Sorghum production is constrained by terminal drought stress in semi-arid areas of north-eastern Ethiopia. Data from field experiments conducted in the region for two consecutive years (2015 – 2016) were used to investigate the effect of potassium (K) and NPSBZn-blended fertilizer (BF) inputs on the drought response of sorghum through analysis of gas exchange, dry matter accumulation and growth parameters. Leaf gas exchange properties varied strongly with K and BF application both under normal rainfall and drought conditions. Data taken at anthesis in drought-exposed sorghum indicated reduction of net photosynthetic rate (A_N) with BF supply. A_N declined from 15.7 µmol CO₂/m²/s in the control to 13.4 µmol CO₂/m²/s with application of 164 kg/ha BF. However, higher total dry matter yield was recorded at maturity in response to blended fertilizer and K inputs. Increasing supply of NPSBZn-blended fertilizer was associated with declining leaf K content, increasing intercellular CO₂ concentration and water use efficiency (WUE) during anthesis. Significant variations in crop growth rates were also observed in response to K and BF inputs. At physiological maturity, net assimilation rate (NAR) increased with K and BF inputs both under drought and normal rainfall conditions. In general, K application modulated the response of sorghum to BF input under both normal rainfall and drought conditions. Therefore, grain sorghum could benefit from early supply of K and BF fertilizer in drought prone areas of Northeastern Ethiopia.

中文翻译：

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高钾（混合高粱）的施肥对高粱的CO2交换，干物质积累和生长响应的最终干旱。

高粱产量受到埃塞俄比亚东北部半干旱地区终极干旱胁迫的限制。该地区连续两年（2015年至2016年）进行的田间试验数据被用于通过气体交换，干燥分析来研究钾（K）和NPSBZn混合肥料（BF）投入对高粱干旱响应的影响。物质积累和生长参数。在正常降雨和干旱条件下，施用钾肥和高炉肥后，叶片气体交换特性差异很大。在干旱暴露的高粱上，开花期获得的数据表明，高炉供应会降低净光合速率（A _N）。甲_Ñ从15.7下降微摩尔CO ₂ /米²在控制/ s至13.4微摩尔CO ₂/ m ² / s，施加164 kg / ha BF。但是，由于肥料和钾的混合投入，成熟期的干物质总产量更高。NPSBZn混合肥料的供应增加与叶片钾含量下降，细胞间CO ₂增加有关花期的浓度和水分利用效率（WUE）。还观察到了对钾和高炉投入的作物生长速率的显着变化。在生理成熟期，在干旱和正常降雨条件下，净同化率（NAR）随钾和高炉投入的增加而增加。通常，在正常降雨和干旱条件下，钾肥的施用都会调节高粱对高炉BF输入的响应。因此，在埃塞俄比亚东北部干旱多发地区，谷物高粱可从钾和高炉肥料的早期供应中受益。