Geoinformatics Support for Information Based Agriculture: a Case Study of Arid Tract of Punjab

Information based agriculture (IBA) includes matching of agronomic practices with soil and water characteristics and their spatial variability for enhancing productivity. An attempt was made to derive agriculture management zones based on soil and water characteristics for sustainable agricultural production in Mansa district (Punjab, India). Based on physiographic analysis and semi detailed soil survey of the area was undertaken through interpretation of IRS 1C LISS-III data and the soil map was finalized on 1:50,000 scale. Georeferenced surface (0–0.15 m) soil samples from 208 sites were collected from dominant soils of the district developed on various physiographic units to study the spatial distribution of available phosphorus (P) and potassium (K). Georeferenced ground water samples from 271 working tube wells were also collected to assess the quality of ground water for irrigation purposes. A spherical model was fit using least squares in the geostatistical analysis and used to krig the entire study area for soil nutrient status and ground water quality parameters. Interpolation by kriging produced digital maps showing the geographical distribution of soil (P and K) and water parameters (EC and RSC). Based on EC and RSC limits, ground water quality map was also generated. The krigged P and K maps indicated generally lower content of these nutrients in the south and south west of the study area as the soils are relatively coarser in texture and the quality of ground water is poor. Soil and ground water quality maps were integrated using Arc Info GIS to generate map showing varying degree (high, moderate and low) and type (salinity, sodicity and both) of sensitivity to secondary salinization indicating fine textured soils as highly sensitive and medium textured soils as moderately sensitive to development of secondary salinization. The resultant map was further integrated with map for available P and K to derive agricultural management zones depicting the combined influence of soil texture and ground water quality on soil nutrients (P and K). the derived map indicated that coarse textured soils irrigated by highly saline water had low nutrient contents as compared with their content in fine textured soils irrigated by good waters.