In order to determine whether the current low productivity associated with rainfed cultivation on degraded soils in Ghana can be improved by biochar amendment and irrigation, field experiments with maize were conducted over two seasons in 2017 and 2018. Rice straw biochar at rates of 0 t/ha (B₀), 15 t/ha (B₁₅) and 30 t/ha (B₃₀) was combined with irrigation regimes of full irrigation (I₁₀₀), deficit irrigation (I₆₀) and no irrigation (I₀). The I₁₀₀ treatment was irrigated to field capacity every 3–4 days according to time domain reflectometry measurements while the I₆₀ treatment received 60% of the irrigation amount given to I₁₀₀ but with the same irrigation frequency. The I₀ treatment was not irrigated. In both seasons, the B₃₀ treatment recorded the highest total dry matter yield (TDMY), intercepted photosynthetically active radiation (IPAR) and radiation‐use efficiency (RUE) and these were significantly (p ≤ .05) higher than B₀ except for RUE in 2017. Irrigation regimes did not significantly affect TDMY, IPAR and RUE in 2017 but compared to I₁₀₀, I₀ significantly reduced TDMY, IPAR and RUE in the relatively dryer 2018 season. Measured ratio vegetation indices differentiated biochar treatments earlier in the 2018 season than during 2017 and increase of leaf chlorophyll content indices with biochar rate in both seasons indicated that biochar amendment improved nitrogen uptake. Our study demonstrated that rice straw biochar is capable of increasing TDMY, IPAR and RUE of maize grown on degraded soils in Ghana. The study further showed that TDMY, IPAR and RUE of deficit irrigated maize for two seasons were similar to the counterpart fully irrigated maize and may be a viable water management option for farmers in Ghana to save irrigation water resources.

中文翻译：

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稻草生物炭和灌溉对加纳Acrisol上玉米生长，干物质产量和辐射利用效率的影响

为了确定目前是否可以通过生物炭改良和灌溉来改善加纳退化土壤上的雨养栽培目前的低生产率，在2017年和2018年的两个季节中对玉米进行了田间试验。稻草生物炭的使用率为0 t / ha（B ₀），15 t / ha（B ₁₅）和30 t / ha（B ₃₀）与完全灌溉（I ₁₀₀），亏缺灌溉（I ₆₀）和不灌溉（I ₀）的灌溉制度相结合。根据时域反射测量，每隔3-4天将I ₁₀₀处理灌溉到田间容量，而I ₆₀处理则接受I处理的灌溉量的60％_100，但灌溉频率相同。I ₀处理未灌溉。在两个季节中，B ₃₀治疗记录的最高总干物质产量（TDMY），截获光合有效辐射（IPAR）和放射线利用效率（RUE），并且这些是显著（p  ≤0.05）高于乙₀除了2017年的RUE。灌溉制度在2017年对TDMY，IPAR和RUE的影响不显着，但与I ₁₀₀，I ₀在相对干燥的2018年季节中，TDMY，IPAR和RUE显着降低。实测比率植被指数在2018年季节比2017年期间更早地区分了生物炭处理，并且两个季节中叶绿素含量指数随生物炭比率的增加表明生物炭改良改善了氮的吸收。我们的研究表明，稻草生物炭能够增加在加纳退化土壤上生长的玉米的TDMY，IPAR和RUE。研究进一步表明，两个季节的缺水灌溉玉米的TDMY，IPAR和RUE与完全灌溉的玉米相似，可能是加纳农民节省灌溉水资源的可行水管理选择。