Climate Policy Watcher

Soils Characteristics and Experimental Setup

Three different experimental sites along a North-South climate gradient were chosen to setup soil treatments. Soil classification textural composition and organic carbon content of the selected soils are shown in Table 4.1.

The effect of mature compost addition on soil carbon sequestration was evaluated by comparing the following field management during a 3-year experiment (2006-2008), using a monocolture of mais (Zea mais) as annual crop (see Chap. 3):

Table 4.1 Textural composition (%), bulk density, and TOC (g kg !) content of soils from field experiments

Field sites	Soil type	Sand	Silt	Clay	Bulk density	TOC
Torino	Typic Ustifluvent	36.9	56.2	6.9	1.50	11.5
Piacenza	Udifluventic Haplustept	17.9	47.1	35.0	1.30	17.2
Napoli	Vertic Haploxeralf	47.0	20.1	32.9	1.40	10.5

- Traditional (TRA): plowing at 35 cm depth, followed by surface harrowing with addition of mineral fertilizers.

- Minimum tillage (MIN): no plowing, with addition of mineral fertilizers.

- Green manure (GMAN): plowing at 30 cm depth, followed by surface harrowing. Leguminous crops were interlaced between two main annual cycles and used as green manure to totally or partially replace nitrogen fertilizer.

- Compost first rate (COM-1): same as the TRA plots but with the addition of an amount of mature compost corresponding to 2.7 ton ha-1 of OC.

- Compost second rate (COM-2): same as the TRA plots but with addition of an amount of mature compost corresponding to 5.4 ton ha-1 of OC.

Each management treatment was established on a 4 m x 4 m plot with four replicates, in a randomized block experiment.

The experiment based on the addition of the biomimetic catalyst was performed on 1m x 1 m field plots (n = 4) cultivated with wheat (Triticum Durum) for

3 years, with the following treatments:

- CAT: plowing at 35 cm depth, followed by surface harrowing with the addition of mineral fertilizer and 10 kg ha-1 of a biomimetic catalyst, the water-soluble iron-porphyrin (FeP). FeP was synthesized in the laboratory as meso-tetra (2,6-dichloro-3-sulfonatophenyl)porphyrinate of iron(III) chloride, Fe-(TDCPPS) Cl (Piccolo et al. 2005a).

- No-CAT: plowing at 35 cm depth followed by surface harrowing with the addition of mineral fertilizers.