Alternative Method of Agroclimatic Zoning of Maize for the State of Alagoas

The cultivation of corn under a rainfed regime along the state of Alagoas is deeply influenced by climate variability, especially when considering the recurring droughts affecting the entire Northeast region of Brazil. One way of minimizing the risk of losses is establishing a climate window that is optimal for the sowing time. This study resorted to an agrometeorological model of damages by water deficit to simulate the productivity in every municipality of Alagoas from 1980 to 2015. The high correlation between simulations and observations, and the low absolute mean error for reference stations validated the model. There are different windows favourable to planting, shorter in the hinterland during the month of April, between the third ten days of March and the third ten days of May in the wild, and between the first ten days of March and the second ten days of June in eastern Alagoas. On average, relative productivity losses are about 45% in “Sertão”, 40-45% in “Agreste”, and around 20% in the coast. Such results can aid the Brazilian Ministry of Agriculture, Livestock, and Supply, in the elaboration of its Agricultural Climate Risk Zoning of Crops, potentially resulting in a more considerate calendar for corn sowing in Alagoas.

巴西阿拉戈斯州（Alagoas）境内采用雨养耕作制度（rainfed regime）的玉米种植，深受气候变率（climate variability）影响，在巴西东北部地区（Northeast region of Brazil）全域遭遇周期性干旱（recurring droughts）的背景下尤为显著。降低种植损失风险的有效途径之一，是确立适配播种期（sowing time）的最优气候窗口（climate window）。本研究借助水分亏缺损失农业气象模型（agrometeorological model of damages by water deficit），模拟了1980年至2015年间阿拉戈斯州各自治市（municipality）的玉米生产力（productivity）水平。模拟结果与实测数据间的高相关性，以及参考站（reference stations）的低绝对平均误差（absolute mean error），验证了该模型的可靠性。该区域存在多类适宜播种窗口：内陆地区的适宜播种期较短，仅为4月；全域内陆区域的适宜期为3月下旬至5月下旬；阿拉戈斯州东部地区的适宜期则为3月上旬至6月中旬。平均而言，塞拉多（Sertão）地区的相对产量损失约为45%，阿格雷斯特（Agreste）地区为40%~45%，沿海地区约为20%。上述研究结果可为巴西农业、畜牧和供给部（Brazilian Ministry of Agriculture, Livestock, and Supply）制定作物农业气候风险区划（Agricultural Climate Risk Zoning of Crops）提供参考，有望助力阿拉戈斯州优化玉米播种日历。