Acid Soil Amelioration with Paper Mill Sludge and its Impacts on Biomass, Grain Yield, Water Footprints and Nutrient Uptake by Rainfed Groundnut

Acid soils affect nutrient uptake, water footprints and nitrogen use efficiency directly or indirectly by influencing the availability of plant nutrients, crop growth, biomass and yield. Thus, the maintenance and management of acid soils are very much important to obtain higher productivity and in turn to reduce water footprint of the crop on sustainable basis. In this study, possibility of using low cost liming materials like paper mill sludge (PMS) to ameliorate acid soil was investigated and its impacts on productivity, farm level water footprint and nutrient uptake of groundnut were assessed under tropical monsoon climate of eastern India. The PMS used in this study contained 32.5% calcium carbonate which was applied at different rates viz., 20, 30, 40, 50 and 60% of lime requirements (LR), 4–5 weeks before sowing of the crop and results were compared with the control (no lime treatment, 0% LR). The PMS was found to be useful to enhance the soil pH, nutrient uptake, biomass, leaf area and yield and reduced water footprints of groundnut production significantly when it was applied up to 50% LR. However, no significant differences on these parameters were observed when PMS was applied above 50% LR.