Impact of Paper Mill Effluent on Groundnut Root Nodulation and Soil Microorganisms for Inclusion of Compost

A Field experiment was conducted at Mondippatti village in Tiruchirappalli district of Tamil Nadu to study the effect of paper mill effluent irrigation with or without compost application on root growth, biological properties and soil nutrient status in Alfisol with groundnut as the test crop. The results revealed that the application of paper mill effluent along with compost favourably increased the soil nutrient status during the crop period. The highest concentrations of available nutrients viz., nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron and zinc in the surface layer were 309.4 kg/ha, 14.2 kg/ha, 211.9 kg/ha, 64.9 meq/100g, 32.5 meq/100g, 38.8 mg/kg,11.4 mg/kg and 0.8 mg/kg, respectively in 75% paper mill effluent and press mud compost applications. Similarly, the use of paper mill effluent along with compost has a positive impact on soil microbial properties and highest population of bacteria was observed in 50% paper mill effluent and press mud application was 9.79 CFU (x106/g) followed by 100% paper mill effluent and press mud application (7.63 CFU (x106/g). While fungi and actinomycetes populations are higher in 75% paper mill effluent and farm yard manure application which were 5.64 CFU (x104/g) and 5.62 CFU (x104/g) respectively. The highest number of nodules was noticed in 100% paper mill effluent with press mud at 5 t/ha (45 numbers) followed by 75% paper mill effluent with press mud at 5 t/ha (42 numbers). From the study, it was concluded that the application of paper mill effluent with compost was found to be a promising source for soil fertility and root growth in groundnut.