Soil acidity is one of the major soil-degradation events throughout the world, and the long-term application of nitrogenous fertilizers is thought to be a main cause of soil acidity. In the present experiment, we collected soil and tea (Camellia sinensis L.) leaf samples from five representative tea gardens in Bangladesh and evaluated soil nutrient pools and biochemical properties of tea leaves. The results showed that there was a negative relationship between soil pH and the amount of applied nitrogenous fertilizers. Moreover, continuous application of traditional fertilizers over twenty-five years promoted not only the deficiency of phosphorus (P) and mineral-based cations, such as potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺), but also increased manganese (Mn²⁺) and aluminum (Al³⁺) toxicity in soils, which suppressed the yield and quality of tea. Crucially, tea leaf production remained almost similar (average 1079.77 kg ha⁻¹) from 1995 to 2015, while the application doses of urea, TSP, and MoP increased by 24.69%, 18.92%, and 16.67%, respectively, in garden soils. However, the pH value of soil declined up to 24% from 1992 to 2020 in the tested gardens. Consequently, the availability of K⁺, P, Ca²⁺, and Mg²⁺ decreased by 56%, 25%, 55%, and 49%, respectively, in those tea garden soils. In addition, the quality of tea leaves was severely affected, as evident by the reduced levels of total flavonoids, polyphenols, soluble solids, vitamin C, vitamin B1, and vitamin B2. Moreover, free-radical scavenging activity (DPPH), caffeine, and tannin concentration were increased in tea leaves, which indicated that tea plants were potentially being stressed. Therefore, we study concluded that long-term application of traditional nitrogenous fertilizers can be an important regulator of lowering garden soil pH, which reduces native soil nutrient pools and thereby the yield and quality of tea leaves.

Soil acidity is a divesting factor that restricts crop growth and productivity. Conversely, silicon nanomaterials (Si-NMs) have been praised as a blessing of modern agricultural intensification by overcoming the ecological barrier. Here, we performed a sequential study from seed germination to the yield performance of mustard (Brassica campestris) crops under acid-stressed conditions. The results showed that Si-NMs significantly improved seed germination and seedling growth under acid stress situations. These might be associated with increased antioxidant activity and the preserve ratio of GSH/GSSG and AsA/DHA, which is restricted by soil acidity. Moreover, Si-NMs in field regimes significantly diminished the acid-stress-induced growth inhibitions, as evidenced by increased net photosynthesis and biomass accumulations. Again, Si-NMs triggered all the critical metrics of crop productivity, including the seed oil content. Additionally, Si-NMs, upon dolomite supplementation, further triggered all the metrics of yields related to farming resilience. Therefore, the present study highlighted the crucial roles of Si-NMs in sustainable agricultural expansion and cropping intensification, especially in areas affected by soil acidity.

Silicon-nanomaterials (Si-NMs) have emerged as a revolutionary tool in modern agriculture; however, the collaborative role of Si-NMs in onion crop productivity and expansion in acidic soils remains elusive. We conducted a series of sequential experiments, from seed germination to field trials, over two consecutive cultivation years. Intriguingly, the results revealed that among the differential doses, 1.0 mM L⁻¹ of Si-NMs significantly ameliorated the acid-stress-induced suppression of onion seed germination and seedling growth. Additionally, a selected dose of Si-NMs reduces seedling mortality and improves plant establishment rate with increased photosynthetic performance, bulb properties, and nutritional quality. These stimulatory effects of Si-NMs on onion crop adaptation to acidic soil were associated with reduced ROS accumulation driven by enhanced antioxidant potential, which further increased upon dolomite supplementation. Furthermore, exogenous Si-NMs spray accelerated the early stages of harvestable onion size, accompanied by increased synthesis of IAA and GA₃ hormones, suggesting the potential of Si-NMs to enhance farm resilience in acidic soils.