Advances in Applied Agricultural Sciences 03 (2015), 02: 20-34
Carbon and nitrogen mineralization in clay loam soil amended with different composts
Neila Saidi 1*, Samra Akef 1, Olfa Bouzaiane 1, Hamadi Kallali 1, Nadhira Ben Aissa 2, Fadhel M’Hiri 3, Naceur Jedidi 1 and James Downer 4
1 Laboratory of Treatment and Water Recycling Centre of Research and Water Technologies (CERTE) Technopark of Borj-Cedria Tunis Tunisia.
2 National Institute of Agriculture Sciences, Charle Nicole 1082 Tunis Tunisia.
3 International Center of Technology of the Environment Boulevard of the leader Yasser Arafet, Tunis 1080, Tunisia.
4 University of California Cooperative Extension 669 County Square Drive, Suite 100 Ventura, CA 93003-805, USA.
This study investigates the effects of different composts on chemical and biomass soil properties. This study also measures mineralization of nitrogen (N) and carbon (C) in soils amended with different organic residues including manure and composts. A laboratory incubation experiment was conducted to study the effect of different amendments such as C1: composted greenwaste (GW) C2: composted Posidonia oceanica mixed with poultry manure (70/30%; v/v); C3 compost green waste mixed with Posidonia oceanica (70/30%; v/v), C4: compost of municipal domestic solid wastes, on mineralization of N and C, EC, pH and microbial biomass in soil. Farmyard manure (F) was used as a control test. Eight weeks after incubation, the highest electric conductivity (EC), was recorded in soil amended with C3 (500 µS/cm) while the lowest value was recorded in the sample from the soil treated with C2 (316 µS/cm). The salt content of the green waste compost C1 (422 µS/cm) was not significantly different than soil amended with C2 (427 µS/cm). Organic matter in soil treated with C4 showed high potential mineralization of carbon and nitrogen compared to those observed in a soil (S) treated with manure. After eight weeks of incubation, carbon mineralization of the different organic residues expressed as mg C/kg dry matter (DM) exhibited the following order (values): Carbon mineralization of different soil applied organic residues ranked in the following order: S + F (463) > S + C3 (318) > S + C4 (286 ) > S + C1 (257) > S+C2 (233) > S (167). However; net N mineralization expressed as mg N/kg dry soil after 8 weeks of incubation has the following order: S + C4 (80) > S + C3 (71) > S + F (64) > S + C1 ( 57) > S+C2 (48) > S (47). Posidonia oceanicaassociated with green wastes increased carbon mineralization from 257 to 318 ppm C, N mineralization from 57 to 71 ppm N. However addition of Posidonia oceanica to the green vegetable pile reduced the biomass C from 667 to 498 mg/Kg DM and biomass N from 34.17 to 24.59 mg/Kg DM.The present study showed significant variation in the mineralization of nitrogen and carbon after addition of different types of organic wastes.
Keywords: Soil, Green wastes, Posidonia oceanica, Compost, Amendment, Mineralization, Biomass C and N