We present results of a four year field study examining the changes in seasonal soil mineral nitrogen
(SMN) and soil pH from the application of an alkaline treated biosolid (ATB) in an acidic sandy loam soil.
Results of two management practices, annual ATB applications and a single application, and different
rates of ATB (0, 7, 14, 28 and 42 Mg ha1
) were also compared over the four year study period. Corn (Zea
mays L.) was used as the test crop throughout the study. Soil pH was effectively modified in all treatments
receiving ATB rates, compared to the control, under both management practices but best results were
achieved under annual ATB application. Soil cation exchange capacity was increased under annual ATB
applications, by 3 at the highest ATB. Compared to the control, soil nitrogen and pH displayed
significant changes under frequent additions with increasing rates of ATB. Our results indicate that a
single application at the highest ATB rate had a residual effect on soil pH but little impact on subsequent
SMN dynamics. Average soil mineral nitrogen (SMN) concentrations in the single application
management ranged from 8.3 to 9.3 mg kg1 in the final three years of the study but ranged from
8.5 to 12.1 mg kg1 under the annual application management. In contrast, annual applications of ATB at
rates 14 Mg ha1 increased seasonal SMN by 15–42% and soil pH by 1–1.5 pH units. Seasonal SMN
dynamics under different ATB rates and management practices were also examined using a soil nitrogen
ratio (SNR) and as an area under the seasonal SMN curve.
We present results of a four year field study examining the changes in seasonal soil mineral nitrogen(SMN) and soil pH from the application of an alkaline treated biosolid (ATB) in an acidic sandy loam soil.Results of two management practices, annual ATB applications and a single application, and differentrates of ATB (0, 7, 14, 28 and 42 Mg ha1) were also compared over the four year study period. Corn (Zeamays L.) was used as the test crop throughout the study. Soil pH was effectively modified in all treatmentsreceiving ATB rates, compared to the control, under both management practices but best results wereachieved under annual ATB application. Soil cation exchange capacity was increased under annual ATBapplications, by 3 at the highest ATB. Compared to the control, soil nitrogen and pH displayedsignificant changes under frequent additions with increasing rates of ATB. Our results indicate that asingle application at the highest ATB rate had a residual effect on soil pH but little impact on subsequentSMN dynamics. Average soil mineral nitrogen (SMN) concentrations in the single applicationmanagement ranged from 8.3 to 9.3 mg kg1 in the final three years of the study but ranged from8.5 to 12.1 mg kg1 under the annual application management. In contrast, annual applications of ATB atrates 14 Mg ha1 increased seasonal SMN by 15–42% and soil pH by 1–1.5 pH units. Seasonal SMNdynamics under different ATB rates and management practices were also examined using a soil nitrogenratio (SNR) and as an area under the seasonal SMN curve.
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