Study of Mulching Effect on Growth and Weed Control in Rabbiteye Blueberry (Vaccinium ashei) Cultivation in Taiwan

松樹皮覆蓋為美國商業生產藍莓的標準流程，但在臺灣不符合經濟效益。需要找到替代松樹皮且有效益的覆蓋方式。本論文以臺灣易取得、經濟效益高且物化性適合栽培藍莓使用之覆蓋物稻殼及銀黑色塑膠布作為覆蓋材料，以期達到與國外常用資材松樹皮相似之果園管理效果。於2015年春田間種植兔眼藍莓(V. ashei) ‘Blueshower’及 ‘Powderblue’，並以松樹皮、稻殼、塑膠布行覆蓋處，與無覆蓋之對照組比較。土壤pH及EC經過稻殼及松樹皮覆蓋與對照組無顯著差異，但塑膠布覆蓋下之土壤pH下降，且EC上升。夏季晴朗午後時，松樹皮及稻殼覆蓋降低土壤溫度，於冬季則提高土壤溫度，土壤含水率經過覆蓋顯著高於對照組。樹皮及稻殼覆蓋下顯著提高二次及三次梢的生長量與花芽數量，塑膠布覆蓋處理使休眠前落葉比率顯著提高。覆蓋處理後第一個生長季‘Blueshower’總葉面積以稻殼覆蓋處理之6858.2 cm2顯著高於對照組之5080.8 cm2，樹皮處理之5709.0 cm2及塑膠布處理組之5559.2 cm2則與對照組無顯著差異。2016年單株果實產量在稻殼及松樹皮覆蓋組較高，但糖度較低；塑膠布覆蓋組之果徑最小。樹皮及稻殼覆蓋之植株地表以上根系多於塑膠布及對照組，稻殼及松樹皮覆蓋組地表15公分以內根乾重及面積顯著高於對照組，根系面積在各處理間雖無顯著差異，但稻殼覆蓋使根徑1 mm以上根系之面積最高，樹皮覆蓋則使根徑1 mm以下之面積最高。雜草防治效果以塑膠布覆蓋最佳，稻殼與樹皮覆蓋相似，對照組雜草最多。稻殼分解速度較松樹皮快，須每年補充覆蓋物。總體而言稻殼與松樹皮覆蓋處理表現良好且相似，且稻殼兼具環保、實用及經濟性，可以作為臺灣替代松樹皮的良好選擇。Mulching with pine bark is a standard operation for commercial blueberry production in the USA. However, it is not economically practical in Taiwan. Alternatives with benefit similar to pine bark should be identified. Regarding the availability, economic efficiency and feasible chemical and physical properties, rice hull and silver-black plastic film were considered as potential candidates of mulching materials for blueberry cultivation. In this study, field grown ‘Blueshower’ and ‘Powderblue’ rabbiteye blueberries (Vaccinium ashei) were mulched with pine bark, rice hull, or silver-black plastic film, or not mulched as the control in 2015. Soil pH and EC were not significantly different among rice hull, or pine bark mulching and the control, but lower soil pH and higher soil EC were discovered with plastic mulching. Mid-day soil temperature under pine bark and rice hull were lower in the summer but higher in winter than the control. Soil moisture content was higher with mulching treatments than the control. Pine bark and rice hull mulching increased shoot length within the second and third flushes and number of flower buds per plant. Plastic mulching significantly increased number of defoliation before winter dormancy. Total leaf area by the end of the second flushing cycle in ‘Blueshower’ mulched with rice hull (6858.2 cm2) was significantly higher than the control (5080.8 cm2), but not different from pine bark (5709.0 cm2) or plastic film (5559.2 cm2). Fruit yield per plant in 2016 was higher but total soluble solids content was lower in plants mulched with rice hull or pine bark, berry size was smallest in plants mulched with plastic film. More roots developed on soil surface in the rice hull and pine bark mulching treatments compared to plastic film and the control. Root dry weight and root surface area in the upper 15 cm of soil increased with pine bark and rice hull mulching; however, total root area was not affected by treatments. The number of roots with diameter >1 mm was highest in plants mulched with rice hull, while the number of roots with diameter <1 mm was highest in plants mulched with pine bark. Plastic mulching was most effective on weed control than rice hull and pine bark mulching. Rice hull decomposed faster than pine bark, thus requiring supplement more frequently. Overall, rice hull performed well and was an environmental friendly, economical, and practical substitute of pine bark mulching for blueberry cultivation in Taiwan