Browsing by Author "Usha, C Thomas"

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    Production technology of grain sorghum (Sorghum bicolor L. Moench) in summer rice fallows
    (Department of Agronomy, College of Agriculture, Vellayani, 2024-12-13) Anuranj, R; Usha, C Thomas
    The study entitled “Production technology of grain sorghum (Sorghum bicolor L. Moench) in summer rice fallows” was undertaken at College of Agriculture, Vellayani, during 2022-2024. The objective was to standardize the tillage, plant population and nutrient management for grain sorghum in summer rice fallows. The field experiment was carried out at Instructional Farm, Vellayani, from January to May 2024. The experiment was laid out in design RCBD with 2 x 2 x 3 treatments, replicated thrice. The treatments comprised combinations of two tillage methods (t1-zero tillage, t2-conventional tillage), two levels of spacing (p1 – 45 x 15 cm, p2- 60 x 15 cm) and three levels of NPK (n1 – 45:25:25 NPK kg ha-1, n2 – 50:25:75 NPK kg ha-1 and n3 – 50:25:50 NPK kg ha-1). The variety used for the study was CO-32. Sorghum grown under conventional tillage (t2) resulted in taller plants, higher Leaf area index (LAI) at 30 DAS and higher number of leaves at 60 DAS and at harvest. Sorghum grown with a spacing of 60 x 15 cm (p2) recorded higher number of leaves at all stages of growth. Sorghum grown with a spacing of 45 x 15 cm (p1) recorded higher LAI at all stages of growth. With respect to nutrient management n2 (50:25:75 NPK kg ha-1) recorded taller plants at 90 DAS and at harvest, higher number of leaves at 90 DAS and higher LAI at 30 and 90 DAS. Sorghum grown under conventional tillage with spacing 45 x 15 cm and a nutrient dose of 50:25:75 NPK kg ha-1 (t2p1n2) resulted in taller plants at harvest (288.03 cm) which was at par with t2p1n3. Sorghum grown under conventional tillage with spacing 45 x 15 cm and a nutrient dose of 50:25:75 NPK kg ha-1 (t2p1n3) recorded higher LAI at 30 DAS (3.13) which was at par with t2p1n2. Sorghum grown under conventional tillage (t2) recorded higher Crop growth rate (CGR) and Relative growth rate (RGR) at 30-60 DAS interval and higher dry matter production (DMP) at 30 and 60 DAS whereas sorghum grown under zero tillage (t1) recorded higher CGR and RGR at 60-90 DAS interval and DMP at 90 DAS and at harvest. Higher CGR, RGR and DMP were estimated in sorghum grown with a spacing of 45 x 15 cm (p1) at all stages of growth. With respect to nutrient management treatments, n2 (50:25:75 NPK kg ha-1) resulted in higher CGR, RGR and DMP and was statistically comparable with n3 (50:25:50 NPK kg ha-1). The lowest number of days for 50 percent flowering (64.08 days) was recorded in the treatment n2 (50:25:75 NPK kg ha-1). Among yield attributes, sorghum grown under zero tillage with spacing 45 x 15 cm and a nutrient dose of 50:25:50 NPK kg ha-1 (t1p1n3) resulted in higher length of panicle (22.70 cm), number of grains per panicle (1836.67) and grain weight per panicle (35.96 g). Higher grain yield (5.14 t ha-1) was obtained in treatment t1p1n3, which was found on par with t1p1n2 (4.96 t ha-1) and higher stover yield (8.10 t ha-1) was obtained in treatment t1p1n2 which was found on par with t1p1n3 (7.81 t ha-1). Harvest index was higher in the treatment t2p2n1 (0.43) and remained comparable with t1p1n3 (0.40) and t1p1n2 (0.39). Sorghum grown under zero tillage recorded higher chlorophyll content (3.50 mg g -1 and 3.86 mg g -1) at 30 DAS and 60 DAS respectively and in case of nutrient application treatment n3 (50:25:50 NPK kg ha-1) recorded higher chlorophyll content and was at par with n2 (50:25:75 NPK kg ha-1) at 30 DAS and n2 (50:25:75 NPK kg ha 1) recorded higher chlorophyll content at 60 DAS. The N uptake of sorghum was higher (258.36 kg ha-1) when grown under zero tillage with spacing 45 x 15 cm and a nutrient dose of 50:25:75 NPK kg ha-1 (t1p1n2) and was found on par with t1p1n3 (242.47 kg ha-1). The uptake of P was found higher (67.38 kg ha-1) in treatment t1p1n3. The uptake of K was higher (379.57 kg ha-1) in treatment t1p1n3 which was on par with t1p1n2 (339.64 kg ha-1). Post-experiment soil analysis revealed that sorghum grown under conventional tillage resulted in higher pH (6.93) and electrical conductivity (0.54 dS m-1). With respect to nutrient management treatment n3 (50:25:50 NPK kg ha-1) recorded higher pH and electrical conductivity. Sorghum under zero tillage (t1) recorded the highest organic carbon content (1.44 %) and in case of nutrient management treatment n2 (50:25:75 NPK kg ha-1) recorded higher organic carbon content