Carbon storage of corn-based cropping systems in Isabela, Philippines
2016
Ocampo, N.P. | Zamora, O.B.
Total carbon (C) storage of three corn-based cropping systems: monocropping (M), legume in crop rotation (CR) and intercropping (I) of selected farmers in Isabela were evaluated. The total C stocks were estimated at fallow period and crop maturity. Carbon stocks at fallow period served as reference point to measure the change in C stocks in various C pools. Carbon stored in herbaceous vegetation of the monocropping system was significantly lower than the other two systems at fallow period. However, the reverse was true at crop maturity. Carbon stock in surface litter of the monocropping system at crop maturity was significantly lower than the legume in crop rotation and intercropping systems. Only the intercropping system increased C stored in surface litter, and this was attributed to high crop diversity at crop maturity. C stock stored in the roots decreased in legume in crop rotation but increased in the two other systems. Total soil organic carbon (SOC) at fallow and crop maturity were ranked as follows: M (26.51 and 25.18 Mg/ha) I (25.68 and 24.62 Mg/ha) CR (25.28 and 24.59 Mg/ha). In general, there was a decrease in total SOC in the three cropping systems. The decrease in the total SOC was highest in the monocropping system (-1.33 Mg/ha), which was 1.25 (-1.06 Mg/ha) and 1.94 (-0.69 Mg/ha) times higher than the decrease in intercropping and legume in crop rotation, respectively. There was an increase in total system C stocks in monocropping (3.67 Mg/ha), intercropping system (2.36 Mg/ha) and the legume in crop rotation system (0.72 Mg/ha). Both monocropping and intercropping systems stored higher C than legume in crop rotation. However, the lower decrease in SOC and less chemical fertilizer input in the intercropping system contributed to C sequestration and less C emission than the monocropping system.
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