Farm-scale Mapping of Soil Phosphorus and Potassium Fractions Using Geostatistical Technique

Phosphorus (P) and potassium (K) are two major nutrients for agricultural productivity sustainability. The spatial variability maps of soil phosphorus content in surfacesoils collected through grid sampling technique were developed using geo-spatial technology Indian Council Agricultural Research-Indian Research Institute (ICAR-IARI) farm, New Delhi, India. Soil available P (NaHCO3-P) P-fractions such as NaOH extractable-P(NaOH-P), citrate-bicarbonate extractable (CB-P), citrate-bicarbonate-dithionite extractable-P(CBD-P) HCl extractable-P (HCl-P) sequential fractionation techniques K fractions(available-K non-exchangeable-K) estimated. In geostatistical technique, exploratory data analysis semivariogram & fractions conducted ordinary kriging was used interpolation mapping. On average basis, among the P-fractions, Ca-boundphosphorus had highest value followed by non-occluded Fe- Al-bound-P (i.e. NaOH-P)and occluded-P within iron oxide hydrous CBD-P). farmranged from 43.9 to 839.3 mg kg-1 non-exchangeable-K found be high veryhigh level (820-1921 kg-1). Among fractions, Ca-bound showed first order polynomial surface trend, which removed before interpolation. Semivariogram P- K-fractions at IARI farm indicated effective range dependency. Prediction K- semiarid thorough superior log-normal kriging. map based fertilizer recommendation management practices cropping systems farmarecrucial precision nutrient sustainable agriculture.