Manganese and Iron Solubility Changes as a Factor in Tile Drain Clogging: I. Observations During Flooding and Drying

Abstract

A field study of waterlogging and subsequent drying of the soil profile has shown that under irrigation culture in Imperial Valley reducing conditions became prevalent. Reducing conditions, as indicated by declining Eh values, became most favorable for dissolution of Mn and Fe near the soil surface. However, the concentrations of Mn2+ and Fe2+ were lowest near the surface, probably because of their leaching from this zone, and the shorter time of contact between soil solution and soil particles. The concentration of Fe2+ and Mn2+ were higher in the deeper horizons of the soil profile.In the plow layer, the reducing intensity increased, beginning 9 m away from the tile and reaching a maximum 18‐ to 23‐m from the tile drain. The Eh levels in the soil profile declined immediately after irrigation began and rose immediately after irrigation stopped indicating the importance of atmospheric oxygen to the oxidation‐reduction status and, therefore, to the solubility of iron and manganese compounds. Soluble organic carbon apparently was not related to the concentration of Mn2+ or Fe2+ in the soil solution even though the decomposition of soil organic matter is important in oxidation‐reduction reactions in the soil profile.

Soil Drainage as an Active Agent of Recent Soil Evolution: A Review

“…Concerning the so-called ochreous deposits, numerous authors hypothesized that they resulted from i) the solubilisation of Fe and Mn in the waterlogged horizons overlying the soil layer impeding natural drainage and ii) their transport in dissolved forms towards the drain where they oxidized and precipitated (Grass et al, 1973;Süsser and Schwertmann, 1983;Houot and Berthelin, 1992).…”

“…Particle losses were independent of the backfill material (Uusitalo et al, 2001). To conclude, if one part of the leached soil particles appears to be mobilized at the soil surface by the raindrop impact, the exact origin of the part coming from the subsoil is not completely determined.Concerning the so-called ochreous deposits, numerous authors hypothesized that they resulted from i) the solubilisation of Fe and Mn in the waterlogged horizons overlying the soil layer impeding natural drainage and ii) their transport in dissolved forms towards the drain where they oxidized and precipitated (Grass et al, 1973;Süsser and Schwertmann, 1983;Houot and Berthelin, 1992). …”

Ground-Based Magnetic Surveys as a New Technique to Locate Subsurface Drainage Pipes: A Case Study

“…As pipes fill with sediment or for some other reason start to fail (Ford, 1993;Grass, 1969;Grass et al, 1973;MacKenzie, 1962) new pipes are installed usually without removing the old system. Even if old system locations were known, it is neither practical nor economic to remove them.…”