運用氣象資料預測當期荔枝產量之可行性研究

Abstract

荔枝產量每年受到冬季氣溫影響甚劇，低溫可刺激花芽穩定分化，但遇到暖冬年則因花芽分化不穩定與開花比例下降導致減產。本研究調閱主產區鄰近氣象站過去9 年11 月至隔年2 月的氣象資料，將每日處於10–35℃的小時數加總後，依荔枝品種不同分別與當期批發市場荔枝交易總量進行回歸分析。結果顯示12 月的氣溫與當期的產量相關性最高，並以『較長的低溫期』比『較寒冷的溫度』對產量的影響更關鍵，「玉荷包」、「黑葉」與「糯米糍」荔枝分別在每日低於24℃、13℃與22℃的小時數加總與當期產量進行回歸分析的決定係數 (R2) 可達0.6938、0.8578 與0.8215。本研究結果顯示，未來可依荔枝品種不同，將產區12 月低於特定溫度的小時數加總後帶入回歸方程式計算，即可提早預估當年度的荔枝產量。此創新方法可作為農政單位產銷調節，或荔枝產銷業者提早規劃內外銷訂單之參考資料。 The annual yield of litchi is greatly affected by the temperature in winter. Low temperature can stimulate the stable differentiation of flower buds. However, the production will be reduced due to unstable differentiation of flower buds and decreased flowering ratio in mild winter. This study considers different litchi varieties, which are distributed in the main producing areas in Taiwan. The meteorological data was collected from November to February of the following year in the past 9 years close to the weather station in the main producing area. The sum of the daily hours ranging from 10℃ to 35℃ and the total sale volume of litchi in the auction market in the current season were evaluated by regression analyses. The results indicated that the temperature in December had the highest correlation with the auction market sold litchi amount in the current year. A longer low temperature period was more critical to yield than colder temperature. The accumulated daily differential hours below 24℃, 13℃ and 22℃, respectively, and the previous sold amounts of ‘Yu-Her-Bao’, ‘Hei-Yeh’ and ‘No-Mai-Tsz’ litchi in the recent years are processed for correlation analysis. The coefficients of determination (R2) reached 0.6938, 0.8578, and 0.8215, respectively. In the future production estimation, depending on the variety, the number of hours below the threshold temperature in December could be applied to the equation to predict the litchi yield in the current year. This innovative method can be used as a reference for the production and sales adjustment of agricultural sector or for litchi operators to plan domestic and foreign sales orders in advance.