**2.2 Soil testing for maize production**

Soil testing holds a pivotal role in optimizing nutrient management specifically tailored for maize production. By analyzing soil samples, farmers gain invaluable insights into the soil's nutrient content and pH levels, enabling them to make wellinformed decisions regarding fertilizer application. Recent research papers have extensively highlighted the profound significance of soil testing in this context. In a notable study conducted between 2015 and 2016, the focus was on bridging the maize yield gap and enhancing soil properties in coastal saline soil. The researchers explored the efficacy of a combined application of flue gas desulfurization gypsum and furfural residue (known as CA). Intriguingly, the post-harvest CA treatment exhibited remarkable outcomes, with notable increases observed in calcium (Ca2+) and soil organic carbon (SOC) contents, while simultaneously reducing sodium (Na+) content and pH levels in the upper soil layer. Consequently, maize crops experienced significant enhancements in nitrogen, phosphorus, potassium,

calcium, and magnesium accumulations, alongside a decrease in Na accumulation when compared to the control group [22]. Another noteworthy study delved into the dynamics of global maize production, consumption, and trade, aiming to decipher evolving trends over the past 25 years and their consequential impact on research and development (R&D), with a particular focus on the Global South. The study emphasized the pressing need for augmented investments in R&D endeavors to fortify maize's pivotal role in ensuring food security, sustaining livelihoods and effectively intensifying production, all while adhering to the constraints imposed by planetary boundaries [23]. These research findings substantiate the indispensability of soil testing in the realm of maize production. Moreover, they underscore the necessity for further exploration to develop innovative and more potent methodologies aimed at improving soil properties and elevating maize yields. As such, these insights reinforce the critical role that soil testing plays in optimizing nutrient management strategies, customizing fertilizer application practices, and addressing the overarching global challenges associated with maize cultivation. Soil testing occupies a central position in the intricate web of nutrient management for maize production. Recent research profoundly accentuates its significance in fine-tuning fertilizer application, ameliorating soil characteristics, and ultimately bolstering maize yields. By diligently incorporating soil testing into their agricultural practices, farmers can aptly discern the most optimal courses of action, thereby maximizing nutrient utilization, mitigating environmental repercussions, and fostering sustainable and prosperous maize farming [24–27].
