覆蓋材料對‘臺農17號’鳳梨植株溫度與裂梗率的影響

Effects of Covering Materials on Plant Temperatures and Fruit Stalk Cracking Rates of 'Tainung No. 17' Pineapples

本研究探討覆蓋材料對‘臺農17號’鳳梨植體降溫、結實率及裂梗率之影響。正午時段在對照區域處（未覆蓋）所測得的溫度，高於同時期的氣溫及進行覆蓋者相對位置處的溫度；自果園中拍攝熱像圖，顯示未覆蓋者花穗梗最低溫度為30.6℃，而覆蓋雙層黑色50%遮光網及單層泰維克布之花穗梗處，其最低溫度分別為29.9℃及28.5℃，均低於對照。在催花後覆蓋雙層黑色50%遮光網會降低結實率，僅83.3%。紅喉後2週未覆蓋（對照）者之鳳梨裂梗率為22.2%，至接近始花期未覆蓋者之平均鳳梨裂梗率為50%；覆蓋單層白色聚乙烯纖維布（Tyvek布）或雙層黑色50%遮光網，可降低裂梗發生比率，分別為8.6%及10.0%。 Different covering materials are untilized to study their impacts on plant temperature cooling, fruitage percentage and fruit stalk cracking of 'Tainung No. 17' pineapple. Therefore, data carefully collected and recorded in this research include hourly average temperature, relative humidity, wind speed and solar radiation in pineapple orchard during experimental period. Fruitage percentage significantly decreased to 83.3% only in fields covered with double layer of 50% shading net. Without any covering material as check, fruit stalk cracking was high, up to 22.2% after 2 weeks of red heart stage, and average fruit stalk cracking was even higher, up to 50% when near flowering. This study has shown fruit stalk cracking can be effectively improved by the use of both mono layer of white polyethylene fibers and double layer of 50% shading net, with the incidence of only 8.6% and 10.0%, respectively. The temperatures on the surface of check are higher than that of the air and materials covered plants. Besides, thermography images were taken and the minimum fruit stalk temperature of plants without any covering material was 30.6℃.As result, mono layer of white polyethylene fibers and double layer of 50% shading net were both lower than that of the former with the minimum temperature of 28.5℃ and 29.9℃, respectively.