Agriculture Reference
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number and mass were significantly shallower with plants than without them.
Furthermore, the total reflected mass of water and the mass reflective factor
(percentage of incident mass) were considerably decreased by the presence of
strawberry plants (Fig.16.6). An inverse relationship between strawberry canopy
density and splash dispersal of
Colletotrichum acutatum
spores by simulated rainfall
has been observed (Boudreau and Madden, 1995). Three possible mechanisms for
decline in spore deposition were suggested: (i) decrease in the numbers of spores
removed from lesions, by splash or re-splash, because fewer raindrops reached
impaction sites; (ii) decrease in spore dispersal by secondary splash due to local
plant obstructions; (iii) direct interception of spore-carrying droplets by plant
surfaces.
0.4
0.8
M´
0.3
0.6
0.2
0.4
fm
0.1
0.2
0.0
0.0
0.0
1.0
2.0
3.0
Leaf area index
Figure 16.6. Influence of leaf area index on mass reflection and mass reflective factor
(percentage of incident mass) of simulated rainfall (intensity = 15 mm h ) falling across the
-
1
window of a rain shelter (see Fig. 16.5) on strawberry plants with soil ground cover. Points
are means of eight simulated rain events of 2 min each and correspond to three values of LAI
(from Yang and Madden, 1993).
