Identifying options for the sustainable intensification of cropping systems in southern Africa under prevailing high climate risk is needed. With this in mind, we tested an intercropping system that combined the staple crop maize with lablab, a local but underutilised legume. Grain and biomass productivity was determined for four variants (i) sole maize (sole-maize), (ii) sole lablab (sole-lablab), (iii) maize/lablab with both crops sown simultaneously (intercropped-SP) and (iv) maize/lablab with lablab sown 28 days after the maize crop (intercropped-DP). Soil water and weather data were monitored and evaluated. The trial was conducted for two seasons (2015/2016 and 2016/2017) at two sites in the Limpopo Province, South Africa: Univen (847 mm rainfall, 29.2 °C maximum and 18.9 °C minimum temperature average for the cropping season over the years 2008–2017) and Syferkuil (491 mm rainfall, with 27.0 °C maximum and 14.8 °C minimum temperature). Analysis revealed three key results: The treatment with intercropped-SP had significantly lower maize yields (2320 kg ha−1) compared with maize in intercropped-DP (2865 kg ha−1) or sole-maize (2623 kg ha−1). As expected, maize yields in the El Niño affected in season 2015/2016 were on average 1688 kg ha−1 lower than in 2016/2017. Maize yields were significantly lower (957 kg ha−1) at Univen, the warmer site with higher rainfall, than at Syferkuil. In 2015/2016, maximum temperature at Univen exceeded 40 °C around anthesis. Furthermore, soil water was close to the estimated permanent wilting point (PWP) for most of the cropping season, which indicates possible water limitations. In Syferkuil, the soil water was maintained well above PWP. Lablab yields were low, around 500 ha−1, but stable as they were not affected by treatment across season and site. Overall, the study demonstrated that intercropped-DP appears to use available soil water more efficiently than sole maize. Intercropped-DP could therefore be considered as an option for sustainable intensification under high climate risk and resource-limited conditions for smallholders in southern Africa.

中文翻译：

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玉米实验室间作有望支持南部非洲高气候风险下小农种植系统的可持续集约化

需要在普遍存在的高气候风险下确定南部非洲种植系统可持续集约化的选择。考虑到这一点，我们测试了一种间作系统，该系统将主要作物玉米与当地但未充分利用的豆科植物 lablab 相结合。测定了四种变体的谷物和生物量生产力（i）单一玉米（sole-maize），（ii）单一实验室（sole-lablab），（iii）玉米/实验室同时播种两种作物（间作-SP）和（iv ) maize/lablab with lablab 在玉米作物播种后 28 天（间作-DP）。监测和评估土壤水分和天气数据。该试验在南非林波波省的两个地点进行了两个季节（2015/2016 和 2016/2017）：Univen（降雨量 847 毫米，最高 29.2 °C 和 18. 2008-2017 年种植季节的最低平均温度为 9°C）和 Syferkuil（降雨量为 491 毫米，最高温度为 27.0°C，最低温度为 14.8°C）。分析揭示了三个关键结果： 间作 SP 处理的玉米产量显着降低（2320 kg ha-1) 与间作 DP (2865 kg ha) 中的玉米相比-1) 或单一玉米（2623 公斤公顷-1）。正如预期的那样，2015/2016 年度受厄尔尼诺影响的玉米平均产量为 1688 公斤公顷-1低于 2016/2017 年。玉米产量显着降低（957 公斤公顷-1) 在 Univen，比 Syferkuil 更温暖，降雨量更高。在 2015/2016 年，Univen 的最高温度在开花前后超过了 40 °C。此外，在大部分种植季节，土壤水分接近估计的永久萎蔫点（PWP），这表明可能存在水分限制。在 Syferkuil，土壤水分保持在 PWP 以上。Lablab 产量很低，大约 500 公顷-1，但稳定，因为它们不受季节和地点的治疗影响。总体而言，该研究表明，间作 DP 似乎比单一玉米更有效地利用了可用的土壤水分。因此，对于南部非洲的小农来说，间作 DP 可被视为在高气候风险和资源有限条件下可持续集约化的一种选择。