Field capacity regime

Figure 6.1. The fractional loading isotherms of Cu in a contaminated Israeli loessial soil at an initial (one hour) period and after 48 weeks. The soil was treated with increasing levels of metal nitrates and was incubated under the field capacity regime. Horizonal solid line represents the native content of Cu in the nonamended soil (Figure 6.1 - Figure 6.4, after Han and Banin, 2001. Reprinted from Commun Soil Sci Plant Anal, 32, Han F.X and Banin A.,The fractional loading isotherm of heavy metals in an arid-zone soil, pp 2700-2703, Copyright (2001), with permission from Taylor Francis)...

Following the initial fast retention, the slow redistribution of the added metals occurred over time. During one year of incubation under the field capacity regime, heavy metals were slowly transferred among solid-phase components as shown in Figs. 6.1-6.4. Added Cu and Ni were transferred from the EXC and CARB fractions into the ERO and OM fractions and Zn mainly into the ERO fraction. Chromium and Pb moved from the CARB fraction into the OM and ERO fractions, respectively. Cadmium redistributed from the EXC fraction into the CARB fraction. After one year of incubation under the field capacity regime, 65-100% of the added Cd was transferred to the CARB fraction. About 50% and 20% of the added Pb was redistributed to the CARB and ERO fractions, respectively. 

Native Pb in Israeli arid soils mainly resided in the CARB and the RES fractions in the loessial soil, and it resided in the RES and the RO fractions in the sandy soil. During incubation under the field capacity regime, added Pb was slowly transferred from the CARB fraction into the ERO fraction (Fig. 6.13). However, the majority of Pb still remained in the CARB fraction. 

Figure 6.20. Distribution of Mn in solid-phase fractions in Israeli soils. Soils were incubated at the field capacity regime...

Figure 7.6. Decreases in bioavailability (as NH4N03-extractable) of Cu, Ni and Zn in an Israeli loess soil receiving metal salts and incubated under field capacity regime for one year (data from Han and Banin, 1999)...

Distribution of Mn in solid-phase fractions in Israeli soils. Soils were incubated at the saturated paste regime (after Han and Banin, 1996. Reprinted from Soil Sci Soc Am J, 60, Han F.X., Banin A., Solid-phase manganese fractionation changes in saturated arid-zone soils Pathways and kinetics, p 1075, Copyright (1996), with permission from Soil Sci Soc Am). Distribution of Mn in solid-phase fractions in Israeli soils. Soils were incubated at the field capacity regime. 

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