Acidified biochar and it's potential to ameliorate saline-sodic lowland rice soils in Balayan, Batangas, Philippines

In a previous study, lowland rice soils in Balayan, Batangas [Philippines] were generally salt-affected. Numerous studies have reported that the application of biochar improved the soil's condition. Amelioration of saline-sodic soil using modified biochar is effectively new method that requires thorough research. To answer the objective, three studies were conducted to characterize the physicochemical properties, evaluate the potential of acidified biochar, and assess the farmer's perception of saline-sodic soil. The physicochemical properties of acidified biochar generally reduced after acid modification. The FESEM-EDS revealed no apparent changes in surface morphology caused by acid modification, but C, Si, O, N, P, K, Ca, Mg, S, Na, Cl, Fe, Al, and Ti were all determined. The BET showed that acid modification and pulverization caused a decrease in surface area, pore volume, and pore radius. In ATR-FTIR, additional peaks of carbonyl (C=O Stretch) and alkaline (C-H Bend) were determined on the acidified biochar. No significant improvement in crystallization was determined in the XRD. In the incubation experiment, the application of acidified biochar at 150% RAR significantly reduced the soil pH, increased the WSA at 100% PAR (T2), and increased WHC (t3 at 150% PAR). However, ESC, ESP, and SAR did not reduce after 45 days of incubation. The OM, content improved with the use of acidified biochar at 150% RAR. However, no significant differences were determined on other soil parameters. Overall, the application of acidified in biochar had a limited effect in ameliorating some of the problems in saline-sodic soil. The perceptions of rice farmers with saline-sodic lowland rice in soils in Navotas, Balayan, Batangas, determined through KII and FGD and analyzed the thematic analysis and CLD, showed that the perceived major cause of saline-sodic soil was saltwater intrusion. The major effects were impeded growth and lower harvest. This months of June, July and August, and vegetative and flowering stages, were determined to be the most prone to saline-sodic soil. For their strategies, irrigating with freshwater and planting salt-tolerant varieties are practiced. The expansion of saline-sodic soil was perceived to be the major challenge. In general, rice farmers perceived that saline-sodic lowland rice soil is a worsening problem.