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    Weed management in semi-dry rice of semi-dry rice Onattukara sandy plains
    (Department of Agronomy, College of Agriculture, Vellayani, 2024-03-14) Rachana, V R; Jacob, D
    The study entitled “Weed management in semi-dry rice of Onattukara Sandy Plains” was conducted at College of Agriculture, Vellayani during 2021-2023. The objective of the study was evaluation of ready-mix pre-emergence and post-emergence herbicides for weed management and their effect on growth and yield of semi-dry rice in Onattukara region. The field experiment was carried out in farmer’s field at Onattukara Sandy Plains (AEU 3) during kharif season 2023. The experiment was laid out in RBD with eight treatments and three replications. The treatments comprised pre-emergence (PE) pendimethalin + pyrazosulfuron ethyl 787 g ha-1 followed by (fb) post-emergence (PoE) triafamone + ethoxysulfuron 60 g ha-1 (T1), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb PoE penoxsulam + cyhalofop butyl 135 g ha-1 (T2), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb PoE bispyribac sodium 25 g ha-1 (T3), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb mechanical weeding at 25 DAS (T4), PE pendimethalin 770 g ha-1 fb mechanical weeding at 25 DAS (T5), mechanical weeding twice at 15 and 30 DAS (T6), hand weeding twice at 15 and 30 DAS (T7), and weedy check (T8). Ready-mix formulations of pendimethalin + pyrazosulfuron ethyl, triafamone + ethoxysulfuron and penoxsulam + cyhalofop butyl were used in the study. Pre-emergence herbicides were applied on the next day after sowing and post emergence herbicides were applied at 25 DAS. Mechanical weeding was done with wheel hoe weeder. The short duration rice variety ‘Bhagya’ was used in the study. Weed management practices significantly influenced the growth parametres such as plant height, number of tillers per square metre, and dry matter per hill. In comparison to other weed management treatments, treatments (T1, T2, T3, and T4) that recieved PE pendimethalin + pyrazosulfuron ethyl had taller plants and more tillers per square metre at 20 DAS. PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) recorded significantly higher plant height (64, 92, and 106 cm), more number of tillers per square metre (486, 552, and 515) and dry matter production per hill (8.08, 14.47, and 17.70 g) at 40 DAS, 60 DAS and harvest. 98 Leaf area index (LAI) was higher in T1, T2, T3, and T4 at 20 DAS. Treatment T2 resulted in higher LAI at 40 DAS (3.27) and 60 DAS (6.23). Crop growth rate (CGR) observed in T2 during 20-40 DAS (18.20 g m-2 d-1) was higher and showed an increase during 40-60 DAS (21.29 g m-2 d-1). Relative growth rate (RGR) was higher in T2 during 20-40 DAS (0.057 g g-1 d-1) than T1, T3, T4, T5, and T6. During 40-60 DAS, RGR in T2 was comparable. Weed management practices significantly influenced the yield attributes of rice. Treatment T2 resulted in higher number of productive tillers per square metre (462), greater number of spikelets (120) and filled grains per panicle (108), heavier grains per panicle (3.09 g), and the lowest sterility percentage (10.40 %). The combination of PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) resulted in significant increase in grain yield (4960 kg ha-1), straw yield (6175 kg ha-1), and harvest index (0.45). Compared to treatment T7 (hand weeded twice at 15 DAS and 30 DAS) treatment T2 exhibited about a 40 per cent increase in grain yield. Treatment T2 had the lowest weed index (0.00 %), followed by T1 (7.63 %). Highest weed index in weedy check indicated that presence of weed resulted in 56.32 % yield reduction. Treatment T2 had the lowest weed index (0.00 %), followed by T1 (7.63 %). Highest weed index in weedy check indicated that presence of weed resulted in 56.32 % yield reduction. The major weed species observed in the experimental field were categorised in to grasses, sedges and broad leaf weeds. Oryza sativa f. spontanea, Isachne miliacea Roth ex Roem et Schult, Eleusine indica (L.) Gaertn, Echinochloa colona L., Sacciolepis interrupta (Wild). Stapf, and Paspalum distichum L. were the major grasses. Cyperus iria L., Cyperus difformis L., and Fimbristylis miliacea (L.) Vahl were the major sedges. Ludwigia perennis L., Melochia corchorifolia L., Marsilea quadrifolia L. and Monochoria vaginalis (Burm. f.) C. Presl ex Kunth were the major broad leaf weeds observed in the experimental field. Weed management practices significantly reduced the absolute density of weeds. The treatments T1, T2, T3, and T4 exhibited lower absolute densities of grasses, sedges, and broad leaf weeds at 20 DAS. Whereas, T2 resulted in lower absolute density at 40 99 DAS and 60 DAS. At 40 DAS, the relative densities