Browsing by Author "Poornima Yadav, P I"

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    Bioefficacy and residual effect of the new generation herbicide pyrazosulfuron ethyl in transplanted rice
    (Department of Agronomy, College of Agriculture, Vellayani, 2006) Poornima Yadav, P I; Elizabeth Syriac, K
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    Effect of seed soaking and foliar spray of growth regulators on rice (Oryza sativa L.)
    (Department of Agronomy, College of Agriculture, Vellayani, 2001) Poornima Yadav, P I; Babu Mathew, P
    A field experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani during the rabi 2000, to study the effect of seed soaking and foliar spray of growth and yield of rice. To assess the influence of different seed soaking chemicals on seed germination and seedling characters, a nursery study was conducted in CRD with four treatments and four replications (T1 –water soaking, T2 – soaking in Azospirillum, T3 – soaking in Penshibao, T4 – soaking in Azospirillum + Penshibao). The main field experiment was laid out in split split plot design with three replications. The treatments included four types of seed soaking (T1 – water soaking, T2 – soaking in Azospirillum, T3 – soaking in Penshibao, T4 – soaking in Azospirillum + Penshibao) in the main plots, five types of growth regulators as foliar spray (F1 – triacontanol, F2-GA3, F3-kinetin, F4-Penshibao and F5-water spray) in sub plots and two stages of application (S1-20 DAT and S2-20 and 30 DAT) in sub sub plots. Observations on nursey study revealed that soaking rice seeds in Azospirillum or Penshibao alone or in combination improved the germination percentage and all other seedling characters. Results of the main field experiment indicated that seed soaking, foliar spray, stages of application and their combinations had a significant influence on most of the growth characters, growth analysis parameters, yield attributing characters, yield, nutrient uptake and BCR. Soaking seeds in Penshibao + Azospirillum (T4), foliar spray with Penshibao (F4) and spraying at 20 and 30 DAT (S2) improved almost all growth characters, growth analysis parameters and chlorophyll content. These treatments also recorded the highest grain yield while straw yield was comparable for soaking in Penshibao alone and its combination with Azospririllum. Among the foliar sprays, Penshibao registered the highest grain and straw yield when applied at two stages compared to single application. In treatment combinations, soaking seeds in Azospirillum and Penshibao followed by foliar spray of Penshibao, soaking seeds in Penshibao followed by its foliar spray and soaking in Penshibao and Azospirillum followed by foliar spray of GA3 were found to be on par and significantly superior to other combinations. Nutrient uptake was also influenced by the three factors studied (seed soaking, foliar spray and stage of application). Nitrogen uptake was the highest for soaking seeds in Penshibao and Azospirillum and it was on par with soaking in Penshibao alone. Similarly foliar spray with Penshibao at 20 and 30 DAT registered the highest N uptake at harvest. The different chemicals used for seed soaking were found to have a comparable effect and superior to water soaking on P uptake. Among the combinations, soaking in Penshibao and Azospirillum with foliar spray of Penshibao at 20 and 30 DAT registered the highest values for N,P and K uptake. The economic analysis showed that the individual effect of combind soaking in Azospirillum (600 g ha-1) and Penshibao (100 ppm), foliar spray of Penshibao (100 ppm) and spraying at 20 and 30 DAT were superior to other treatments. Among the interactions, the treatment combination of soaking seeds in Penshibao + Azospirillum followed by foliar application of Penshibao at 20 and 30 DAT, recorded the highest BCR.
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    Performance of grain cowpea (Vigna unguiculata (L.) Walp.) in response to conservation tillage in the summer rice fallows of Onattukara sandy plains
    (Department of Agronomy, College of Agriculture, Vellayani, 2025-02-22) Arya, A P; Poornima Yadav, P I
    The study entitled “Performance of grain cowpea (Vigna unguiculata (L.) Walp.) in response to conservation tillage in the summer rice fallows of Onattukara Sandy Plains” was undertaken at College of Agriculture, Vellayani, during 2022 2024 with an objective to assess the response of grain cowpea varieties under conservation tillage and to work out the economics of cultivation. The field experiment was carried out at Onattukara Regional Agricultural Research Station, Kayamkulam under Onattukara Sandy Plains (AEU-3)’ from February to April 2024. The experiment was laid out in split plot design with four replications. The main plot treatments were three tillage options (T) viz., T₁ - Zero tillage + herbicides (pre plant application of glufosinate ammonium @ 0.375 kg ha 1 fb imazethapyr @ 50 g ha-1 at 15 DAS), T₂ - Minimum tillage + herbicide (imazethapyr @ 50 g ha-1 at 15 DAS) and T3- Conventional tillage. Sub plot treatments were three varieties viz., (V), Krishnamony (V₁), Hridya (V₂) and PGCP 6 (V3). The crop was managed according to the Package of Practices of KAU (2016) except land preparation and weed management. Under the treatment T1, the crop was sown in the residues of the previous crop without any prior soil tillage leaving the paddy stubbles as such. Under the treatment T2, the crop