Robusta coffee, a vital cash crop for Vietnamese smallholders, significantly contributes to the national economy. Vietnam is the largest exporter of Robusta coffee, supplying 53% of the global market. However, this success has come at a cost. Decades of intensive Robusta coffee cultivation in Vietnam have led to severe soil acidification and biodiversity loss, favoring soil-borne pathogens. There is a lack of literature analyzing how intensive management causes soil acidification, advances the spread of soilborne pathogens, and the application of soil amendments to address these issues. Therefore, this review explores the causes of acidification, pathogen proliferation, and sustainable amendments like lime and biochar to mitigate these effects. The study synthesizes findings from studies on soil acidification, soil-borne pathogen dynamics, and sustainable soil amendments in Robusta coffee systems. We found that the overuse of nitrogen-based chemical fertilizers to grow coffee is the primary driver of soil acidification, consequently increasing soilborne diseases and the severity of plant diseases. Additionally, the effects of soil amendments as a sustainable solution to reduce soil acidity, enhance soil health, and better control soilborne pathogens. The implementation of sustainable coffee farming systems is strongly recommended to meet the increased demand for safe and green products worldwide. Locally available resources (lime, biochar, and agricultural wastes) present immediate solutions, but urgent action is required to prevent irreversible damage. However, the effects of amendments significantly vary in field conditions, suggesting that further studies should be conducted to address these challenges and promote sustainability.

Aluminium (Al) stress is the second-leading abiotic stress on crops. An improved understanding of the response mechanisms of plants to Al stress will provide scientific guidance for enhancing the crops' tolerance to Al stress. In this study, Al stress (50-200 mu M AlCl3) caused visible damage to broad bean (Vicia faba L.) roots rather than shoots, which was attributed to Al accumulation and distribution in different tissues. Root transcriptomic analysis revealed that Al stress altered cell wall properties by downregulating lignin synthesis and several xyloglucan endotransglucosylase/hydrolase-, expansin- and peroxidase (POD)-encoding genes, which likely weakened cell extensibility to inhibit root growth. Additionally, Al stress impeded reactive oxygen species scavenging pathways involving POD activity and flavonoid biosynthesis, leading to oxidative damage characterised by malondialdehyde accumulation. These results indicate that optimising cell wall properties and/or enhancing antioxidant processes are crucial for alleviating Al toxicity to broad beans. Interestingly, exogenous application (500 and 1000 mu M) of the flavonoid apigenin effectively alleviated Al toxicity in broad bean roots by partially improving the total antioxidant capacity of the roots. This study contributes to understanding the interaction between plants and Al and provides new strategies to alleviate Al toxicity in crops.

Magnesium plays a crucial role in plant physiological processes. However, the specific mechanisms underlying the response of tea plants to altered magnesium nutrition under acid stress remain unclear. This study investigates how root environment acidification impacts tea seedlings and the role of magnesium (Mg) in mitigating these effects. We examine varying pH and Mg levels' influence on tea seedlings' resistance to abiotic stress, focusing on antioxidant capacity and nutritional content. In a hydroponic experiment, we varied root pH (3.5, 5.0, 6.5) and Mg concentrations (0.01, 0.4, 0.8 mM), assessing parameters like antioxidant capacity, peroxidative damage, and nutritional content at 1, 7, 15, and 30 days post treatment. Root environment acidification and Mg deficiency worsened peroxidative damage in tea plant leaves and roots. Increased Mg supplementation enhanced antioxidant enzyme activity, reducing malondialdehyde and mitigating oxidative damage from root environment acid stress. Under acid stress, 0.8 mM Mg significantly increased tea leaf polyphenols, amino acids, and water-soluble extracts. Mg notably boosted chlorophyll content, surpassing lower Mg levels at pH 5. Additionally, Mg reversed root vitality inhibition induced by acid stress, leading to increased nitrogen, potassium, and Mg concentrations in leaves, promoting balanced nutrient absorption. Mg supplementation is crucial for enhancing tea plant antioxidant capacity, alleviating growth inhibition from root-environment acid stress, and improving chlorophyll content and root vitality, highlighting Mg's significance in tea cultivation and broader agricultural practices.

Over -application of nitrogen fertilizer induces soil acidification, which activates heavy metals availability and poses significant challenge to crop production and food safety. In this study, we prepared a clay-based material by ball-milling bentonite with NH4Cl (NH4Cl@bentonite) and assessed its synergistic performance in enhancing nitrogen fertilizer utilization efficiency, immobilizing heavy metals, and improving crop yield and safety. The results showed that the optimal performance of NH4Cl@bentonite was achieved by milling bentonite with NH4Cl at a 4:1 mass ratio for 9 h. NH4Cl@bentonite significantly improved soil water holding and retention capacity by 1.6 and 4.3 times, respectively. In comparison to NH4Cl alone, NH4Cl@bentonite led to a 22.3% increase in N -use efficiency and a 1.5 times enhancement in crop yield. The Pb and Cd content in water spinach shoots decreased by 55.3% and 57.5%, respectively, attributed to the transformation of heavy metals into lower bioavailability states by NH4Cl@bentonite. Experiments and Density Functional Theory (DFT) calculations indicated that NH4Cl@bentonite could immobilize Pb and Cd through processes such as cation exchange, surface adsorption, complexation, and enhancement of soil pH. This work proposes a simple and efficient method for improving cropland fertilizer utilization while ensuring healthy and sustainable development. Environmental implication: Soil acidification, caused using chemical fertilizers, especially nitrogen -based ones, threatens crop production and food safety by damaging soil structure, speeding up nutrient loss, and increasing the solubility of heavy metals. To tackle this problem, we made a clay material by mixing bentonite with NH4Cl (NH4Cl@bentonite) in a ball mill. NH4Cl@bentonite increased N -use efficiency by 22.3%, boosted crop yield by 1.5 times, and reduced the Pb and Cd levels in water spinach shoots by 55.3% and 57.5%, respectively. This work suggests a simple and effective way to enhance fertilizer use in croplands while ensuring healthy and sustainable development.