of grasses (34.95%), sedges (33.73%), and broad-leaf weeds (31.21%) in T2 indicating a larger proportion of grasses in total weed population. Compared to other treatments, T2 significantly lowered weed dry weight at 40 DAS (14.68 g m-2) and 60 DAS (26.14 g m-2) which resulted in higher weed control efficiency of 82.83 %, and 80.77 % at 40 DAS and 60 DAS. The treatment T2 resulted in higher nitrogen (140 kg ha-1) uptake by crop at harvest and it was on par with T1. The phosphorus uptake was highest in T2 (34 kg ha 1). The higher potassium (118 kg ha-1) uptake was recorded in treatment T2 and was comparable with T1, T3 and T4. The treatment T2 recorded lower weed removal of N, P, and K at 40 DAS and 60 DAS. The post-experimental soil available NPK were also observed to be higher in T2. The soil enzyme activity was significantly influenced by weed management treatments. Among the treatments, T2 recorded higher dehydrogenase activity at 40 DAS and 60 DAS. Urease activity at 40 DAS and 60 DAS were higher in T2 and was comparable with T1 and T3. Considering the treatments, PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) resulted in highest gross income (₹ 204488 ha-1), net income (₹ 58943 ha-1) and Benefit: Cost ratio (1.41). It could be concluded from the study that, the pre-emergence application of ready-mix pendimethalin + pyrazosulfuron ethyl 787 g ha-1 at 0-3 DAS followed by post emergence application of ready-mix penoxsulam + cyhalofop butyl 135 g ha-1 at 25 DAS can be recommended as a cost-effective weed management practice for better weed control, higher yield and net income in semi-dry rice at Onattukara Sandy Plains.
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    Polymer based nano pendimethalin for weed management in rice (Oryza sativa L.)
    (Department of Agronomy, College of Agriculture, Vellayani, 2025-01-27) Rinsiya, V.
    The study entitled “Propagation studies in teasel gourd [Momordica subangulata Blume subsp. renigera (G.Don) de Wilde]” was conducted at the Department of Vegetable Science, College of Agriculture, Vellayani during 2023- 2024 to standardize the rooting media and propagation techniques in teasel gourd and to assess the growth and yield under field conditions. The study was conducted as three experiments. The first experiment on “Standardization of propagation using cuttings’’ was undertaken from October to December 2023. The treatments were factorial combinations of three types of cutting (top, middle and basal), four concentrations of IBA (0, 250 ppm, 500 ppm and 750 ppm) and three types of rooting media such as cocopeat, cocopeat + vermicompost (1:1) and cocopeat + vermiculite + perlite (3:1:1) arranged in completely randomized design with three replications. The basal cuttings recorded earliest sprouting (13.76 days), highest percentages of sprouting and survival (61.03 % and 60.08 %), longest shoot length, root length and highest number of roots per cutting. Among IBA concentrations, the earliest sprouting was observed in control (11.48 days), while 250 ppm recorded the highest sprouting percentage (70.07 %), survival percentage (69.07 %), shoot length, number of leaves and primary branches per cutting. The highest number of roots (41.81) and root length (7.34 cm) were observed in IBA 750 ppm. Cocopeat + vermicompost (1:1) media was found to be significantly superior to other media in sprouting, survival and growth parameters. Among the treatment combinations, basal cuttings treated with 250 ppm IBA and planted in cocopeat + vermicompost (1:1) recorded the highest sprouting percentage (85.00 %), survival percentage (83.67 %) and shoot length (48.90 cm) at 45 DAP. Whereas, the highest number of roots was observed in basal cuttings treated with 750 ppm IBA and planted in cocopeat + vermicompost (1:1) 124 (50.67). The second experiment on “Standardization of propagation using tubers’’ was laid out in completely randomized design with six treatments such as two types of tuber (whole tuber, cut tuber) and three types of potting media (soil + cocopeat + FYM (1:1:1), cocopeat + vermicompost (1:1) and sand) replicated four times. Cut tubers exhibited earliest sprouting, (15.36 days) maximum sprouting and survival percentages (75.83 % and 74.83 %), highest shoot length (140.50 cm), number of leaves and root length per tuber. Whereas, the highest number of shoots (2.97) and roots (42.22) were recorded in whole tubers. Among the potting media, soil +cocopeat + FYM (1:1:1) showed the best results in sprouting, survival and in other growth parameters, which was on par with cocopeat + vermicompost (1:1) medium. Among the treatment combinations, cut tubers planted in soil + cocopeat + FYM recorded the highest survival percentage (86.50 %), shoot length (158.49 