Banana Yield Estimation (Irrigated Ratoon Crop)

Modern bananas originated in the southeast Asian and western Pacific regions, with earliest records of cultivation in India about 2 500 years ago (ARC, 2005). Bananas are stress sensitive plants which grow satisfactorily with a MAP of 1 200 mm, ideally well distributed throughout the year (Smith, 1998). Dry spells of more than 7 days are detrimental to yields. Preferring a relative humidity > 60 percent (especially during fruit setting), the mid-day RH should generally exceed 50 percent. The optimum mean monthly temperatures for bananas are 25 - 28 degree Celsius, with a range of 20 - 35 degree Celsius. Growth ceases below 12 degree Celsius and the July mean of daily minima should be at least 8 degree Celsius. Of the 1 200 ha under bananas, 64 percent are in Mpumalanga, 18 percent are in KwaZulu-Natal and a further 18 percent in Limpopo (Statistics SA, 2002). Highest average yields, around 26 t/ha/an, are attained in Mpumalanga, while those in KwaZulu-Natal and Limpopo are 20 t/ha/an, i.e. on the low side by international standards (Statistics SA, 2002).

Determination of banana yield estimates, based on Smith`s climatic criteria. Areas considered climatically unsuitable for banana production and thus eliminated from further analysis were those with MAP < 900 mm (for dryland production), MAT < 16 degree Celsius, July means of daily minimum temperatures < 8 degree Celsius, the averages of the 12 monthly means of daily maximum temperatures < 22 degree Celsius and of minimum temperatures < 10 degree Celsius, as well as areas where the mean of the 12 monthly values of daily minimum RH was < 50 percent

现代香蕉起源于东南亚及西太平洋地区，其最早的栽培记录可追溯至约2500年前的印度（ARC，2005）。香蕉为应激敏感型植物，在年平均降水量（MAP，Mean Annual Precipitation）达1200毫米且全年分布均匀的条件下生长状况良好（Smith，1998）。连续干旱超过7天会对产量造成不利影响。香蕉偏好相对湿度（RH，Relative Humidity）高于60%（尤其在坐果期），正午相对湿度通常应超过50%。香蕉生长的最适月平均温度为25-28摄氏度，温度范围在20-35摄氏度之间。当温度低于12摄氏度时生长停止，且7月日均最低温度均值应不低于8摄氏度。南非统计局（Statistics SA，2002）数据显示，香蕉种植面积共1200公顷，其中64%位于姆普马兰加省，18%位于夸祖鲁-纳塔尔省，其余18%位于林波波省。姆普马兰加省的平均产量最高，约为26吨/公顷/年，而夸祖鲁-纳塔尔省和林波波省的平均产量为20吨/公顷/年，即低于国际标准（Statistics SA，2002）。

基于Smith气候标准的香蕉产量估算方法。气候条件不适宜香蕉种植且因此被排除在进一步分析之外的区域包括：年平均降水量（MAP）<900毫米（旱地种植）、年平均气温（MAT，Mean Annual Temperature）<16摄氏度、7月日均最低温度均值<8摄氏度、12个月日均最低温度均值<10摄氏度，以及12个月日均最低相对湿度（RH）均值<50%的区域。