氣候變遷對農業長期生態系之影響長期觀測

Abstract

本研究之目的為探討氣候變遷對農業生態系之影響。由氣象資料顯示，雲林分場1988年至2013年呈現增溫之現象，而2000年至2013年各研究站平均氣溫並未呈現增溫趨勢；雨量方面顯示在2010年四月、2011年四月及2011年11月之雨量有明顯高於往年之情形。水稻產量部份，雲林分場與溪口農場之水稻產量與平均氣溫、生長積溫之間無顯著相關，但可看出產量隨平均氣溫與生長積溫上升而下降的趨勢；全台15個試驗點之水稻產量亦與平均氣溫、生長積溫並無顯著相關，但仍可看出水稻產量隨平均氣溫與最低氣溫上升而下降，反之隨最高氣溫上升而上升；DNDC對水稻生產模擬結果，未能呈現實際調查之南部產量高於北部之現象。水稻病害以稻熱病及紋枯病發生最多，在慣行農耕與永續農耕間無顯著差異；甘藷僅發生白絹病，在慣行農耕試驗田發生較輕微；落花生葉斑病在兩處理間發生情形相近，但銹病在慣行農耕發生率較低；荔枝酸腐病僅在慣行農耕試驗田發生輕微。在指標昆蟲方面，兩處理均以六條瓢蟲為優勢種，在年度間與多樣性方面則無明顯差異性。在雜草部份，永續農耕處理之平均雜草密度、平均雜草生質量以及每株雜草生質量皆高於慣行農耕區；輪作區之平均雜草生質量及每株雜草生質量高於連作區，而平均雜草密度則相反之。 The major aims of this study are to investigate the effect of climate change on agriculture system. For these aims, firstly, meteorological data are analyzed from three study stations of long term ecological research (LTER); include Yuin-Lin branch station, Chi-Ko branch farm, and Chia-Yi branch of Agricultural Research Institute. Air temperature keeps increasing from 1988 to 2013 in Yuin-Lin branch station; however, there are no significant differences from 2000 to 2013 in three LTER stations. Besides, rainfall in April 2010, April 2011, and November 2012 is higher than previous years. Secondly, there are no significant linear relationships between yields of rice grown and not only average air temperature, but also growing degree day (GDD) in Yuin-Lin and Chi-Ko, but the yield show a reducing trend if the average air temperature and GGD increase. Also, there are no significant linear relations between yields and not only average air temperature, but also GDD in 15 study stations around Taiwan, The yield in 15 study stations show a reducing trend if the average and minimum air temperature increase, but increasing if the maximum air temperature increases. Moreover, DNDC simulated model shows an inconsistent result with realistic situation which the yield in south area is higher than in north in Taiwan. Thirdly, the major rice diseases are rice blast and sheath blight, and the disease incidences have no significant differences between conventional (CA) and sustainable agroecosystem (SA). The major sweet potato disease is southern blight, and the disease incidence shows a slight serious condition in CA area. The major peanut diseases are leaf spot and rust. There are no significant differences in disease incidences of leaf spot between CA and SA, but the disease incidences of rust disease are lower in CA. Fourthly, the dominant indicator insect, ladybug, is Cheilomenes sexmaculata (Fabricius). But the biodiversity of ladybug has no differences in different years. Finally, average weed density, average weed fresh mass and single weed fresh mass are higher in SA than CA. Average weed fresh mass and single weed fresh mass are higher in paddy-upland cropping (PP) than paddy-paddy cropping (PP), but average weed density is just the reverse.