cm), number of leaves (27.83) and root length (31.61 cm) at 45 DAP. The three best treatments from experiments I and II were selected along with seedlings for the third experiment ‘Evaluation of propagule in the field’. The field experiment was laid out in RBD with seven treatments in three replications. The treatments were, T1 - basal cuttings treated with 250 ppm IBA and planted in cocopeat + vermicompost, T2 - middle cuttings treated with 250 ppm IBA and planted in cocopeat + vermicompost, T3 - basal cuttings without IBA treatment and planted in cocopeat + vermicompost, T4 - cut tuber planted in soil + cocopeat + FYM, T5 – cut tuber planted in cocopeat + vermicompost, T6 - whole tuber planted in soil + cocopeat + FYM and T7- seedlings. The longest vine (10.13 m), number of days taken for first flowering (32.78 days), number of days to first harvest (40.89 days) and longest crop 125 duration (236.22 days) were recorded in T4 (cut tuber planted in soil + cocopeat + FYM). The highest number of fruits per plant (132.33) and yield per plant (8.47 kg) was recorded in T5 (cut tuber planted in cocopeat + vermicompost). Seedlings (T7) recorded the highest number of tubers per plant (11.22). Whereas, tuber yield per plant was the highest in T6 (whole tuber planted in soil + cocopeat + FYM) (790.10 g). The study revealed that basal cutting treated with 250 ppm IBA and planted in cocopeat + vermicompost (1:1) media as well as cut tubers in soil + cocopeat + FYM were found to be the best for production of quality planting material in teasel gourd. The plants propagated through tubers were superior in growth and yield attributes under field condition.
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    Integrated weed management in blackgram [Vigna mungo (L.) Hepper] with pre-mix herbicides.
    (Department of Agronomy, College of Agriculture, Vellayani, 2025-05-05) Ameena, M
    An investigation entitled ‘Integrated weed management in blackgram [Vigna mungo (L.) Hepper] with pre-mix herbicides’ was conducted at College of Agriculture, Vellayani during 2022-2024. The major objective was to formulate an integrated weed management strategy using pre-mix herbicides for black gram intercropped in coconut garden. The field experiment was conducted at the Instructional Farm, Vellayani during the summer season from February to April 2024 in a coconut garden with palms above 40 years of age. The experiment was laid out in randomized block design with nine treatments replicated thrice. The weed management practices tested were: T1- pre emergence (PE) pendimethalin + imazethapyr (premix 1) 800 g ha-1; T2 - T1 followed by (fb) hand weeding (HW) at 30 days after sowing (DAS); T3- post emergence (PoE) propaquizafop + imazethapyr (premix 2) 125 g ha-1; T4- T3 fb HW at 40 DAS; T5- PE pendimethalin 1kg ha-1 fb HW at 30 DAS; T6- PE pendimethalin 1kg ha-1fb PoE imazethapyr 50g ha-1; T7- PE pendimethalin 1kg ha-1 fb PoE propaquizafop 100g ha- 1; T8- HW at 15 and 30 DAS; T9- weedy check. The blackgram variety DBGV-5 treated with Bradyrhizobium inoculant BMBS 47 was dibbled in the interspaces of coconut and managed as per the KAU Package of Practices. Pre emergence herbicide was applied on the next day of sowing and post emergence applied at 15 DAS. Symptoms of phytotoxicity were observed in crop as mild stunting in plots sprayed with premix combination, pendimethalin + imazethapyr which persisted upto 10 days after herbicide application. The results of the study revealed that weed management practices had no significant influence on the growth attributes of blackgram. However, the yield and yield attributes were significantly influenced by the weed management practices. Higher pods per plant was recorded in T4 (36.00) and was comparable with T7 (35.83) while weedy check recorded the lowest number of pods (14.24). Hundred seed weight was recorded higher in T2 (5.33 g) and was on par with T4 (5.17 g) and T1 (5.13 g). The highest seed yield per plant was recorded in T4 (9.60 g) followed by T7 (9.23g), T6 (8.3g) and T5 (8.23g). Post emergence application of premix 2 fb HW at 40 DAS resulted in higher seed yield per ha (1793 kg) and was comparable with T7 (1731 kg). Higher haulm yield per ha was recorded in T5 (3658 kg) and was comparable with T4 (3616 kg), T6 (3581 kg) and T7 (3485 kg). The study observed that absence of weeding led to the highest yield reduction in blackgram, with a weed index of 54.44 per cent while yield reduction was lower in T4 (2.45%) and on par with T7 (5.35%). The predominant weed flora in the experimental field was grasses. However, more diversity was observed in the flora of broad leaf weeds. Pre emergence application of premix 1 fb HW at 30 DAS resulted in significantly lower weed density and weed dry weight