Dr. P. MUNIRATHNAMSWAMI CHAITANYA, T2018-07-192018-07-192016http://krishikosh.egranth.ac.in/handle/1/5810060959D5373A field experiment was conducted during post rainy season (maghi) of2015- 16 at RARS, Nandyal of Acharya N.G. Ranga Agricultural University tostudy the “Assessment of production potential of white sorghum under high input management in vertisols”. The experiment was laid out in split plot design with three replications and treatment combinations of three irrigation levels and four nitrogen levels making twelve treatments (three irrigation levels viz., no irrigation (rainfed), one irrigation and two irrigations were tested against four nitrogen levels viz., 90, 120, 150 and 180 kg N ha-1. Recommended dose of phosphorus (40 kg ha-1) and potassium (30 kg ha-1) was applied uniformly to all the treatments. The salient findings of the investigation are summarized below. The soil of experimental site was clay in texture and it was moderately alkaline in reaction with a pH of 8.6; EC of 0.15 dSm-1, low in organic carbon (0.57%), low in available nitrogen (146.2 kg ha-1), medium in available phosphorus (33.2 kg P2O5 ha-1) and high in available potassium (395.9 K2O kg ha-1). The growth parameters like plant height, number of green leaves per plant and dry matter production were higher with two irrigations and lower values obtained with no irrigation. Application of 180 kg N ha-1 produced taller plants and shorter plants were produced with 90 kg N ha-1. Number of green leaves per plant and dry matter production were higher with application of 180 kg N ha-1and with 90 kg N ha-1resulted in lower values of these parameters. xvi Days to 50 per cent flowering was maximum with no irrigation while the minimum number of days to 50 per cent flowering was observed with two irrigations which was comparable with one irrigation. As regards the nitrogen levels, number of days taken to 50 per cent flowering, application of 180 kg N ha-1 resulted in early flowering followed by 150 kg N ha-1. Whereas delayed flowering was observed with 90 kg N ha-1 which was comparable with 120 kg N ha-1. The yield components viz.,number of grains per panicle, grain weight per panicle, grain and stover yields were significantly higher with two irrigations which were comparable with one irrigation, while significantly lower values for all these components were recorded with no irrigation.1000 grain weight did not differ significantly with irrigation levels. Significantly higher number of grains per panicle, grain weight per panicle, 1000 grain weight, grain and stover yields were higher with 180 kg N ha-1and comparable with 150kg N ha-1. Lower values of these components were recorded with 90 kg N ha-1. With regard to interaction significantly higher grain yield was produced with two irrigations at 180 kg N ha-1 but it was on par with two irrigations at 150 kg N ha-1 while lower grain yield was produced with no irrigation at 90 kg N ha-1 which was on par with no irrigation at 120 kg N ha-1. Higher stover yield was produced with two irrigations at 180 kg N ha-1 but was on par with two irrigations at 150 and 120 kg N ha-1 and lower stover yield was produced with no irrigation at 90 kg N ha-1 which was on par with no irrigation at 120, 150 and 180 and also comparable with one irrigation at 90 and 120 kg N ha-1. Harvest index was higher with one irrigation compared to no irrigation and two irrigations. Significantly higher harvest index was obtained with 150 kg N ha- 1 than 120 and 90 kg N ha-1.With regard to interaction, two irrigations recorded higher harvest index at 150 kg N ha-1 which was on par with two irrigations at 180 kg N ha-1and one irrigation at 90, 120, 150 and 180 kg N ha-1while the lower values were recorded with no irrigation at 90 and 120 kg N ha-1 which were on par with each other. With regard to post harvest soil available nutrients, no irrigation recorded significantly higher post harvest soil available nitrogen, phosphorus and potassium compared to two irrigations while lower values were recorded by two irrigations. Among different levels of nitrogen, higher values of soil nutrients were recorded with 90 kg N ha-1 except nitrogen which increased with increased nitrogen levels. Lower phosphorus and potassium were recorded with 180 kg Nha-1, whereas lower available nitrogen was recorded with 90 kg N ha-1. Maximum nutrient uptake of nitrogen, phosphorus and potassium in grain and stover was recorded with two irrigations, while minimum values were obtained with no irrigation.With regard to nitrogen levels, increased nutrient uptake of nitrogen, phosphorus and potassium in grain and stover was observed with 180 kg Nha-1 which was significantly superior over 90 kg Nha-1. xvii Gross returns, net returns and B:C ratio of sorghum were influenced by irrigation levels and nitrogen levels. Net returns and B:C ratio were maximum with one irrigation, while gross returns were higher with two irrigations and minimum values of gross returns, net returns and B:C ratio were observed with no irrigation. Higher gross returns and net returns were produced with the application of 180 kg N ha-1 compared to lower levels but the net returns were comparable with 150 kg N ha- 1. Higher B:C ratio was produced with 150 kg N ha-1 which was comparablewith180 kg N ha-1. Among irrigation levels, one irrigation was better compared to other levels. As regards nitrogen levels, higher economic returns were obtained with 150 kg N ha- 1. Hence, white sorghum can be grown successfully in vertisols with one irrigation at 150 kg N ha-1for getting higher yields and returns.en-USnullThesis