Influence of Rice Husk Biochar and Lime in Reducing Phosphorus Application Rate in Acid Soil: A Field Trial with Maize

Abstract

Biochar has been suggested for application in acidic soils for increasing agricultural productivity, as it may result in the benefits of sustainable carbon offset into soils and of increasing soil fertility improvement. However, the role of biochar in enhancing nutrient bioavailability and plant performance is manifested through the complex interactions of biochar-soil-plant. Moreover, it is not yet known how a crop-residue-derived biochar would perform in acidic soil when applied with a reduced rate of lime and phosphorus. Here, we examined the performance of maize with different combinations of biochar, lime, and phosphorus (P) application rates under field conditions. Specifically, rice husk biochar (10 t ha−1) was applied with 75% of the required lime and three rates of phosphorus fertilizer (100%, 75%, and 50%). The results showed that incorporation of biochar and lime, irrespective of the rates of P application, significantly increased soil nutrient (nitrogen and P) availability, while aluminum (Al) and iron (Fe) concentrations in soil were reduced. Furthermore, when biochar was combined with a lower amount of lime (75% of the recommended amount) and half of the required P, maize production increased by 62.38% compared to the control. Similarly, nutrient uptake in plants increased significantly in the same treatment (e.g., P uptake increased by 231.88%). However, soil respiration (CO2 emission) increased with lime only and the combined application of lime with biochar compared to the control; these treatments resulted in a higher carbon loss, as CO2 from the soil (84.94% and 67.50% from only lime treatment (T2), and rice husk biochar (RHB) and lime with 50% triple superphosphate (TSP) (T5), respectively). Overall, our findings imply that biochar application may sustain productivity in acid soils even when lime and P fertilizer applications are made at a reduced rate.

Examining the Effect of Combined Biochar and Lime Rates on Selected Soil Physicochemical Properties of Acid Soils in Gimbi District, Western Ethiopia

“…Treatments amended with biochar and/or lime at (P < 0.05 demonstrated substantially lower BD compared to controls at both study sites. Similarly, a diferent study justifed that the application of biochar and/ or lime afected soil physical properties [40,72].…”

“…Furthermore, only 16.8 mg•kg −1 of the accessible phosphorous (available P) out of the total phosphorous of 138.01 mg•kg −1 was collected, and it had a low extractable p content. Phosphorous retention in biochar is a mechanism to provide vital indication for the efective management of P to boost crop production and sustain soil [29,40]. Tis might be caused by the biochar's high alkalinity.…”

“…Tis investigation made it clear that adding biochar and/or lime to the soil could enhance acid soil physical characteristics. Crop growth is encouraged on the treated soil with the addition of organic inputs and an improvement of the soil's physical attributes [32,40,73,74].…”

“…In this study, the application of lime and biochar resulted in a negative correlation between the carbon content and bulk density, and therefore, the improvement in soil porosity was investigated. Tis idea is confrmed by Mosharrof et al [40]. Te higher the total porosity of the soil, the better the soil's physical quality [32].…”

“…Various scholars have long argued on the reduction of soil acidity in uses of lime and biochar in the agricultural systems of developed nations [12,30,40,41]. Te benefts of this biochar are not widely recognized in tropical countries, especially in Western Ethiopia.…”