Browsing by Author "Visveswaran, S"

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Assessment of soil quality in the post flood scenario of AEU 16 in Idukki district of Kerala and generation of GIS maps
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 2020) Sreekutty, M R; Visveswaran, S
Characterisation of soil and irrigation water of the sugarcane belt in Palaghat in relation to yield, nutrient uptake and quality of the cane
(Department of Soil science and Agricultural chemistry, College of Horticulture, Vellanikkara, 1995) Visveswaran, S; Korah, P A
The investigation undertaken, envisages the characterization of the soil and irrigation water of three sugarcane growing regions namely Vannamada, Meenakshipuram and Attapadi in Palghat district and their relation to the nutrient uptake, yield and quality of sugarcane. One hundred and ninety seven surface soil samples (0-15cm) from the three regions were characterized for the major physico- chemical properties. Twenty four farmer’s plots were identified as observation plots to assess the yield, dry matter production and quality parameters of sugarcane juice and the inter relations between these parameters. Samples of irrigation water from four commonly used sources namely bore well, open well, canal, and river water used for irrigating sugarcane plots were collected in the pre monsoon and monsoon periods for determination of quality parameters and to study their effects on the crops. The soils of the three regions were predominantly mildly alkaline in reaction. The EC of these soils were on par with each other and were with in safe limits. The major texture of soils of the area was sandy clay loam, followed immediately by sandy loam. The bulk density, particle density and pore space of the three region did not vary significantly. The water holding capacity and volume expansion of the soils were significantly higher in Vannamada and lowest in Attapadi regions. None of the physical properties had any adverse effect on the growth of sugarcane. Organic matter, total N, P and K recorded low values in soils of the three regions. The rating of available N was medium in all the three regions. For available P and K, the rating for Vannamada and Meenakshipuram regions was medium while for Attapadi it was high. Available S followed the same trend as that of the major nutrient elements and its status in the soils of the three regions was above the critical level. Exchangeable Ca and Mg dominated in all the three regions. Exchangeable Mg and Na were significantly higher in the soils of Vannamada. The levels of micro nutrients viz. Fe, Mn, Zn and Cu in the soils of the three regions were above the sufficiency limits. The quality parameters of irrigation waters such as pH, EC, CI- and SO4- -contents, RSC and SAR studied were within the safe limits for the irrigation of sugarcane. All the three regions recorded high values in yield and dry matter production. However, in comparison Attapadi registered lower values than the other regions. The uptake of N, P, K, Na, Ca and Mg were highest in soils of Meenakshipuram and lowest in Attapadi region. The yield and dry matter production exhibited a significant positive correlation with uptake of N, P, K and Na. The uptake values obtained for micro nutrients were low, which may be attributed to high pH of the soils. Soil of the three regions did not show any significant variation in juice quality parameters such as brix, pol value, purity and commercial cane sugar content. Juice quality parameters were significantly and positively correlated with N, P, K and Na.