and higher weed control efficiency at all stages of observation and was comparable with T7, T4 and T6. At 30 and 45 DAS, T1, T2, T5, T6 and T7 resulted in lower relative biomass of grasses that was comparable with T4 and the highest relative biomass of grasses was recorded in weedy check (85.92 %). Treatments involving both pre- and post-emergence herbicide applications (T7 and T6) resulted in higher dehydrogenase enzyme activity at 30 DAS, while their combination with hand weeding (T4, T5) showed increased activity at 45 DAS. Weed management practices significantly influenced nutrient uptake, with T7 and T1 exhibiting higher N, P and K uptake. The integration of premix herbicides with hand weeding and use of pre and post-emergence herbicides, significantly reduced N, P, and K removal by weeds throughout the growth period. The BC ratio varied significantly among the weed management practices with the highest in T4 (1.95), followed by T7 (1.94), with the lowest ratios in hand weeding twice (1.05) and weedy check (0.82). Weed management practices significantly influenced the population of Bradyrhizobium, fungi and actinomycetes in rhizospheric soil at 30 DAS with T2 showing higher count and on par with T1. However, no significant differences were noted in the population of phosphorus solubilising bacteria across all time points. The in vitro sensitivity test of Bradyrhizobium to premix 1 and 2 at concentrations of 800 to 2000 ppm and 175 to 325 ppm respectively showed positive growth with no inhibition zones around the sterile disc containing herbicide mixture placed on a lawn of Bradyrhizobium in the medium. The study identified application of propaquizafop + imazethapyr 125 g ha-1 at 15 DAS fb HW at 40 DAS; and application of pendimethalin 1kg ha-1 on the next day of sowing fb propaquizafop 100g ha-1 at 15 DAS as the most effective weed management strategies in terms of yield, weed control efficiency and gross return in blackgram. Considering economics, application of propaquizafop + imazethapyr at 15 DAS fb HW at 40 DAS could be adjudged as the most effective integrated weed management strategy for achieving higher seed yield in blackgram intercropped in coconut garden.
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    Performance of intercrops and weed suppression in paired row planted rice in low land summer fallows
    (Department of Agronomy, College of Agriculture, Vellayani, 2025) Hemand, J.
    A field experiment entitled “Performance of intercrops and weed suppression in paired row planted rice in low land summer fallows” was conducted at Department of Agronomy, College of Agriculture, Vellayani and Integrated Farming System Research Station, Karamana, Thiruvananthapuram, Kerala, during 2022 to 2024. The main objective was evaluation of intercrops in paired row planted rice in summer fallows of double cropped lowland rice field, in terms of weed dynamics, biological efficiency and economics. The field experiment was conducted during summer season of 2023-24 at Integrated Farming System Research Station (IFSRS), Karamana, Thiruvananthapuram, Kerala, India. The field experiment was laid out in randomized complete block design with ten treatments and three replications. The treatments were T1: Paired row of rice + grain cowpea, T2: Paired row of rice + finger millet, T3: Paired row of rice + Foxtail millet, T4: Paired row of rice + proso millet, T5: Sole crop of paired row rice, T6: Sole crop of grain cowpea, T7: Sole crop of finger millet, T8: Sole crop of foxtail millet, T9: Sole crop of proso millet, T10: Fallow. The varieties used for the study for rice, grain cowpea, finger millet, foxtail millet and proso millet were Uma, Bhagyalekshmi, Co 15, Co (Te)7 and TNAU 202, respectively. FYM and fertilizers were applied as per the recommendations (KAU, 2024 and TNAU, 2024) to rice, grain cowpea and millets, respectively. The growth attributes of rice and intercrops were recorded at monthly intervals. The analyzed data revealed that growth attributes of rice were significantly influenced by treatments. Among the treatments, the higher number of tillers m-2, and leaf area index were in sole crop of paired row rice (T5). Among the yield attributes, rice recorded the highest number of productive tillers m-2, grain yield and straw yield in the sole crop treatment(T5). The analyzed data showed that T5 recorded 8 to 15 per cent yield increase over intercropping treatments. The highest harvest index (0.48) of rice was obtained when intercropped with finger millet (T2). Sole crop of grain cowpea (T6) recorded the highest growth attributes when compared to intercropped treatments. Among the yield and yield attributes, number of pods per plant (15.87), grain yield (4526 kg ha-1), haulm yield (4526 kg