Forms of Potassium and their Distribution under Prominent Cropping Systems of Chittoor District of Andhra Pradesh, India

An investigation was carried out to assess distribution of forms of potassium in soils and seven prominent cropping systems from Chittoor district of Andhra Pradesh viz., Groundnut + Redgram, Groundnut-Groundnut, Groundnut monocropping, Redgram monocropping, Sugarcane monocropping, Paddy-Groundnut and Bajra-Groundnut. The highest mean available K was recorded under groundnut + redgram intercropping system (126.41 mg kg⁻¹) in surface soils, while in sub-surface soils under groundnut monocropping system (89.32 mg kg), water soluble K in surface soils under bajra-groundnut cropping system (38.70 mg kg⁻¹), while in sub-surface soils under groundnut + redgram intercropping system (23.29 mg kg⁻¹), exchangeable K under groundnut monocropping system in surface soils (102.63 mg kg) and in sub surface soils (72.17 mg kg⁻¹), non-exchangeable K under paddy-groundnut cropping system (517.83 mg kg), while in sub-surface under bajra-groundnut cropping system (475.20 mg kg⁻¹). The mean lattice K and total K were under redgram monocropping system in surface soils (40313.16 mg kg⁻¹ and 40794 mg kg⁻¹, respectively), while in sub-surface soils under groundnut+redgram intercropping system (35802.72 mg kg⁻¹ and 36248 mg kg⁻¹, respectively).The different forms of potassium were positively and significantly correlated among themselves with eachother in soils of indicating dynamic equilibrium among different forms K.