TY - JOUR
T1 - Carbon and nitrogen mineralization in different upland soils of the subtropics treated with organic materials
AU - Khalil, M. I.
AU - Hossain, M. B.
AU - Schmidhalter, U.
N1 - Funding Information:
The Danish International Development Agency (DANIDA) and Ministry of Agriculture, Government of Bangladesh under its Soil Fertility and Fertilizers Management Project jointly funded this research. The technical assistance of Mr M.A. Wahab Mia, Ms Kamrun Nahar and Mr Jahangir Alam is gratefully acknowledged. Thanks to the Alexander von Humboldt Foundation, Germany for awarding a fellowship that facilitated the writing up the results of this study by the senior author.
PY - 2005/8
Y1 - 2005/8
N2 - Use and management of organic waste/residues is currently an important global issue for attaining sustainability in agricultural production. However, knowledge about the decomposition characteristics and nutrient release pattern of added organic materials in subtropical soils and their interaction with inherent soil properties are lacking. Thus, laboratory incubation studies were carried out under aerobic conditions with crop residues and chicken manure (1%) applied to six contrasting soils. In all cases, CO2-C effluxes peaked by day 9 and the active C release phase persisted until day 25, indicating that priming effects might have occurred. The high pH and non-calcareous soils had higher CO2 effluxes than the acidic soils. The relative loss of added C differed between soils and its magnitude depended on the decomposable characteristics of the added organic materials, with chicken manure>mungbean residue>wheat residue. Rapid ammonification with presumed immobilization occurred up to day 15. Thereafter, NH4+ oxidation took place in the high pH and non-calcareous soils, with chicken manure exhibiting the greatest nitrification. By contrast, the acidic soils predominantly accumulated NH4+, thereby showing higher net N mineralization. In the acidic soils, nitrification was either small or stable, with the process being limited by the addition of organic materials with a high C/N ratio. Some disappearances of NO3- also indicated that N immobilization and/or denitrification had taken place. As such, the decomposition rate constant (k) correlated well either with pH alone (R 2=0.59***) or coupled with C/N ratio (R 2=0.61***) of the organic materials. The net N mineralization and nitrification showed a similar trend (R2=0.26-0. 42*), although these processes were mostly regulated by the different soil factors. Our results reveal that the parameters pH and C/N ratio of organic materials should be included in equations to calculate the quality of added organic matter. Our newly proposed equations, incorporated as the organic matter quality index (OMQI), can predict k, net N mineralization and nitrification in different soil types under aerobic conditions, and it could be further improved by also considering inherent soil factors.
AB - Use and management of organic waste/residues is currently an important global issue for attaining sustainability in agricultural production. However, knowledge about the decomposition characteristics and nutrient release pattern of added organic materials in subtropical soils and their interaction with inherent soil properties are lacking. Thus, laboratory incubation studies were carried out under aerobic conditions with crop residues and chicken manure (1%) applied to six contrasting soils. In all cases, CO2-C effluxes peaked by day 9 and the active C release phase persisted until day 25, indicating that priming effects might have occurred. The high pH and non-calcareous soils had higher CO2 effluxes than the acidic soils. The relative loss of added C differed between soils and its magnitude depended on the decomposable characteristics of the added organic materials, with chicken manure>mungbean residue>wheat residue. Rapid ammonification with presumed immobilization occurred up to day 15. Thereafter, NH4+ oxidation took place in the high pH and non-calcareous soils, with chicken manure exhibiting the greatest nitrification. By contrast, the acidic soils predominantly accumulated NH4+, thereby showing higher net N mineralization. In the acidic soils, nitrification was either small or stable, with the process being limited by the addition of organic materials with a high C/N ratio. Some disappearances of NO3- also indicated that N immobilization and/or denitrification had taken place. As such, the decomposition rate constant (k) correlated well either with pH alone (R 2=0.59***) or coupled with C/N ratio (R 2=0.61***) of the organic materials. The net N mineralization and nitrification showed a similar trend (R2=0.26-0. 42*), although these processes were mostly regulated by the different soil factors. Our results reveal that the parameters pH and C/N ratio of organic materials should be included in equations to calculate the quality of added organic matter. Our newly proposed equations, incorporated as the organic matter quality index (OMQI), can predict k, net N mineralization and nitrification in different soil types under aerobic conditions, and it could be further improved by also considering inherent soil factors.
KW - C and N turnover
KW - OMQI
KW - Organic materials
KW - Subtropics
KW - Upland soils
UR - http://www.scopus.com/inward/record.url?scp=20344366567&partnerID=8YFLogxK
U2 - 10.1016/j.soilbio.2005.01.014
DO - 10.1016/j.soilbio.2005.01.014
M3 - Article
AN - SCOPUS:20344366567
SN - 0038-0717
VL - 37
SP - 1507
EP - 1518
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
IS - 8
ER -