Impact of long term fertilization on some soil properties under rice-rice system in cauvery delta zone of Tamil Nadu

Results of twenty five years (1992–2017) of experimentation on rice-rice system revealed that treatment receiving continuous application of recommended NPK fertilizers (125–150 kg N, 50–60 kg P₂O₅, 50–60 kg K₂O/ha along with green manure, 12.5 t/ha of farm yard manure, 500 kg/ha of gypsum) significantly recorded significantly higher infiltration rate and water holding capacity in soil at the end of the 50^th rice crop. Soil chemical properties like pH, EC, organic C, available N, P and K exhibited significant changes due to various treatments imposed. The results suggest the need of integrated nutrient management practices to sustain rice productivity in the heavy soils of Cauvery Delta Zone.