Dr. Manjunatha HebbaraS. M. KAMBLE2018-02-222018-02-222014-12http://krishikosh.egranth.ac.in/handle/1/5810041203A field experiment was conducted at Ugar-Khurd, Athani taluk, Belagavi, Karnataka to study the effect of different periods of spentwash application (5-10, 10-15, 15-20 and > 20 years) on soil properties and performance of sugarcane crop in a Vertisol of Northern Dry Zone (Zone-III) of Karnataka. The results revealed that application of spentwash for 5 to 10 years was superior with respect to growth, yield and quality parameters of sugarcane like millable cane height, diameter of cane, number of internodes, internodal length, number of millable canes, single cane weight, dry matter content, yield brix per cent, pol per cent and purity per cent. The crop could not be established in the plot which received spentwash for >20 years. The uptake of nitrogen, phosphorus and potassium was higher in the treatment that was irrigated with spentwash for 5 to 10 years which decreased with increased periods of spentwash application. The sodium uptake by sugarcane increased due to continuous application of spentwash and recorded the highest uptake under 15 to 20 years of spentwash application. Long-term application significantly reduced the soil bulk density, erosion index, dispersion index and increased maximum water holding capacity, aggregate stability and infiltration rate. The EC and ESP values increased with increased periods of spentwash application recording the highest values under >20 years of spentwash application. The salinity value increased beyond the threshold for sugarcane crop. The available nutrient status, CEC, base saturation, ESP and CaCO3 content in soil was higher in the plots irrigated with spentwash for >20 years. The higher soil bacteria, fungi and actinomycetes population was found in the treatment that received spentwash for 10 to 15 years, which decreased at > 20 years of spentwash application.enThesis