Carbon and nitrogen mineralization of sewage sludge compost in soils with a different initial pH
Journal
Soil Science and Plant Nutrition
Journal Volume
55
Journal Volume
55
Journal Issue
5
Journal Issue
5
Pages
715-724
Start Page
715
End Page
724
ISSN
17470765
Date Issued
2009-10
Author(s)
Huang, Cheng-Chieh
Abstract
Soil properties may affect the decomposition of added organic materials and inorganic nitrogen (N) production in agricultural soils. Three soils, Potu (Pu), Sankengtzu (Sk) and Erhlin (Eh) soils, mixed with sewage sludge compost (SSC) at application rates of 0 (control), 25, 75 and 150 Mg ha-1 were selected from Taiwan for incubation for 112 days. The aim of the present study was to examine the effects of SSC application rates on the carbon decomposition rate, N transformation and pH changes in three soils with different initial soil pH values (4.8-7.7). The results indicated that the highest peaks of the CO2 evolution rate occurred after 3 days of incubation, for all treatments. The Pu soil (pH 4.8) had a relatively low rate of CO2 evolution, total amounts of CO2 evolution and percentage of added organic C loss, all of which resulted from inhibition of microbial activity under low pH. For the Pu and Sk soils, the concentration of NH4+-N reached its peak after 7-14 days of incubation, which indicated that ammonification might have occurred in the two soils with low initial pH values. NO3--N rapidly accumulated in the first 7 days of incubation in the Eh soil (pH 7.7). The direction and extent of the soil pH changes were influenced by the N in the SSC and the initial soil pH. Ammonification of organic N in the SSC caused the soil pH to increase, whereas nitrification of mineralized N caused the soil pH to decline. Consequently, the initial soil pH greatly affected the rate of carbon decomposition, ammonification and nitrification of SSC.
Subjects
Carbon mineralization
Nitrogen mineralization
Sewage sludge compost
Soil initial pH
SDGs
Type
journal article