Characterization of soils under different periods of eucalyptus cultivation and restoration in Malur and Hoskotetaluks of Karnataka, India

Considerable area under eucalyptus plantation in the form of farm forestry exists in Malur and Hoskotetaluks of Karnataka, India. But in the recent years, Government of Karnataka has checked the spread of eucalyptus and farmers are gradually converting their eucalyptus plantations into agricultural lands. This study was aimed to evaluate soils of eucalyptus during growing and after restoration and its adjacent croplands having no history of eucalyptus cultivation in Taluks of Malur and Hosakote, Karnataka for physico-chemical properties and evaluated during the year 2019-2020 at College of Horticulture, Kolar. The results revealed that soils under 12, 24 and 48 years of eucalyptus cultivation when compared to soils after two, six and ten years of restoration and adjacent soils, showed significantly high bulk density (1.28 to 1.51 Mg/m3) and low water holding capacity (30.30 to 45.61%). These soils were more acidic in reaction (pH: 6.21 to 6.65) and contained significantly lower amounts of total soluble salts (EC: 0.04 to 0.07 dS/m), organic carbon (OC: 0.24 to 0.59%), available N, P2O5 and K2O (163.07 to 235.42, 26.03 to 47.23 and 112.89 to 168.55 Kg/ha, respectively), exchangeable Ca and Mg (1.70 to 2.75 and 0.80 to 1.32 cmol (p+)/Kg, respectively) and available S (5.60 to 7.09 ppm) but contained significantly high amounts of available Fe, Mn, Zn and Cu (13.52 to 29.74, 14.06 to 20.14, 1.44 to 2.06 and 1.16 to 1.74 ppm, respectively). Further, bulk density, acidity and available micronutrient cations of soils tends to increase with prolonging the cultivation period of eucalyptus while, reverse trend was observed with respect to water holding capacity, organic carbon and available macronutrients contents. On the other hand, restored plots showed significantly decreased acidity, bulk density and available micronutrient cations and increased water holding capacity and macronutrients contents with increasing the restoration period