http://www.erepo.iihr.ernet.in/handle/123456789/513 Wed, 15 May 2013 16:51:15 GMT 2013-05-15T16:51:15Z http://www.erepo.iihr.ernet.in/handle/123456789/520 Title: Soil and nutrient management studies in Coleus vettiveroides. Jacob Authors: B, Mamatha Abstract: Application of 100:50:50 NPK kg ha-1 recorded significantly higher plant growth (50.86 cm), biomass accumulation (32.75 t ha-1), and nutrient uptake (uptake of 50.60 kg N,7.21 kg P,126.04 kg K ha-1) of C. vettiveroides at 116 days after planting (DAP). C. vettiveroides plant grown in 18 inch diameter with 30 inch length PVC column produced significantly higher total root yield (315.2 g plant-1) and biomass accumulation (3597.2 g plant-1) at 121 DAP. Growth media comprising of sand and soil mixed in equal proportion (100 kg) added with 0.5 kg Farm Yard Manure (FYM) recorded significantly higher biomass accumulation (728.34 g plant-1 and 1653 g plant-1) of C. vettiveroides in cement pots and PVC column respectively at 135 DAP. Application of FYM (282.80 g plant-1) or inorganic fertilizer (312.73 g plant-1) along with bio-fertilizer recorded higher biomass accumulation of C. vettiveroides as compared with sole application of FYM (210.49 g plant-1) or inorganic fertilizer (261.56 g plant-1) at 130 DAP. Significantly higher root yield (3.16 t ha-1), biomass accumulation (49.66 t ha-1) and nutrient uptake (uptake of 50.13 kg N, 7.75 kg P, 119.11 kg K ha-1) of C. vettiveroides recorded with application of recommended FYM (10 t ha-1) + recommended NPK (100:50:50 NPK kg ha-1) at 140 DAP. Application of Mukuna mulch 10 t ha-1 recorded significantly higher plant growth (51.74 cm) and application of FYM mulch 10 t ha-1 recorded higher biomass accumulation (33.37 t ha-1) and nutrient uptake (uptake of 49.30 kg N, 9.41 kg P, 148.74 kg K ha-1) of C. vettiveroides at 139 DAP. The different chemical constituents identified in oil of root of C. vettiveroides are hydrocarbons (ß-Himachalene, etc.,), oxygenated compounds like alcohols (Vellerdiol, Isothujol, etc.,), aldehydes (ß-Cyclocitral, etc.,), esters (Sabinyl acetate, etc.,), ketones (ß-Ionone, Traseolide etc.,). Thu, 01 Jan 2009 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/520 2009-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/519 Title: Persistence and mobility of paclobutrazol in soil Authors: L, Shalini Abstract: A field experiment was conducted at IIHR, Hessaraghatta, Bangalore, to study the persistence and mobility of paclobutrazol, a predominantly soil applied plant growth regulator to counter alternate bearing in mango following its application to mango tree basins at the rate of 5 and 10 g as per hectare. Soil, water and mango samples from Konkan region of Maharashtra were also collected in order to assess the extent of paclobutrazol residue contamination in these samples, as this area is the largest consumer of paclobutrazol in India. Sample were collected from both conventional soil cultivated orchards and laterite rock cultivations. The study indicated that paclobutrazol persisted at all soil depths for at least 150 days and reduced to below detectable limit at 210 days. It persisted at the surface (0-15 cm) with half lives of 30.7 and 29.7 days from the lower and higher treatment concentrations respectively. It was also seen that paclobutrazol moved quickly down the soil to reach up to or beyond 60 cm. soon after its application. The residues of paclobutrazol in the conventional soil cultivated mango orchards located at Konkan region of Maharashtra ranged below detectable limit to traces. No detectable residues of paclobutrazol were found in soils from laterite rock cultivated mango orchard from the same region irrespective of the number of years for which paclobutrazol applications had been made. The paclobutrazol residues were either below detectable limit or present in traces in mango whole fruits collected from either type of orchards at harvest, notwithstanding the frequency of its application in the orchard. Water samples collected at the time of fruit harvest from open wells located orchards did not contain detectable residues of paclobutrazol. Thu, 01 Jan 2004 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/519 2004-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/518 Title: Studies on persistence of hexaconazole in selected soils of Karnataka Authors: Harish Kumar Dubey Abstract: The study was taken up to determine the persistence and dissipation pattern of a commonly used fungicide Hexaconazole in two major soils of India differing widely in their physical and chemical properties. The two siols types were black clay soil from National Bureau of Soil Survey & Land Use Planning (NBSS & LUP), regional station, Bellary, Karnataka and loamy sand soil from IIHR, Hessaraghatta, Bangalore. Persistence