Abstract
EFFECT OF LAND USE ON MICROBIAL BIOMASS, CARBON AND NITROGEN FROM FALLOW ON SANDY-CLAY OF SAVANNA, CONGO
Goma-Tchimbakala Joseph*, Lebonguy Augustin Aimé and Dzoulou Zama Lorianne
ABSTRACT
The study was carried out at the Agricongo center situated at seventeen kilometers from Brazzaville. The aim of the present study was to assessment the effects of land use on chemical and microbiological characteristics of soil. Seven sites were chosen in the study area : S1 grass fallow with legume grown; S2 grass fallow; S3 fallow with cowpea residues incorporated into soil; S4 soybean cultivation; S5 grass fallow (7-year-old); S6 coffee plantation; S7 Orchard, in which composite soil samples were taken at 0-10 and 10-20 cm depth for determination of pH, total organic carbon, total nitrogen and microbial biomass. The results showed that pH was different between the depth and between the sites. highest total organic carbon content was recorded in site 1 (16.7%) and site S2 (12.4%) of 0-10 and 10-20 cm respectively. While lowest content was recorded in site 6 in 0-10 cm depth and in Site 7 in 10-20 cm depth. In 0-10 cm depth, total nitrogen was higher in S1 and lower total nitrogen was in S7. Total nitrogen recorded in 10-20 cm was higher in S6 and lower in S7. Microbial biomass carbon of 0-10 cm was higher in S1 with 309.5 ?g / g soil and lower in S7 with 147.3 ?g/g soil. In 10-20 cm depth, microbial biomass carbon was 271,93 ?g/g soil in S7 and 109.3 ?g/g soil in S3 and S4. Microbial biomass nitrogen was ranged between 6.48 and 69.12 ?g /g soil and between 9.36 to 55.6 ?g /g soil respectively in0-10 and 10-20cm depth. The results obtained in the present study showed that land use had high impact on the characteristics of soil mainly on pH, organic matter and microbial biomass.
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