Dissipation and distribution of fipronil, carbosulfan and their metabolites in banana var. Nendran (AAB) and soil
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2021) Visveswaran, S; Thomas George
The study entitled “Dissipation and distribution of fipronil and carbosulfan and their metabolites in banana (Musa spp) and soil” was carried out at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani during the period from August 2016 to April 2017. The objective was to assess the dissipation, metabolism and persistence of fipronil and carbosulfan in banana, cv. Nendran (AAB), grown under red loam soils (AEU 8-southern laterites) of College of Agriculture, Vellayani, and its impact on soil organisms. Banana variety Nendran, grown as per package of practices recommendations, KAU in randomized block design at the Instructional Farm, Vellayani, with five treatments viz., T1- absolute control (No application of carbosulfan and or fipronil), T2- recommended practice of 30 mg ai of fipronil per plant per application, applied 3 times on 0, 60 and 150 days of planting, T3 – double dose of T2, T4- recommended practice of 400 mg ai of carbosulfan per plant per application, applied 3 times on 0, 60 and 150 days of planting and T5- double the dose of T4. Samples viz, soil, leaves, fingers bunches and flower bud, central core of pseudo-stem and corm were collected and analyzed for residue at definite time intervals. The residue estimation of the target pesticide molecules and their toxic metabolites were performed by adopting standard extraction and clean up procedure viz., conventional acetone extraction followed by hexane partitioning as well as by QuEChERS method. Method validation was conducted by spiking with analytical standards from which recovery, (accuracy 70-120% of spiked values), standard deviation of recoveries, RSD value (below 20%), linearity (calibration curve), for the adopted method were worked out and compared for compliance. Acetonitrile extracted samples were analyzed using “Waters Acuity UPLC 137 system” with suitable column and then subjecting the effluent to triple quadrupole API 3200 MS/MS system equipped with electrospray ionization interface (ESI) operating in required mode as per the molecule. Extraction using QuEChERS method gave satisfactory values for validation parameters and hence adopted for the studies. The presence of carbosulfan in the 1st to 4th leaves till day 20th and subsequent dissipation pattern prediction for BDL in 22.5 day indicated that, at recommended dose of application, it is not safe to use the leaves within 23 days of application for serving or food packing (as commonly practiced in many households of Kerala). Sample matrices revealed the presence of metabolites each for fipronil and carbosulfan with variation from below detectable limit (BDL) to a highest content of 3.804 μg/g carbosulfan at 2 hours of application in the soil. Blossom bud, flower bract alone, bunch on 15th day of emergence, bunch on 30th day of emergence, peel, bunch on harvest, pseudo stem and corm did not register any detectable level of fipronil or carbosulfan and their metabolites and even with an additional application of treatment on the day of bunching also did not register any detectable level of fipronil or carbosulfan and their metabolites. Residue of fipronil and their toxic metabolites in the first, second and third leaves of banana on penultimate day of completion of pre-bunching application was found to be below the detectable levels throughout the period of sampling and this may be attributed to low absorption, fast metabolism and mobility. However, on 40th day the fipronil was detected in the 4th leaf to the extent of 0.034 μg g-1 and was not detectable on 50th day. Metabolites of Carbosulfan residue existed in the first, second and third leaves between 5th and 20th day and it dissipated to below detectable limit on 40th day of application. The content of residue under treatment T5 was distinctly higher than T4 during these periods and dissipated to BDL on 25th day. 138 In soil, the fipronil though dissipated to BDL before 50th day, persisted from 2 hours of application till 40th day. However, carbosulfan and its metabolites were early to dissipate to BDL on 7th day of completion of application. Sample in experiment with 5 times the recommended dose of application as injection into pseudostem at the time of bunch emergence also did not record any residue above detectable level in the flower bud, flower bract alone, bunch on 15th day of emergence, bunch on 30th day of emergence, peel, bunch on harvest and pseudostem. Soil urease activity on 10th day was significantly influenced by the treatment where T1, T3 and T5 are significantly lower than T2 and T4. However, dehydrogenase activity and acid phosphatase activity were not significantly influenced by the treatment. Bacterial population was higher in T1. Treatments were found to significantly influence the weight of blossom bud on dehorning, pseudostem, bunches and corm. Other biometric parameters were not influenced by the treatment. The above results show complete dissipation of fipronil and carbosulfan to safe limits in soil and banana leaf, when applied as per package of practices recommendation for banana cultivation (fipronil 30 mg a.i. and carbosulfan 400 mg a.i. per plant applied thrice viz., on 0, 60 and 150 days of planting), within 50 and 23 days of application. Also, the application of fipronil and carbosulfan as per the above dose in no way results in the accumulation of residue on any of the edible plant parts of banana and hence it is safe for human consumption.
Evaluation of STCR based targeted yield equations of amaranthus (Amaranthus tricolor L.) in southern laterite soils of (AEU-8) of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture,Vellayani, 2023-05-06) Dara Hadassah Eunice; Visveswaran, S