PG Thesis
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Item Sorption and movement of cyantraniliprole in sandy loam soils with and without organic amendments(Department of Soil Science and Agricultural Chemistry , Vellayani, 2021-10-08) Al Noufiya, S; Thomas GeorgeThe study entitled “Sorption and movement of cyantraniliprole in sandy loam soils with and without organic amendments” was conducted in the Department of Soil Science and Agricultural Chemistry and the laboratory attached to the All India Network Project (AINP) on Pesticide Residues, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala during 2019-21. The main objectives of the experiment were to study the adsorption, desorption, persistence and leaching of cyantraniliprole in sandy loam soils with and without addition of organic amendment at the rate of 0.5 per cent Farm Yard Manure (FYM). The soil was collected from the sandy belts of Kazhakkoottam, Thiruvananthapuram. The physical and chemical analysis of the soil revealed that the soil was moderately acidic, with 0.84 per cent organic matter, 11.80 per cent clay, 22.30 per cent silt and 65.90 per cent sand. Among the major nutrients, phosphorus content was found to be high; potassium was medium while the other nutrients were low. The method for estimation of cyantraniliprole residues in soil were validated by modified QuEChERS method and was found ideal. Liquid- liquid partitioning using dichloromethane was found suitable for cyantraniliprole residue estimation in water. The adsorption-desorption studies were carried out at 5 different concentrations of 20, 40, 60, 80 and 100 μg levels each both in normal soil and 0.5 per cent FYM amended soil in Completely Randomized Design (CRD) with ten treatments and three replications and was repeated by direct spiking also. The adsorption- desorption data fitted well in Freundlich adsorption isotherm. The distribution coefficient, K d (mean value) was found high in amended soil (2.55) than normal soil (2.40) which indicated increased sorption in relation to organic matter content. The K f values (adsorption coefficient) were 2.60 and 2.45 for amended and normal soil respectively, indicating a high sorption capacity for the amended soil. The desorption was carried out in three cycles, the percentage desorption was decreasing in each consecutive cycle. In all levels of concentration, desorption was slower than adsorption indicating a hysteresis effect. In the soil samples directly spikedwith cyantraniliprole also, the desorption percentages were found lower and formed a still higher hysteresis. Mobility of cyantraniliprole was assessed in CRD with eighteen treatments and three replications i.e., by loading 3 levels viz., 25, 50 and 75 μg concentrations of cyantraniliprole, separately on top of 200 g soil columns loaded in PVC pipes and followed by eluting with 40, 80 and 160 mL of water @ 0.4 ml min -1 . In all the treatments residues were obtained in 0-25 cm packed columns and also in the leachate. In the normal soil, cyantraniliprole moved down the soil column which resulted in residue levels ranging from 7.48-3.98, 19.27- 9.57 and 27.67- 13.41 μg at 25, 50 and 75 μg levels, respectively when eluted with different volumes of water. In the soil amended with 0.5 per cent FYM, the corresponding residues ranged from 10.41- 4.48, 21.08- 9.89 and 29.98- 14.19 μg at 25, 50 and 75 μg levels indicating a higher retention in soil. The persistence of cyantraniliprole in normal soil and amended soil under three soil moisture conditions (air dry, field capacity and saturated) were studied using the formulation of cyantraniliprole added at the rate of 1, 2 and 4 mg kg -1 in CRD with eighteen treatments and three replications. The half- life of cyantraniliprole was found highest in amended soil spiked with 4 mg kg -1 cyantraniliprole under air dry soil condition i.e., 32.44 days followed by the same under normal soil condition i.e., 30.45 days. In the persistence study, no metabolites of cyantraniliprole were detected. The study concluded that the adsorption coefficient was higher in FYM amended soil indicating stronger adsorption than normal soil and the desorption percentages were reduced in the same. Hysteresis effect was noticed in all the treatments indicating slower desorption than adsorption. The mobility of cyantraniliprole was found to be slightly higher in normal soil compared to the 0.5 per cent FYM amended soil and also indicates its moderate mobility behaviour. The dissipation was found to be the fastest under submerged condition followed by field capacity and air dry conditions.Item Fortifid organic matrix pellets for crop nutritional resilience in Onattukara sandy loam soils(cultural Chemistry, Department of Soil Science and Agri College of Agriculture , Vellayani, 2023-05-15) Neema, V H.; Mini ,VA study on “Fortified organic matrix pellets for crop nutritional resilience in Onattukara sandy loam soils” was carried out during 2020-2022 in the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani. Objective of the study was to fortify the organic matrix developed from agro wastes with macro and micro nutrients and to evaluate the effect of this fortified organic matrix pellets on yield and quality of chilli in the sandy loam soils of Onattukara. The study comprised of three parts viz., development of fortified organic matrix, nutrient leachate experiment and evaluation of the effect of fortified organic matrix pellets on growth and yield of chilli. Biodegradable agro waste materials viz., rice husk, rice husk ash, cow dung, coir pith compost, vermicompost, poultry manure, neem cake and ground nut cake were combined in 1: 4: 5: 1: 2: 1: 1: 1 ratio to develop the organic matrix. The developed organic matrix was fortified with essential nutrients viz., N (1.2%), P (0.4 %), K (0.82%), Ca (0.12%), Mg (0.13), S (0.10%), Fe (0.04%), Mn (0.02%), Zn (0.06%), Cu (0.02%), B (0.10%) and Mo (0.01%), considering the nutrient requirement of chilli and general soil status of Onattukara. Carriers of various macro and micro nutrients viz., urea, rajphos, muriate of potash, calcium nitrate, magnesium