degradation of Hexaconazole in soils was determined by adding 10 ppm of the toxicant to both the soil and incubating them under different soil moisture regimes. The degradation reaction rate constants “K” and half life values (t1/2) for both the soils were computed from the amount of fungicide remaining in soils at different periods following periodic residue analysis. The salient features of the investigation are summarized below: The two different soils collected from different locations represented fairly wide range of variation in soil characteristics such as textural make up, pH, organic matter content, CEC etc.,(loamy sand Hessaraghatta soil:Haplustalf and black clay Bellary soil: Typic chromustents) were used for the study. The organic matter content was fairly high in black clay Bellary soil, while it was moderately low in loamy sand Hessaraghatta soil. There were similar differences in the other characterstic such as clay content, pH and CEC also. The recovery analysis of the fungicide residue in soils indicated that the recovery percentages were fairly high exceeding 85% indicating the analytical technique with modification was good. There was a marked difference in the persistence hexaconazole in both the soil type. The degradation pattern of hexaconazole residues indicated a close correspondence to first order exponential degradation kinetics in soils and largely influenced by soil moisture. Increased degradation was observed with increased moisture content from air dry condition to submerged condition however there was a faster rate of degradation in 50 percentage field capacity soil moisture condition. Higher persistence of hexaconazole was noticed in black clay Bellary soil than in loamy sand Hessaraghatta soil. In general, the persistence of hexaconazole residues was high but persistence was influenced by moisture level. The half- life period (t1/2) of hexaconazole in black clay was found to 55.00 to 80.58 days at different soil moisture regimes. Similarly for loamy sand soil, it ranged from17.11 to 27.28 days at different soil moisture levels. The half life period increased with increased moisture content of soil. The half life values were fairly high for black clay Bellary soil than loamy sand Hessaraghatta soil. The degradation of soil retained fungicide residues followed first order reaction (R2>0.96). The degradation rate constant (K) increased with increasing moisture levels and K was always less in autoclaved condition than of non autoclaved condition. “Kdeg” was fairly high for loamy sand Hessaraghatta soil than that of black clay Bellary soil at particular point of time and treatments. Tue, 01 Jan 2002 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/518 2002-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/517 Title: Persistence and different formulations of imidacloprid in soil and okra (Abelmoschus esculentus L. Moench) plant Authors: H R, Indumathi Abstract: Persistence and degradation of imidacloprid was determined by fortification of soil and incubating under different soil moisture regimes. Plant uptake of imidacloprid was also studied by growing imidacloprid treated okra seeds in glass house. Dissipation pattern of imidacloprid in okra was studied by spraying imidacloprid at effective and a double dose under a supervised field trial at initial fruit set stage (45 days after germination).Imidacloprid dissipated slowly in soil at field capacity as well as 50% field capacity conditions. Residues of imidacloprid persisted for more than 75 days with half lives of 76.8and 74.0 days respectively. There was no marked difference between the persistence of imidacloprid in soil under the two soil moisture conditions studied. The persistence of imidacloprid is only slightly higher at 50% field capacity condition than at field capacity condition. Imidacloprid was taken up by okra plant from treated (9 g a.i./kg) seeds and translocated residues were found to be 1.59 ppm at 15 days after germination. However these residues were detected in the plant for more than 30 days after germination, no residues were detected in fruits at harvest (50 days after germination). Foliar application of imidacloprid in okra resulted in high initial residues (1.12 to 2.01 ppm and 1.34 to 2.21 ppm) in first and second seasons respectively. Imidacloprid residues in okra fruit following spray treatment persisted for more than 10 days in lower concentration (0.3ml/L) and for more than 15 days in higher concentration (0.6ml/L) in both the season. The residue dissipated with a half life of 2.2 to 3.7 days in the first season and 2.4 to 4.0 days in the second season at the recommended and double the recommended doses of application respectively. Sat, 01 Jan 2000 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/517 2000-01-01T00:00:00Z