was sown after giving a shallow tillage which retained the paddy stubbles as mulch in the field. Hand weeding was done at 15 DAS in T3, conventional tillage. Cowpea seed was sown by dibbling at a spacing of 25 cm X 15 cm and recommended dose of nutrient @ 20:30:10 kg NPK ha-1 was applied as per KAU POP recommendations (KAU, 2016). The tillage options significantly influenced the growth attributes like plant height, number of primary branches per plant, and number of leaves per plant at 15 DAS, 30 DAS, 45 DAS and at harvest. Zero tillage + herbicides had higher values for all these parameters. Among the varieties, PGCP-6 resulted in taller plants at all stages of observation and higher number of leaves per plant at 45 DAS and at 140 harvest and primary branches per plant at harvest, while at 30 DAS and 45 DAS, the variety Hridya had more number of leaves and primary branches. The plants grown under zero-tillage + herbicides produced higher dry matter at 15 DAS, 30 DAS, 45 DAS and at harvest (0.31 g per plant, 4.58 g per plant, 22.19 g per plant and 29.84 g per plant, respectively). The variety PGCP-6 accumulated more dry matter at 30 DAS, 45 DAS and at harvest (5.34 g per plant, 26.84 g per plant and 37.17 g per plant, respectively) compared to other varieties. However, the interaction between tillage options and varieties was significant only at 30 DAS and the treatment t1v3 (PGCP-6 grown under zero-tillage) had higher dry matter accumulation (5.73 g per plant) than others. Number of pods per plant and hundred seed weight were significantly influenced by tillage options. The zero tillage + herbicides resulted in significantly higher number of pods per plant (18.24), hundred seed weight (8.70 g), pod yield per plant (17.86 g), seed yield per plant (9.50 g), haulm yield per plant (25.34 g), seed yield ha-1 (950 kg) and haulm yield ha-1 (3868 kg). Among the varieties, PGCP-6 resulted in the highest value for all yield parameters and yield viz., number of seeds per pod (15.18), pod length (17.26 cm), pod weight (2 g), and hundred seed weight (12.65 g). The pod yield per plant (17.39 g), seed yield per plant (9.94 g) haulm yield per plant (37.12 g), seed yield ha-1 (1254 kg), and haulm yield ha-1 (5666 kg) were also higher for the variety PGCP-6. Zero tillage + herbicides resulted in 13.5 per cent higher yield than conventional tillage. However, the interactions between tillage options and varieties were not significant for yield and yield attributes. Tillage options had a significant influence on rooting depth, root dry weight, and root volume and conventional tillage resulted in superior values. Zero tillage + herbicides resulted in lower values for these parameters. The variety PGCP-6 exhibited higher values for all root parameters studied. The nodule parameters like the total number of nodules per plant, nodule fresh weight, and effective nodules per plant were significantly influenced by tillage options at 30 DAS and zero tillage + herbicides showed higher values. Among the 141 varieties, PGCP-6 had higher values for the nodule parameters. The tillage option x variety interaction was significant and the variety PGCP-6 under zero tillage + herbicides had higher values for the nodule parameters. The effect of tillage options and varieties on weed density and weed dry matter was significant. At 15 DAS and 45 DAS, zero tillage + herbicides resulted in lowest weed density and weed dry weight. At 30 DAS conventional tillage recorded lower weed density and dry weight compared to other tillage options. Among the varieties, the weed incidence was lesser in PGCP-6. There was no significant interaction between tillage and varieties. The NPK uptake by plant was significantly affected by the treatments. The nutrient uptake was higher in zero tillage + herbicides. The variety PGCP-6 resulted in higher NPK uptake compared to other varieties. No significant interaction was observed between tillage options and varieties. At 15 DAS and 45 DAS, NPK removal by weeds was higher in conventional tillage. However, at 30 DAS, zero tillage + herbicides resulted in higher NPK removal by weeds. Among the varieties, nutrient removal by weeds was lesser in PGCP-6. At 45 DAS, dehydrogenase enzyme activity was higher in zero + herbicides and was on par with minimum tillage + herbicide. Among the varieties V2 (Hridya) and V3 (PGCP-6) recorded comparable values for soil dehydrogenase enzyme activity. At 30 DAS, urease enzyme activity was higher in zero tillage + herbicides. Among the tillage options, zero tillage + herbicides resulted in the highest net income (₹35653 ha-1) and benefit-cost ratio (1.70). Among the varieties, PGCP 6 registered higher net income (₹60027 ha-1) and benefit cost ratio (2.14). Considering the growth and yield as well as net income and benefit cost ratio, the grain cowpea variety PGCP-6 can be cultivated under zero tillage with herbicides (preplant application of glufosinate ammonium @ 0.375 kg ha-1 and post emergant herbicide imazethapyr @ 50 g ha-1 at 15 DAS) in the summer rice fallows of Onattukara Sandy Plains. It was found to be the most cost effective technology 142 for managing the weeds, a major production constraint in the in the summer rice fallows of Onattukara.
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    Silicon nutrition for rice in iron toxic laterite soils of Kollam district
    (Department of Agronomy, College of Agriculture, Vellayani, 2017) Guntamukkala Babu Rao; Poornima Yadav, P I