sulphate, ferrous sulphate, manganese sulphate, zinc sulphate, copper sulphate, borax and ammonium molybdate were used for fortifying the organic matrix. Fortified matrix was converted into pellet forms for soil application. Onattukara soils are generally coarse textured with low organic matter content. Nutrient supplying capacity of this sandy plain is declining due to nutrient loss through surface runoff and leaching. Nutrient leachate experiment was conducted to assess the leaching loss of nutrients and the leachates were collected to analyse macro and micro nutrients. Four saturation times were evaluated viz., 10 min, 1 day, 5 days, and 10 days. The 10-min saturation was designed to mimic precipitation that runs through the soil immediately following a short duration rain event. The 1-day saturation was designed to mimic a longer rain event, which might cause localized ponding due to saturated subsoil. The 5-day and 10-day saturation events were designed to mimic the leaching during flood events. Four treatments viz. T1- organic matrix mixed with soil, T2-fertilizer mixed with soil, T3-fortified organic matrix mixed with soil and T4-control (soil alone) were taken (20 parts water to 1part solid ratio) for nutrient leachate study. An increase in nutrient content in the leachate was observed during the study and the average increase in nutrient content was less in T1 and T3 compared to T2 and T4. This indicated the effect of organic matrix in reducing the leaching loss of nutrients. 122 A field experiment was conducted to evaluate the effect of various doses and time of application of fortified organic matrix pellets on growth and yield of chilli in the Onattukara sandy plains during January,2022 to April, 2022.The experiment consisted of eight treatments and they were T1 (Recommended dose of fertilizers and organic manure (as FYM) as per POP), T2 (Recommended dose of fertilizers and organic manure (as organic matrix) as per POP) ,T3 (Fortified organic matrix pellets @ 500g/plant in three splits) ,T4 (Fortified organic matrix pellets @ 500g/plant in two splits) T5 (Fortified organic matrix pellets @ 400g/plant in three splits), T6 (Fortified organic matrix pellets @ 400g/plant in two splits), T7 (Fortified organic matrix pellets @ 300g/plant in three splits) and T8 (Fortified organic matrix pellets @ 300 g / plant in two splits).Growth, yield and quality of chilli increased significantly due to the application of fortified organic matrix pellets. The highest plant height (67.0 cm) was recorded in the treatment T4 and it was on par with T3. Treatment T4 recorded the highest fruit set percentage (77.60 %) which was on par with treatments T3 and T6. The highest root length (42.6 cm), root volume (48.3 cm3) and root dry weight (19.0 g) was also recorded in T4. The treatment T4 (Fortified organic matrix pellets @ 500g/plant in two splits) recorded significantly higher values for number of fruits per plant and fruit weight and recorded the highest yield (0.63 kg per plant). The highest values for the quality parameters such as ascorbic acid (42.0 mg 100 g -1) and capsaicin (0.77%) were also recorded in T4. Soil analysis after the experiment showed that there was as improvement in water holding capacity of the soil and treatment T4 recorded the highest value (29.42 %) and it was on par with T2, T6 and T7. The treatment did not show any significant influence on pH of soil and the electrical conductivity was also in the non-saline range. The highest organic carbon (0.71 %) was recorded for T4 and it was on par with T1 and T2. In the case of available N, treatment T4 recorded the highest values (225.80 kg ha -1) and it was on par with T3 and for available P, the highest value (52.53 kg ha -1) was recorded for T4 which is significantly superior to all other treatments. Treatment T4 recorded the highest value for available K, (148.26 kg ha -1) and it was on par with T1, T2, T3, T6, and T8. The highest content of secondary and micronutrients were also recorded in T4. The treatment T4 (fortified organic matrix pellets @ 500g/plant in two splits) improved the status of microbial biomass carbon (140.53 mg kg -1) and dehydrogenase activity (29.98 µg TPF g -1 24h- 1 soil) and it was on par with T1, T2 and T3. Labile carbon pools were also high in T4 and it was on par with T1 and T2. The results of the shoot analysis revealed that the treatment T4 recorded significantly higher content of N (3.73 %). The highest P content (0.38%) in the shoot was recorded in T4 123 and it was on par with T1, T2, T3, T5 and T6. The highest potassium content (2.74 %) was recorded in T4 and it was on par with T3. Status of secondary nutrients also improved in all the treatments and recorded the highest values for treatment T4. In case of micronutrients, highest value of B (11.22 mg kg -1), Cu (5.15 mg kg -1) and Zn (26.24 mg kg -1) were recorded for T4 and was significantly superior to all other treatments. The results of the fruit analysis revealed that the treatment T4 recorded the highest N (2.39 %), P (0.25 %) and K (1.81 %) content and similar observation was recorded for secondary and micronutrients. There was no major pest and disease incidence in the crop. Treatment T4 recorded the highest net return (Rs.8,54,185/ ) and B:C ratio (2.22). Present study revealed that, treatment T4 (Fortified organic matrix pellets @ 500g/plant in two splits) is the best treatment for improving the yield and soil nutrient status. Application of fortified organic matrix made from agricultural wastes and macro- and micronutrients decreased the leaching loss of nutrients, increased the yield and quality of chilli and enhanced soil health in Onattukara sandy loam soils. Use of fortified organic matrix fertilizer pellets improved the physical, chemical and biological properties of the soil. From the investigation, it can be concluded that the application of enriched organic matrix pellets @ 500g/plant in two splits at basal and 45 days after transplanting was the best treatment for increasing production, soil nutrient status and to ensure crop nutritional resilience in Onattukara sandy loam soils. 12