ha-1) and harvest index (0.43) were the highest in sole crop of grain cowpea (T6). Analyzed data revealed that the plant height and number of tillers of finger millet, foxtail millet and proso millet were significantly influenced by intercropping treatments. The highest mean plant height and number of tillers m-2 were recorded in their sole crops. The sole crop yield of finger millet, foxtail millet and proso millet were higher than their intercropping treatments. Grasses were the predominant weed flora in the field. Total weed count and weed dry weight were significantly influenced by treatments. At 15 DAS, weed smothering efficiency (WSE) was highest in T4 (44.94%), while at 30 DAS and at 45 DAS, the highest efficiency of 43.79 and 40.57 per cent, were recorded in T1. The results on nutrient removal by weeds showed that significantly lower N, P and K were removed by weeds in T1 (Paired row of rice + grain cowpea). Total NPK uptake of crops were also influenced by the treatments. Higher nutrient uptake of all crops was seen in their sole cropping treatments. In rice, P uptake was significantly influenced by the treatments. The results on soil data revealed that the dehydrogenase activity (150.89 μg TPF g-1 soil d-1) was the highest in T1.The available N and P was higher in T6 and available K was higher in T9. The LER value was greater than unity in all intercropping treatments. Among the intercropping treatments, the highest RCC was observed in T1. Product of RCC was greater than one in all treatments. Aggressivity values were found positive in rice and negative in intercrops. Results indicated that rice equivalent yield from all intercropping system was significantly higher than sole crop of rice except in intercropping with proso millet. Highest monetary advantage was obtained from T1. Higher BCR and net income was observed in T1 (Rice + grain cowpea). Results revealed that net income of T1 was 39.27% higher than T5. The study on the performance of various intercrops in paired row planted rice in lowland summer fallows revealed that paired row planted rice intercropped with grain cowpea can be adjudged as the best treatment in case of weed control, biological efficiency and had higher net income and BCR.
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    Performance of intercrops and weed suppression in paired row planted rice in low land summer fallows
    (Department of Agronomy, College of Agricultuture,Vellayanire , Vellayani, 2025-02-04) Hemand, J; Jacob John
    A field experiment entitled “Performance of intercrops and weed suppression in paired row planted rice in low land summer fallows” was conducted at Department of Agronomy, College of Agriculture, Vellayani and Integrated Farming System Research Station, Karamana, Thiruvananthapuram, Kerala, during 2022 to 2024. The main objective was evaluation of intercrops in paired row planted rice in summer fallows of double cropped lowland rice field, in terms of weed dynamics, biological efficiency and economics. The field experiment was conducted during summer season of 2023-24 at Integrated Farming System Research Station (IFSRS), Karamana, Thiruvananthapuram, Kerala, India. The field experiment was laid out in randomized complete block design with ten treatments and three replications. The treatments were T1: Paired row of rice + grain cowpea, T2: Paired row of rice + finger millet, T3: Paired row of rice + Foxtail millet, T4: Paired row of rice + proso millet, T5: Sole crop of paired row rice, T6: Sole crop of grain cowpea, T7: Sole crop of finger millet, T8: Sole crop of foxtail millet, T9: Sole crop of proso millet, T10: Fallow. The varieties used for the study for rice, grain cowpea, finger millet, foxtail millet and proso millet were Uma, Bhagyalekshmi, Co 15, Co (Te)7 and TNAU 202, respectively. FYM and fertilizers were applied as per the recommendations (KAU, 2024 and TNAU, 2024) to rice, grain cowpea and millets, respectively. The growth attributes of rice and intercrops were recorded at monthly intervals. The analyzed data revealed that growth attributes of rice were significantly influenced by treatments. Among the treatments, the higher number of tillers m-2, and leaf area index were in sole crop of paired row rice (T5). Among the yield attributes, rice recorded the highest number of productive tillers m-2, grain yield and straw yield in the sole crop treatment(T5). The analyzed data showed that T5 recorded 8 to 15 per cent yield increase over intercropping treatments. The highest harvest index (0.48) of rice was obtained when intercropped with finger millet (T2). Sole crop of grain cowpea (T6) recorded the highest growth attributes when compared to intercropped treatments. Among the yield and yield attributes, number of pods