Raghavan Pillai, GRajasree, GKAU2020-11-132020-11-131999171594https://krishikosh.egranth.ac.in/handle/1/5810155022PhDAn investigation was carried out during 1995-96 and 1996-97 at the Instructional Farm attached to College of Agriculture, Vellayani to study the efficacy of different levels of N applications (200, 250 and 300 kg N ha") in different ratios of organic - chemical N substitutions (l : 1, 1:2 or 2: 1) at different frequencies (F I - full quantity of organic source as basal, F2 - organic source at basal and at 40th and 70th DAS, F3 - organic source as basal + fortnightly equal splits and chemical N source as basal + fortnightly intervals in equal splits in all the frequencies) of application. Two different organic sources ie. farm yard manure and poultry manure were used in two simultaneous experiments viz. Experiment I and 11. The experiments were separately and simultaneously laid out as confounded 33 design in 9 plot blocks with 2 replications, confounding LR2F in RI and LRF2 in R 11. Higher levels ofN nutrition was found to reduce days taken to flower in farm yard manure applied trial while sex ratio was narrowed at 90 DAS in poultry manure applied experiment. Higher jassid population was noticed at 60 DAS when higher levels ofN was supplied predominantly through organic source as farm yard manure. Fungal leaf spot infestation was higher with the application of200 kg N at 90 DAS and was also more with split applications of both farm yard manure and chemical N source at early stages of growth. Full basal application of poultry manure was found to promote the per hectare yield of fruits, fruit yield planr I and number of fruits planr I compared to its split applications. When highest level ofN (300 kg) was supplied through 2: 1 ratio of organic - chemical N substitution using poultry manure as organic source, it effectively increased the fruit yield and number of fruits plant". 2 Shelf life of fruits at room temperature was more when nutrient N was supplied through 2: 1 ratio of organic - chemical N substitution using farm yard manure or poultry manure as an organic source. When N level was increased beyond 200 kg, shelf life of fruits at room temperature slightly decreased even when it was predominantly supplied through organic source of farm yard manure or poultry manure. Similar trend was noticed at refiigeratory condition too. Nitrogen nutrition showed depressing effect on ascorbic acid or vitamin-C content of fruits in Experiment I. Iron content in fruits was more with the application of 200 or 300 kg N level in Experiment ll. When 300 kg N was applied through a major source of poultry manure (2: 1 ratio) it produced higher iron content in fruits. Higher nitrogen levels or nitrogen nutrition through 2: 1 ratio of substitution promoted the soil bacterial population in both Experiment I and II. Full basal application of farm yard manure or poultry manure favourably influenced the soil bacterial population. Nitrogen nutrition showed depressing effect on fungal population of soil in Experiment I while it stimulated the fungal growth in Experiment 11. Soil actinomycetes population was higher with 2: 1 substitution ratio using farm yard manure as organic source ofN. When farm yard manure or poultry manure as organic source was used in equal or higher proportion with chemical N source, it showed moderating effect on the soil acidity. Full basal application of farm yard manure also enhanced the soil pH from the acidic range and the organic carbon content. Application of higher levels ofN increased the net loss ofN, P and K of soil in both the Experiment I and H. Net loss ofN was higher with 1:2 ratio ofN substitution or few or more split applications of organic source (farm yard manure) in Experiment 1. Net loss of nutrients was moderated during the second year of field experimentation. Nitrogen 3 nutrition in 1:2 ratio of substitution enhanced the net loss ofN in Experiment H. Nitrogen nutrition through 2: 1 ratio ofN substitution or basal + 2 split doses of farm yard manure increased the net loss of P in soil. The net loss of K in soil was more when farm yard manure and chemical N sources were applied in 2: 1 or 1: 1 ratio of substitution. Net gain of K was observed in Experiment H, when chemical N source was substituted in higher proportion compared to poultry manure or when full dose of poultry manure was applied as basal dressing. Higher levels ofN application have resulted in negative net energy returns or energy loss in both the experiments. The 1: 1 or 1 :2 ratio ofN substitution caused higher net energy losses in Experiment I while split applications of poultry manure resulted in more energy loss in Experiment H. Total energy output was higher with full basal application of poultry manure in Experiment I. Energy ratios registered a negative value and was higher with low level ofN application in Experiment I and II. Higher gross returns were obtained when full quantity of poultry manure was applied as basal dose in Experiment 11. Application of300 kg N through 2: 1 ratio of organic- chemical N substitution registered higher gross returns in Experiment II. Net returns was higher when 200 kg N ha! was applied. Increasing N level beyond 200 kg was not economic in Experiment I using farm yard manure as organic source. When full quantity of poultry manure was applied completely as basal dose, higher net returns was obtained in Experiment H. Benefit-cost ratio decreased when N level was enhanced beyond 200 kg ha' in Experiment I. Higher benefit - cost ratio was recorded when poultry manure was applied in full dose as basal dressing. Study revealed the favourable influence of organic sources; farm yard manure and poultry manure on fruit quality, shelf life and soil properties. The suitability of poultry manure as organic source for vegetable cultivation was also established by this study.EnglishThesis