Ammoniacal and Nitrate Nitrogen Release Pattern from Biochar and Biochar Blended urea Fertilizers in Laterite Soil

Author: Kavya S.R., Rani B., Aparna B. and Gladis R.

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Abstract

Recognition of biochar as a potential nutrient carrier to delay the release of nutrients in soils by blending with fertilizers is growing. However, the rate of release of mineralizable nitrogen from the biochar blended fertilizers in different soils is poorly understood. Hence a laboratory incubation study was conducted for 12 months with paddy husk biochar, biochar-bentonite (1:1), urea, biochar blended with urea fertilizer in different ratios (1:0.5, 1:1, 1:2) and biochar bentonite (1:1) blended with urea fertilizer in different ratios (1:0.5, 1:1, 1:2) including an absolute control to elucidate the ammoniacal and nitrate nitrogen release pattern in laterite soil. Paddy husk biochar was produced by the method of slow pyrolysis and biochar blended urea fertilizers by the adsorbent process. Bentonite clay, was also mixed with biochar in 1:1 ratio and blended with urea fertilizer to evaluate its influence on the nitrogen release pattern. Release of ammoniacal nitrogen from soil added with urea fertilizer was fast with maximum release at 30 days (199.73 mg kg-1), followed by a sharp decline and maintaining a low value till the end of incubation, whereas the increase in ammoniacal nitrogen release was gradual and sustained reaching a maximum at 180 days (209.07 mg kg-1) for soil + biochar: urea in 1:1. Nitrate nitrogen also followed the same trend with the maximum release observed for biochar: urea in 1:1 on the 180th day (225.9 mg kg-1). Nitrate nitrogen release showed higher values compared to ammoniacal nitrogen throughout the incubation period for all the treatments. Blending of urea with biochar/ biochar-bentonite prolonged the period for maximum nutrient release. Among the blended fertilizers, the content of both ammoniacal and nitrate nitrogen were comparatively less for biochar –bentonite blended urea fertilizers.

Keywords

Biochar blended fertilizers, Ammoniacal and Nitrate Nitrogen, Laterite soil

Conclusion

A slow and steady release of nitrogen either as ammoniacal or nitrate was observed in laterite soil on blending biochar with urea compared to urea fertilizer alone. The rate of release of nitrate nitrogen was higher compared to ammoniacal nitrogen for all the treatments. Addition of bentonite to biochar resulted in slowing down of the release of both NH4+ -N and NO3-- N thus increasing the period of sustained release. The large surface area of biochar and abundant oxygen functional groups like carboxylic, hydroxyl and lactone groups on the surface of biochar- bentonite play a dominant role in adsorbing NH4+ and NO3−, ultimately reducing the N loss. Thus, biochar as a fertilizer carrier decelerates the release of nutrients into the soil and reduce fertilizer nutrient loss due to leaching, thereby increasing the efficiency of applied fertilizer.

References

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How to cite this article

Kavya S.R., Rani B., Aparna B. and Gladis R. (2023). Ammoniacal and Nitrate Nitrogen Release Pattern from Biochar and Biochar Blended urea Fertilizers in Laterite Soil. Biological Forum – An International Journal, 15(5): 805-810.