per plant (15.87), grain yield (4526 kg ha-1), haulm yield (4526 kg ha-1) and harvest index (0.43) were the highest in sole crop of grain cowpea (T6). Analyzed data revealed that the plant height and number of tillers of finger millet, foxtail millet and proso millet were significantly influenced by intercropping treatments. The highest mean plant height and number of tillers m-2 were recorded in their sole crops. The sole crop yield of finger millet, foxtail millet and proso millet were higher than their intercropping treatments. Grasses were the predominant weed flora in the field. Total weed count and weed dry weight were significantly influenced by treatments. At 15 DAS, weed smothering efficiency (WSE) was highest in T4 (44.94%), while at 30 DAS and at 45 DAS, the highest efficiency of 43.79 and 40.57 per cent, were recorded in T1. The results on nutrient removal by weeds showed that significantly lower N, P and K were removed by weeds in T1 (Paired row of rice + grain cowpea). Total NPK uptake of crops were also influenced by the treatments. Higher nutrient uptake of all crops was seen in their sole cropping treatments. In rice, P uptake was significantly influenced by the treatments. The results on soil data revealed that the dehydrogenase activity (150.89 μg TPF g-1 soil d-1) was the highest in T1.The available N and P was higher in T6 and available K was higher in T9. The LER value was greater than unity in all intercropping treatments. Among the intercropping treatments, the highest RCC was observed in T1. Product of RCC was greater than one in all treatments. Aggressivity values were found positive in rice and negative in intercrops. Results indicated that rice equivalent yield from all intercropping system was significantly higher than sole crop of rice except in intercropping with proso millet. Highest monetary advantage was obtained from T1. Higher BCR and net income was observed in T1 (Rice + grain cowpea). Results revealed that net income of T1 was 39.27% higher than T5. The study on the performance of various intercrops in paired row planted rice in lowland summer fallows revealed that paired row planted rice intercropped with grain cowpea can be adjudged as the best treatment in case of weed control, biological efficiency and had higher net income and BCR.
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    Integrated weed management in finger millet (Eleusine coracana L.)
    ( Department of Agronomy, College of Agriculture,Padannakadu, 2024-04-24) Keerthana, E.; Gayathri Karthikeyan, P.
    A field experiment was conducted entitled 'Integrated weed management in finger millet (Eleusine coracana L.)' to standardise weed management practice in finger millet and to assess the economics during the rabi season (2023) at the Instructional Farm II, Karuvacheri, College of Agriculture, Padannakkad; with 10 treatments and 3 replications. The treatments being T1 – pre-emergence application of bensulfuron methyl + pretilachlor @ 660 g ha-1 (PEM), T2 –T1 + Hand weeding (HW) at 20-25 DAS, T3 – T1 + mulching, T4 – T1 + post emergence application of bispyribac sodium @ 25 g ha-1 (POEM) at 20 DAS, T5 – POEM at 20 DAS + HW (40 DAS), T6 – mulching + POEM (20 DAS), T7 – mulching + HW (25 DAS), T8 – HW (20 and 40 DAS), T9 – mulching alone, T10 – weedy check/control. Higher value for plant height, number of tillers hill-1, leaf area index and total plant dry matter was recorded by PEM + POEM (T4) on par with PEM + mulching (T3). These treatments could also impart significant positive impact for different weed control parameters viz. weed density, weed dry weight and weed control efficiency (WCE). Highest grain yield (1333 kg ha-1) and straw yield (1926 kg ha-1) and lowest weed index was recorded by T4 on par to T3. Nitrogen uptake also recorded significant variation among the treatments. B: C ratio and net returns were comparable for T4 and T3. Pre-emergent herbicide application delayed the emergence of weeds during the initial period of crop growth and further weed emergence could be managed by the application of post emergent herbicide and mulching in T4 and T3 respectively. Even though chemical weed management delivered better results for various parameters, IWM was equally effective in managing diverse life cycles and survival strategies of weeds. Hence, pre-emergent application of bensulfuron methyl + pretilachlor followed by mulching could be recommended as an effective weed management strategy for finger millet as sole dependence on herbicides may lead to excess use, resistance development etc. Hand weeding at 20 and 40 DAS was also proved to be an effective weed management strategy in finger millet. However, cannot be recommended as it is not economically feasible due to high cost of labour.
