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Spatio-Cliamtic Variability in Soil Physical Properties and Bioavailability of Potassium Under Different Land Use Systems

Salma Jabeen, Imran Haider Shamsi, Muhammad Faheem Adil and Qichun Zhang

The current study was conducted to determine the effects of climatic regimes on crop yield under different land use systems to explore the variations in soil nutrients bioavailability and climate on vegetation. Through this research we explored a piece of scientific information about the physical properties of soil. Soil physical properties and bioavailability of labile potassium were studied in relation to varying locations, land use systems and climatic regimes selected on the basis of difference in their temperature, precipitation and altitude in Pakistan. The 30 years (1980-2010) climatic trend analysis of the two regimes revealed significant changes that probably may have significant impact on the soil nutrients and subsequent production and farming practices. The soluble and extractable form of K+ was assessed through deionized water and ammonium acetate extraction and total form of elements was determined by acid digestion using nitric acid and hypchloric acid (HNO3 and HClO4) at 1:5 ratios. Soils of different land use systems were found neutral to alkaline in nature, except few forest and rangeland soils that were slightly acidic in nature. The pH and EC values in the two climatic regimes were like Cultivated land>rangeland>forestland. Of the two regimes, the highest pH and electrical conductivity (EC) values were found for Ghanche cultivated land (i.e. pH 8 and EC 0.9 dSm-1) in Gilgit Baltistan and lowest pH and EC values were for Astore forest land soil (i.e. pH 5.7) and Skardoo forest land soil (i.e. 0.024 dSm-1) respectively. Similarly in climatic regime II; Hazara division the highest pH and EC values were of haripur cultivated land soil (i.e. 7.8 and 0.56 dSm-1) and lowest value was for Abbottabad forest (i.e. 6.5 and 0.21 dSm-1). Moreover, cultivated lands of Hazara division found relatively higher EC values than that of Gilgit Baltistan division. Analysis of variance (ANOVA) at 0.5 level of significance revealed significant variations in various soil physical properties and the concentration of K+. The altitude data obtained also revealed the highest altitude in climatic regime-I for district Astore 2546 m and in Climatic regime-II for Abbottabad i.e. 1250 m. All these variations are attributed to the parent material, altitude, soil texture, pH and land use practices.