Effects of reflective mulching sheets on the light environment in citrus orchards

摘要

From July to September, I compared the effects of bare ground (control) and different reflective mulching sheets on the light environment and insect flight behavior in a citrus orchard (satsuma mandarin/Ehime-Nakate). The results showed that AFP sheets laid outside the canopy of satsuma mandarin at 0 m (15 cm) above ground level reflected the greatest quantity of light. Light quantity was reduced in the canopy over bare ground, whereas the level of light at 0 and 1 m above ground level increased withthe application of mulching sheets. Insects were captured using sticky traps in each treatment area, and the numbers and species (orders) varied depending on the type of mulching sheets. Moreover, in summer, the number of insects captured over some reflective mulching sheets (420-470, 520-570, and 570-620 nm) was nearly only half of that caught over bare ground. The numbers of insects trapped over all types of mulching sheet were significantly lower than those trapped over bare ground. In summary, theapplication of mulching sheets in a citrus orchard changed the profile of the light environment inside and outside the crown of satsuma trees, and also altered the flight behavior and populations of insects.