## 3 Results and Discussions
### Early Growth Stage  
In addition to evaluating the performance of various dosages of P-BC-LDHs on seed germination, fertilizer administration is also critical during the initial period of plant development in order to maintain adequate nutrient levels for crop nutrition. Furthermore, because nutrient requirements vary depending on the crop growth stage, such a relationship would be synergistic at a certain concentration range of P-BC-LDHs but may become antagonistic when its concentration is too high. In these contexts, the successive early-stage growth responses of lettuce in relation to the application of P-BC-LDHs were evaluated. In these experiments, lettuce was cultured in realistic growing systems in combination with various use rates of P-BC-LDHs. Multiple vegetative growth indices among individual treatments were compared. Figure 2: Elemental composition of seedlings under different application rates of P-BC-LDHs. Different letters indicate statistically significant differences. NS indicates no significance. Figure 3: (**a**) Seeds germinated on day 5 under different concentrations of P-BC-LDHs. (**b**) Comparison of lettuce grown under control conditions and with different treatments of P-BC-LDHs. The shoot and root lengths of the 21-day-old lettuce plants are shown in Figure 4a. The treatments with P-BC-LDHs positively affected these growth attributes, enabling a gradual increase in total plant height compared to the untreated control. Specifically, lettuce grown under mixtures with more P-BC-LDHs showed a superior shoot growth performance, which was larger by a factor of approximately 1.1 compared to those with less P-BC-LDHs. Shoot height was lowest for plants from the untreated control group. However, there were no significant differences among lettuce planted with and without P-BC-LDHs (\(p>0.05\)). Following a similar trend, the presence of P-BC-LDHs was also beneficial to root elongation. Under untreated control conditions, the poorest root improvement was observed at 69.45 mm in length. In contrast, when the growing medium was amended with P-BC-LDHs, they had longer roots, especially those from T7 and T8, of which a significant enhancement of up to 45% was attained (\(p<0.05\)). For lettuce yield responses, all treatments acquired the ability to promote fresh biomass (Figure 4b). With fertilization, biomass production averaged from 2.035 g to 2.229 g, which was higher than that of vegetables from the untreated control group (1.946 g). Moreover, a reduction of at least 10% in dry weight values was seen when P-BC-LDHs were not used. However, the application of these materials did not significantly affect either fresh weight or dry matter accumulation (\(p>0.05\)). Although these favorable outcomes corresponded to a rise in P-BC-LDH dosages and the outstanding growth quality was more pronounced in plants from the last two highest composite intakes, there were no meaningful differences between samples from T7 and T8 (\(p>0.05\)). In this study, 2.5% (_w/w_) of P-BC-LDH supply was sufficient for the advancement of lettuce traits. The elemental analysis (Figure 4c) further highlights the effect of the dosing quantity of P-BC-LDHs on plant nutrient uptake. The assimilation of P-BC-LDHs in substrates resulted in an excellent phosphorus concentration within the plant tissues. In particular, a more significant influence on phosphorus uptake was observed in the treatments with higher dosages (T7 and T8), which increased by up to 21% and 27%, respectively, compared to the other treatments and controls. Simultaneously, a larger amount of magnesium (by a factor of approximately 1.1) was also detected for all the treated lettuce. This suggests that the resultant fertilizer could provide this agricultural growing media with more available nutrients for plants, and therefore contribute to satisfactory vegetable growth that is superior to those grown without P-BC-LDHs.