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    Eco-Friendly Weed Management in Okra (Abelmoschus Esculentus (L.) Moench)
    (Department Of Agronomy College Of Agriculture, Vellayani, 2021-10-13) Seethal Rose Chacko; Sheeja K Raj
    The study entitled “Eco-friendly weed management in okra (Abelmoschus esculentus (L.) Moench) was carried out during the period 2019-2021, at College of Agriculture, Vellayani, Thiruvananthapuram, Kerala with an objective to find out a cost -effective ecofriendly weed management practice for okra. The field experiment was conducted at Coconut Research Station, Balaramapuram, Thiruvananthapuram, Kerala during Rabi 2020 (November 2020- March 2021). The experiment was laid out in randomized block design with 12 treatments replicated thrice. The treatments were combinations of two factors, first factor being seedbed preparation (S), viz., stale seedbed (S1) and normal seedbed (S2) and second factor, weed management practices (W) viz., dried banana leaf mulch @ 10 t ha-1 alone (W1), dried banana leaf mulch @10 t ha-1 fb mechanical weeding (MW) with wheel hoe weeder (WHW) at 30 DAS and 45 DAS (W2), dried banana leaf mulch @10 t ha-1 fb hand weeding (HW) at 30 and 45 DAS (W3), MW with WHW at 15, 30 and 45 DAS (W4), HW at 15, 30 and 45 DAS (W5) and weedy check (W6). The variety used for the study was Anjitha. Results of the experiment revealed that seedbed preparation had significant influence on growth parameters, physiological parameters, yield attributes and quality parameters in okra and higher values were recorded in SSB. At 15, 30 and 60 DAS, lower total density of weeds (30.44, 90.67 and 35.67 no. m-2), weed dry weight (0.139, 4.57 and 7.81 g m-2) and higher weed control efficiency (WCE) (80.20, 89.46 and 81.33%) were recorded in SSB compared to normal seedbed. The highest nutrient uptake by crop, dehydrogenase enzyme activity at 60 DAS and urease enzyme activity at 15, 30 and 60 DAS and the lowest nutrient removal by weeds at 30 and 60 DAS were recorded in SSB. Higher net income (54,520 ₹ ha-1) and B:C ratio (1.69) were recorded in SSB compared to normal seedbed (non-stale). Higher values for growth parameters viz., plant height, number of branches per plant, number of leaves per plant, dry matter production and physiological parameters such as LAI, total chlorophyll content at 60 DAS and CGR at 30-60 DAS time interval were recorded in MW with WHW at 15, 30 and 45 DAS (W4). However, the treatment W5 (HW at 15, 30 and 45 DAS) resulted in the highest total chlorophyll content at 30 DAS and W2 (dried banana leaf mulch @ 10 t ha-1 fb MW at 30 and 45 DAS) resulted in the highest CGR during 60 DAS-final harvest. Mechanical weeding with WHW at 15, 30 and 45 DAS recorded greater number of fruits per plant (38.8 no. per plant), higher fruit girth (6.36 cm), fruit length (15.20 cm), fruit weight (6.98 g), dry haulm yield per plant (63.51 g), dry haulm yield per hectare (2353 kg ha-1), fruit yield per plant (0. 270 kg) and fruit yield per hectare (4412 kg ha-1) and the lowest weed index. Quality parameters such as crude protein and ascorbic acid content was higher in treatment W2 (dried banana leaf mulch @ 10 t ha-1 fb MW at 30 and 45 DAS). The lowest total weed density at 60 DAS (26.67 no. m-2), the lowest total weed dry weight at 30 and 60 DAS (2.48 and 2.54 g m-2, respectively) and the highest WCE at 30 and 60 DAS (92.28 and 93.86 %, respectively) were recorded in MW with WHW at 15, 30 and 45 DAS (W4). The highest nutrient uptake by crop and the lowest nutrient removal by weeds was recorded in the treatment W4. The highest net income (97,804 ₹ ha-1) and B: C ratio (2.24) were recorded in W4 (MW with WHW at 15, 30 and 45 DAS). Interaction between seedbed preparation and weed management practice was significant only for plant height at 60 DAS and final harvest, DMP at 30 and 60 DAS, LAI at 60 DAS and CGR at 30-60 DAS and total weed density, weed dry weight, WCE and nutrient removal by weeds at 30 and 60 DAS. Stale seedbed fb MW with WHW resulted in the lowest total weed dry weight and the lowest nutrient removal by weeds. Considering the growth, yield, weed control efficiency, nutrient removal by weeds, nutrient uptake by crop and economics, it could be concluded that in SSB or in normal seedbed (non-stale), mechanical weeding with wheel hoe weeder at 15, 30 and 45 DAS could be adjudged as the best ecofriendly weed management practice for higher yield and net income in okra
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    Integrating weed management with nano nitrogen in okra(Abelmoschus esculentus(L.) moench)
    (Department of agronomy, college of agriculture, Vellayani, 2023-09-21) Navaneetha, C; Ameena, M
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    Integrating weed management with nano nitrogen in okra(Abelmoschus esculentus(L.) moench)
    (Department of agronomy, collegeof agriculture ,Vellayani, 2023-09-21) Navaneetha, C; Ameena, M