which was on par with n3 (50:25:50 NPK kg ha-1). The available N (205.86 kg ha-1), available P (88.24 kg ha 1 ) and available K (93.33 kg ha-1) status of soil was higher under zero tillage (t1). Sorghum grown with a spacing 60 x 15 cm recorded higher available N, available P and available K. In case of nutrient management treatments n3 (50:25:50 NPK kg ha-1) recorded higher available N and n1 (45:25:25 NPK kg ha-1) resulted in higher available P. The treatment n2 (50:25:75 NPK kg ha-1) recorded higher available K which was found on par with n3 (50:25:50 NPK kg ha-1). The economic analysis revealed that, among the treatment combinations t1p1n3 resulted in higher net income (98676 ₹ ha-1) and benefit cost ratio (2.77). Considering yield and economics of cultivation, sorghum may be recommended for cultivation in summer rice fallows with zero tillage, spacing of 45 cm x 15 cm and application of 50:25:50 kg NPK ha-1 along with 5 t ha-1 of FYM.
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    Standardization of spacing and nitrogen management of multicut fodder sorghum(Sorghum bicolor x Sorghum sudanense)
    (Department of Agronomy,College of Agriculture , Vellayani, 2024-07-05) Bukke Sathish Kumar Naik; Usha, C Thomas
    The study entitled “Standardization of spacing and nitrogen management of multicut fodder sorghum (Sorghum bicolor x Sorghum sudanense)” was undertaken at Instructional Farm, College of Agriculture, Vellayani, during 2021 to 2023. The key objective was to assess the influence of row to row spacing and nitrogen application on growth, yield, and quality aspects of multicut fodder sorghum. The field experiment was carried out at Instructional Farm, College of Agriculture, Vellayani, from November 2022 to August 2023. It was laid out in randomized block design with (3 x 3) + 1 treatments, replicated thrice. The treatment combinations included three levels each of row spacing (R) (r1- 20 cm, r2- 30 cm, r3- 40 cm) and nitrogen application (N) in seven equal splits (n1- 315 kg ha-1, n2- 245 kg ha-1, n3- 175 kg ha-1), compared against the control treatment (30 cm row spacing, nitrogen application- 315 kg ha-1 in seven equal splits, and MgSO4- 80 kg ha-1). Nitrogen was applied in seven splits- as basal, 20, and 40 days after sowing and after each cut. The variety used for the study was COFS-31, released from Tamil Nadu Agricultural University. A total of five cuts were taken during the study period. The treatment, r2 (30 cm row spacing) resulted in significantly taller plants with more leaves at harvest, the longest and broadest leaves, the highest leaf stem ratio, LAI at harvest, LAD, CGR, and RGR (at 30-60 DAS). The treatment, r3 (40 cm row spacing) resulted in the highest stem girth, and SLA (at harvest). Among the levels of nitrogen application, 315 kg N ha-1 (n1) recorded significantly taller plants with more leaves at harvest, the highest leaf length, leaf breadth, leaf stem ratio, stem girth, LAI, and SLA (at harvest), LAD, CGR, and RGR (at 30-60 DAS). Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in taller plants (235.78 cm), with the highest CGR (30-60 DAS). It resulted in a higher leaf stem ratio (0.55) and was on par with r3n1 (0.53). The treatment combination, r1n1 resulted in the highest LAI (6.19) at harvest. The treatment combination, r3n1 resulted in the highest SLA at harvest. The control treatment was superior over all the treatment combinations concerning growth attributes. The treatments, r2 (30 cm row spacing), and n1 (315 kg N ha-1) resulted in the highest total green fodder yield (148.09 t ha-1 and 159.87 t ha-1 respectively) and dry fodder yield (34.56 t ha-1 and 37.36 t ha-1 respectively). Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in the highest total green fodder yield (172.58 t ha-1) and dry fodder yield (40.60 t ha-1). The control treatment was superior over all the treatment combinations concerning green fodder yield (175.8 t ha-1) and dry fodder yield (41.52 t ha-1). The treatment, r2 (30 cm row spacing) significantly produced the highest chlorophyll content (1.94 mg g-1) at harvest. Among the levels of nitrogen application, 315 kg N ha-1 (n1) recorded significantly the highest chlorophyll content (1.95 mg g-1), and crude protein percent (9.03 %) at harvest. The control treatment did not show any significant influence on chlorophyll content and crude protein content over all the treatment combinations. The treatments, r2 (30 cm row spacing), and n1 (315 kg N ha-1) resulted in the highest NPK uptake. Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in the highest NPK uptake. The control treatment was superior to all the treatment combinations concerning NPK uptake. The treatment, r3 (40 cm row spacing) resulted in significantly the highest soil available P and K, higher soil available N, and Mg which were on par with the treatment r1 (20 cm row spacing). The treatment, n3 (175 kg N ha-1) resulted in the highest soil available P, K, and Mg, with higher soil available N, and was on par with the treatment n2 (245 kg N ha-1). Among the treatment combinations, r3n3 (40 cm row spacing + 175 kg N ha-1) resulted in the highest soil available P, K, and higher soil available N which was on par with the treatment combinations r1n1, r1n2, r3n2. Among the treatment combinations, r3n3 (40 cm row spacing + 175 kg N ha-1) resulted in higher soil available Mg which was on par with the treatment combinations r1n3, and r3n2. The treatments, r2 (30 cm row spacing), and n1 (315 kg N ha-1) resulted in the highest benefit cost ratio (2.09 and 2.23 respectively). Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in a higher benefit cost ratio (2.52) which was comparable with r3n1 (2.32). The control treatment was superior over all the treatment combinations in terms of benefit cost ratio (2.77). Based on the study, it could be inferred that multicut fodder sorghum is suitable for cultivation in Kerala when grown at a row spacing (30 cm) and nitrogen dose of 315 kg ha-1 y-1 (seven equal splits) along with FYM- 10 t ha-1, P2O5- 40 kg ha-1 y-1, K2O- 40 kg ha-1 y-1, and MgSO4- 80 kg ha-1 y-1.
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    Yield performance and stress responses of sorghum
    (Department of Agronomy, College of Agriculture, Vellayani, 2025-10-23) Swathy, A H; Usha, C Thomas
    Climate change has emerged as one of the most important global environment issues. Rising CO2 and temperature, changing rainfall patterns, and an increase in the frequency and duration of heat stress and water stress are all effects of climate change. Sorghum being a C4 plant with increased photosynthetic efficiency and abiotic stress tolerance, is a key crop in semi-arid tropical regions. Assessing the impact of climate change on sorghum productivity is crucial for addressing future food security challenges. This PhD project aimed to assess yield performance, response to water and heat stress in sorghum. In the first part of the project (chapter 2), twenty grain sorghum varieties were evaluated for the yield performance and variations in plant and leaf morphology. In the second part (Chapter 3), four sorghum genotypes including two grain sorghum (Sorghum bicolor ‘Farfara’ and Sorghum sudenense) and two wild sorghum (Sorghum bulbosum and Sorghum macrospermum) genotypes were grown focusing on studying the responses of these genotypes under water stress and heat stress conditions. In the third part (chapter 4), a large population of sorghum genotypes with different aquaporin alleles were grown to study the link between stomatal anatomy and kinetics and their relationship with water use efficiency under water stress. The first experiment was carried out in field conditions at College of Agriculture, Vellayani, Kerala, India. The second and third experiments were carried out in potted plants grown in the glasshouse at Hawkesbury Institute for the Environment, Western Sydney University, Australia. The first experiment revealed significant variations in growth and yield attributes among different sorghum varieties at various stages of development. CSV 17 performed exceptionally well across a variety of measures. It showed significantly higher grain yield, early flowering, and a shorter time to maturity, and higher harvest index compared to other varieties. CSV 20 demonstrated impressive economic performance, with the highest net returns per hectare and a remarkable benefit-cost ratio due to its significantly higher stover yield. In terms of leaf area index (LAI) and leaf area duration (LAD) variety CSV36 performed better. In second experiment S. bicolor ‘Farfara’ exceled in maintaining high intrinsic water use efficiency (iWUE) and quantum yield of photosystem II (ΦPSII) under water stress, while S. bulbosum excelled by maintaining carbon assimilation rate (An) and stomatal conductance (gs). In third experiment we observed a large variation in stomatal kinetics and their related dynamic water use efficiency and only stomatal opening speed (kopen) was found to be affected by water stress among other stomatal traits. The results of this research will provide valuable data for breeding programs focused on creating new sorghum varieties