Information on loss of carbon in form of CO2
from the soil in response to soil amendments is wanting in tropical dryland
agroecosystems. This two year study of soil CO2 in tropical dryland
agroecosystem supporting rice-barley-fallow annual sequence involved addition
of equivalent amount of N through chemical fertilizer and three organic inputs
(high quality resource, low quality resource, and high and low quality resource
combined) besides control. A marked seasonal variation was noticed in CO2 flux
in all treatments, with higher levels obtained during rice crop (warm-wet
period) and considerably decreased flux during barley crop (cool dry, period).
CO2 flux differed in various treatments. In terms of annual mean,
low quality input showed 92% greater CO2 flux relative to control
(127 mg CO2 m-2 hr-1) whereas combined input
showed 75% increase. However, the CO2 flux expressed on the basis of
per unit exogenous carbon added was ca.100 times higher in case of fertilizer
relative to low quality input application (ca. 11 mg CO2 g-1
C hr-1) (cf. High quality input, 3 times, and combined input 1.5
times greater). These results show that CO2 flux is more related to
C input than the input of N.
Author: N. Ghoshal, S. Singh, and K.P. Singh (n dot ghoshal at yahoo dot co dot in)
Filesize: 41.00 Kb