped the biosensor with scientists from the Czech Republic and Italy through a grant supported by the North American Treaty Organization. The Jornada is in the northern part of the Chihuahuan Desert, one of the driest spots in the country and the largest desert in North America. In each package, seeds are tucked into three little pipes, which in turn are set within a larger pipe. If enough rain falls, a streamlet with sufficient force will break through crepe paper covering both ends of the lowest seed pipe.
Seeds then flow out through a mesh screen on the end of the outer, larger pipe.
Seed is released only when rain falls. This ensures that all the seed is released only when there is enough rain to spread it far downstream. The rain also ensures that seeds are deposited in moist soil with a mulch cover of grass stem litter naturally carried by streamlets. The scientists are monitoring results to see if stream-seeded plants eventually spread to cover large areas of bare ground.