Influence of magnesium on aggregate stability in sodic red-brown earths

摘要: Studies on sodium clay separated from a red-brown earth demonstrated that higher concentrations of magnesium salts than calcium were required for flocculation. Statistical analysis the data range earths showed dispersion clays soils with an SAR1:5 >3 increased as Ca/Mg ratio 1:5 soil-water extracts decreased below unity. The hydraulic conductivity columns <2 mm surface and subsurface samples one was significantly reduced when ratios in percolating solutions unity only SAR above 3 TCC (total cation concentration) values less predicted flocculation values. When solution exceeded values, not affected by either or ratio. If structural problems sodic containing high levels exchangeable (e.g. Ca/ Mg < 1) are to be minimized, it is necessary maintain electrolyte level threshold value particular soil. In specific effect so small magnesium-dominant additional gypsum application 1 t ha-1 10 cm soil should sufficient.