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    Allelopathy for weed management in field crops
    (Department of Agronomy, College of Agriculture , Vellanikkara, 2022) Shakkira, K K; Sindhu, P V
    Weeds have been a persistent menace for farmers since the advent of agriculture. Among several methods adopted for controlling weeds, chemical control is the widely used and most effective. However, the extensive use of herbicides has led to the generation of a wide range of problems including development of herbicide resistant weeds. As a result, extensive research is being done to exploit non chemical methods of weed management. The mechanism of allelopathy has been suggested as a potential biorational method towards this goal. Hence the present study entitled “Allelopathy for weed management in field crops” was conducted during February-October 2021 in the Department of Agronomy, College of Agriculture, Vellanikkara, Kerala Agricultural University, Thrissur. The study consisted of two parts viz., screening Andrographis paniculata, Plectranthus ambonicus and Tagetes minuta for their allelopathic potential, and evaluating alleloapathic effect of these plant extracts on weeds and the test crops rice, cowpea and green gram. Cold water, hot water and methanol extracts of these plants were prepared at six concentrations viz., 5 %, 10 %, 15 %, 20 %, 25 % and 30 % in a completely randomized design (CRD) in factorial arrangement with three replications. In the first experiment plants were screened for their allelopathic potential against upland weeds in 165 plastic trays (25 cm x 20 cm x 5 cm) that were filled to three-quarters with uniform quantity of soil (1.5 kg) collected from an open area. Best 10 treatment combinations from this experiment and a control with distilled water were carried over to the second experiment. The second experiment consisted of two parts; in petri plates to test the phytotoxic activity on test crops (cowpea, green gram and rice) and in pot culture study with test crops and weeds. Both studies were carried out in completely randomized design (CRD) in factorial arrangement with two factors and three replications. Factor A consisted of time of application (on the day of sowing and 6th day after sowing). Factor B consisted of the best 10 allelopathic treatments from experiment 1. Experiment on screening allelopathic plants for their potential to control upland weeds revealed the significant influence of the plants, the method of extraction and the concentration of extract on weed growth parameters such as weed density and weed dry weight. Broad leaved weeds were more sensitive to allelopathic extracts than grass weeds. Reduction in weed germination count and dry weight after one month of application was noticed with methanol extract of Tagetes minuta at 30 per cent concentration and was 6.67 nos./m2 and 21. 33 g/m2 respectively as compared to control (68.33 nos./m2 and 54. 25 g/m2 ). Pre mergence application of Andrographis paniculata methanol extract at 30 per cent concentration was the next best treatment. Allelopathic effect of plants was significant only for a short period of time i.e. up to one week after application, indicating absence of residual action. Germination indices and seedling growth parameters of test crops were adversely affected by the application of allelopathic extracts. Among test crops, cowpea and green gram were more sensitive to allelopathic extracts than rice. A notable delay in germination of test crops, in shoot and root length, and in fresh and dry weights were observed by the application of allelopathic treatments. Phytotoxicity symptoms were observed on test crops both under laboratory condition and in pot culture. Root decay and reduction in number of rootlets were observed by the pre emergence application of 30 and 25 per cent methanol extract of Tagetes minuta. When Tagetes minuta methanol extract was applied at 30 or 25 per cent as pre mergence treatment, germination of cowpea and green gram started on the 4th and 5th day after sowing as compared to the 2nd day in control. Root length reduction was more pronounced than shoot length reduction. The reduction was 43.29 and 41.46 per cent in cowpea, and 41.56 and 37.05 per cent in green gram, due to pre emergence application of 30 and 25 per cent methanol extract of Tagetes minuta in petri plates. In pot culture study, root reduction of 70.85 and 71.01 per cent in cowpea and green gram by the pre emergence application of 30 per cent methanol extract of Tagetes minuta as was observed. A notable delay in weed germination and weed dry weight reduction were observed by 30 and 25 per cent Tagetes minuta methanol extract applied as pre emergence treatment and their residual inhibitory effect in the soil persisted up to one week. Based on the results of the study, pre emergence application (on the day of sowing) of methanol and cold water extracts of Tagetes minuta and Andrographis paniculata at 30 per cent concentration can be recommended for control of broad leaved weeds in uplands.