What to read after Crop Production in Acidic Environment?

Soil acidity is one of the major problems for crop production in many parts of the world. Poor crop productivity and soil fertility in acid soils are mainly due to a combination of aluminum and manganese toxicities and nutrient deficiencies (mainly deficiencies in P, Ca, Mg and K). Among these problems, aluminum toxicity is one of the major factors limiting crop production in acidic soils. Aluminum, the third most abundant metal in the earth's crust, poses a serious threat to crop productivity in acidic soils. It covers approximately 40 per cent area of the earth's arable land (Ma et al. 2011). Aluminum exists in nature as mononuclear, polynuclear and also as low molecular weight complexes. However, mononuclear is considered as highly toxic as compared to other forms (Taylor 1991, Kinraide 1993). When the soil pH drops below 5.0, aluminum is solubilized as the phytotoxic Al3+ species from non-toxic aluminum silicates and oxides (Lindsay 1979). The mobility of aluminum increases sharply with the reduction in the availability of exchangeable cations such as Ca2+, Mg2+ and K+ (Parker et al. 1989). The high mobility of aluminum is seen in Kaolinite rich soils at pH levels as high as 5.5 (Alam and Adams 1979, Foy 1974. Roy et al. 1988). The toxicity will be acute at pH 4.1 in soils than at pH 4.5. However, in nutrient solutions, aluminum toxicity is more severe at pH 4.5 than at 4.0 due to the formation of A1(OH)2+ ions, which are more toxic than A13+ itself (Moore 1974).