International Institute of Tropical Agriculture, Nairobi, Kenya.
International Institute of Tropical Agriculture, Kano, Nigeria.
PLoS One. 2024 May 2;19(5):e0300427. doi: 10.1371/journal.pone.0300427. eCollection 2024.
Climate change and inter-annual variability cause variation in rainfall commencement and cessation which has consequences for the maize growing season length and thus impact yields. This study therefore sought to determine the spatially explicit optimum maize sowing dates to enable site specific recommendations in Nigeria. Gridded weather and soil data, crop management and cultivar were used to simulate maize yield from 1981-2019 at a scale of 0.5°. A total of 37 potential sowing dates between 1 March and 7 November at an interval of 7 days for each year were evaluated. The optimum sowing date was the date which maximizes yield at harvest, keeping all other management factors constant. The results show that optimum sowing dates significantly vary across the country with northern Nigeria having notably delayed sowing dates compared to southern Nigeria which has earlier planting dates. The long-term optimal sowing dates significantly (p<0.05), shifted between the 1980s (1981-1990), and current (2011-2019), for most of the country. The most optimum planting dates of southern Nigeria shifted to later sowing dates while most optimum sowing dates of central and northern Nigeria shifted to earlier sowing dates. There was more variation in optimum sowing dates in the wetter than the drier agro-ecologies. Changes in climate explain changes in sowing dates in wetter agro-ecologies compared to drier agro-ecologies. The study concludes that the optimum sowing dates derived from this study and the corresponding methodology used to generate them can be used to improve cropping calendars in maize farming in Nigeria.
气候变化和年际变化导致降雨开始和结束的变化，这对玉米生长季节的长度有影响，从而影响产量。因此，本研究旨在确定明确的玉米最佳播种日期，以便在尼日利亚进行具体的现场推荐。本研究使用网格化的天气和土壤数据、作物管理和品种，模拟了 1981 年至 2019 年期间玉米的产量，模拟的空间分辨率为 0.5°。总共评估了每年 3 月 1 日至 11 月 7 日之间的 37 个潜在播种日期，间隔为 7 天。最佳播种日期是在保持所有其他管理因素不变的情况下，使收获时产量最大化的日期。结果表明，最佳播种日期在全国范围内差异显著，与南部相比，北部尼日利亚的播种日期明显推迟，而南部的播种日期更早。在大多数国家，长期的最佳播种日期在 20 世纪 80 年代（1981-1990 年）和当前（2011-2019 年）之间有显著（p<0.05）的变化。南部尼日利亚的最佳种植日期向较晚的播种日期转移，而中部和北部尼日利亚的最佳播种日期向较早的播种日期转移。在较湿润的农业生态区，最佳播种日期的变化比较干旱的农业生态区更大。与较干旱的农业生态区相比，气候的变化可以解释较湿润的农业生态区播种日期的变化。本研究得出结论，从本研究中得出的最佳播种日期和生成这些日期所使用的相应方法，可以用来改进尼日利亚玉米种植的种植日历。
