The Effects of Climate Change on Sugar Beet Yield with an Emphasis on Crop Production Risk in Iran

Climate change and the resulting changes in climatic parameters influence all agricultural activities. The present study aimed to explore the effect of climatic variables on sugar beet crop yield in two climates – cold climate and hot and arid climate – using the Just and Pope stochastic function. First, the most effective climatic variables on sugar beet yield were identified by the Feiveson algorithm and the Just and Pope function. Data stationarity test was applied to assess the stationarity of the included variables. The interrelationship of the dependent and independent variables was analyzed by the co‐integration test. Finally, the coefficients of the Just and Pope function for sugar beet crop in two studied climates for the time period of 1998‐2017 were estimated. The results of sugar beet yield function in cold regions show that sugar beet yield in cold regions was significantly influenced by acreage and maximum temperature at p&lt;0.10 level and by minimum temperature deviation, production lag, and trend at p&lt;0.01 level, but the variable of precipitation was significant in none of the levels. The estimation of the Just and Pope function for sugar beet crop in hot and arid regions indicates that the effects of maximum temperature, production lag, and trend are significant on sugar beet yield at p&lt;0.05 level, but the effects of acreage, precipitation deviation, and minimum temperature deviation were insignificant. Given temperature variations and unexpected precipitation, it is recommended to encourage sugar beet farmers to use crop insurance in order to mitigate local farmers’ risk and alleviate the damages of climate change.气候变化及其引发的气候参数改变，会对所有农业生产活动造成影响。本研究采用贾斯特-波普随机函数（Just and Pope stochastic function），探究寒冷气候与炎热干旱气候两种环境下，气候变量对甜菜作物产量的影响。首先，通过费伊夫森算法（Feiveson algorithm）与贾斯特-波普随机函数，筛选出对甜菜产量影响最为显著的气候变量；随后通过数据平稳性检验，评估纳入分析变量的平稳性；再借助协整检验（co-integration test）分析因变量与自变量间的相互关系；最终估算出1998-2017年两个研究气候区中，甜菜作物的贾斯特-波普随机函数各项系数。寒冷地区甜菜产量函数的结果显示：该区域甜菜产量在p<0.10的显著性水平下，受种植面积与最高气温显著影响；在p<0.01的显著性水平下，受最低气温偏差、生产滞后期与时间趋势显著影响；而降水变量在所有显著性水平下均无显著关联。针对炎热干旱地区甜菜作物的贾斯特-波普随机函数估算结果表明：最高气温、生产滞后期与时间趋势对甜菜产量的影响在p<0.05的显著性水平下显著，而种植面积、降水偏差与最低气温偏差的影响则不显著。鉴于气温波动与非预期降水事件，本研究建议鼓励甜菜种植户投保作物保险，以降低当地农户的生产风险，减缓气候变化带来的损失。