Effect of the seed morphological properties of some plant species on their loss from slope surfaces
2011
Parsakhoo, A., Ph.D. Student of Forest Engineering, Department of Forestry, Faculty of Natural Resources, Sari Agricultural Sciences and Natural Resources University, Sari, Iran
In this study the seed susceptibility of Poa annua L., Oxalis curniculatum, Medicago sativa and Rubus caesius L. species to wash or loss from slope surface was investigated. So, at first the mass, area, volume, density, surface to mass ratio, flatness index and eccentricity index of seeds was measured. 100 seeds from each species were distributed on sample plot with slope angle of 25, 45 and 65 degree and then rainfall simulation experiments were conducted on this plot during 40 minutes. Results showed that more seeds of Rubus caesius L. and Oxalis curniculatum have washed from surfaces with angles of 25, 45 and 65 degree at the first 10 minutes of rainfall simulation. During the rainfall simulation, Oxalis curniculatum seeds were more unstable than other seeds except for last 10 minutes on slope angle of 45 and 65 minutes. In this status the seed loss rate for Rubus caesius L. was more than other species. It seems that the reason of this issue be higher flatness index of Rubus caesius L. Poa annua L. was the most stable seed which had lowest loss rate during the rainfall simulation on slopes of 25, 45 and 65 degree. The seed loss rate increased with increasing slope angle. The most and least seed loss rate was occurred in slope angle of 65 and 25 degree, respectively.
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