Germination and longevity of Echinochloa crus-galli L. under natural conditions.
In pot and field studies, freshly collected E. crus-galli seeds showed complete dormancy. Soil stored seeds under natural conditions had staggered germination from May to Sep. During one season 97.7% of the seed reserves were exhausted and only 2.3% were carried over to the second season. By the third season the soil was free of viable seed. The high population of E. crus-galli in rice fields was due to new seed added every season.