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Assam Agricultural University, Jorhat

Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.

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2019 - 201912020 - 20231
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Subject: Agronomy × Author: PHUKAN, JIMNI × Start date: 2010 ×
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    ThesisItemOpen Access
    EVALUATION OF TILLAGE, PLANT GROWTH PROMOTING BACTERIA AND WEED MANAGEMENT PRACTICES IN UPLAND DIRECT SEEDED RICE
    (2023) PHUKAN, JIMNI; Deka, Jayanta
    A field experiment entitled “Evaluation of tillage, plant growth promoting bacteria and weed management practices in upland direct seeded rice” was carried out during 2020 and 2021 at Instructional-Cum-Research (ICR) Farm, Assam Agricultural University, Jorhat to evaluate the effect of different tillage, plant growth promoting bacteria and weed management practices on weed, crop and soil properties. The experiment comprising 20 treatment combinations with 2 tillage practices, viz., T1: conventional tillage, T2: reduced tillage up to 50%; 2 plant growth promoting bacteria treatments, viz., P1: Pseudomonas fluorescens, P2: no inoculation and 5 weed management practices, viz., W1: Sesbania aculeata mulching, W2: brown manuring with Sesbania aculeata, W3: pretilachlor @ 0.75 kg/ha followed by bispyribac-sodium @ 0.025 kg/ha at 30 DAS, W4: mechanical weeding at 20 and 40 DAS, W5: weedy check, laid out in a split-plot design with tillage and plant growth promoting bacteria treatments in main plot and weed management practices in sub-plots replicated thrice. The soil of the experimental site was sandy loam, acidic in reaction (pH 5.5), medium in organic carbon (0.60 %), available N (280.60 kg/ha), available P2O5 (22.28 kg/ha) and low in available K2O (128.07 kg/ha). The initial bulk density, total porosity as well as water holding capacity of the soil at 0-15 and 15-30 cm soil depth were 1.43 and 1.50 g/cc, 44.96 and 42.31% and 43.10 and 41.02 %, respectively. Among tillage practices, conventional tillage resulted in the lower weed growth throughout the crop growth period and the higher crop growth characteristics as well as yield parameters of upland direct seeded rice as compared to reduced tillage up to 50%. The per cent increase in grain yield of upland direct seeded rice under conventional tillage over reduced tillage up to 50% were to the tune of 16.60 and 17.91 in 2020 and 2021, respectively. Among, plant growth promoting bacteria treatments, Pseudomonas fluorescens inoculation recorded better crop growth characteristics as well as yield parameters leading to better weed suppression as compared to no inoculation. The per cent increase in grain yield under Pseudomonas fluorescens inoculation compared to no inoculation was to the tune of 8.38 in 2020 and 8.84 in 2021. Among different weed management treatments, pretilachlor @ 0.75 kg/ha followed by bispyribac-sodium @ 0.025 kg/ha at 30 DAS and brown manuring with Sesbania aculeata recorded the lower weed growth and nutrient uptake by weeds with higher WCE and WCI during active crop growth period which resulted into the higher crop growth characteristics and yield parameters ultimately reflecting in the higher grain and straw yields with higher nutrient uptake by the crop. The corresponding per cent increase in grain yield of crop in pretilachlor @ 0.75 kg/ha followed by bispyribacsodium @ 0.025 kg/ha at 30 DAS and brown manuring with Sesbania aculeata compared to weedy check was 188.99 and 175.62 in 2020 and 189.24 and 174.85 in 2021, respectively. Treatment combination of conventional tillage either with pretilachlor @ 0.75 kg/ha fb bispyribac-sodium @ 0.025 kg/ha at 30 DAS or brown manuring with Sesbania aculeata recorded higher grain and straw yields as compared to other treatment combinations. Soil physico-chemical and biological properties like carbon stock, periodical soil moisture content, available N, P2O5 and K2O, microbial population, microbial biomass carbon and maximum activity of enzymes, viz., phosphomonoesterace and dehydrogenase was recorded in reduced tillage up to 50% compared to conventional tillage. However, bulk density, total porosity and water holding capacity were better under conventional tillage. Among plant growth promoting bacteria treatments, Pseudomonas fluorescens inoculation recorded higher availability of nutrients, microbial population, microbial biomass carbon and maximum activity of enzymes, viz., phosphomonoesterace and dehydrogenase. However, this treatment did not significantly affect the soil physical properties. The higher B-C ratio was recorded under treatment combination of conventional tillage, Pseudomonas fluorescens with pretilachlor @ 0.75 kg/ha fb bispyribac-sodium @ 0.025 kg/ha at 30 DAS (2.01 and 2.04) followed by conventional tillage, Pseudomonas fluorescens and brown manuring with Sesbania aculeata (1.97 and 2.01) in 2020 and 2021, respectively.
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    ThesisItemOpen Access
    EFFECT OF PLANT GROWTH-PROMOTING RHIZOBACTERIA AND WEED MANAGEMENT IN DIRECT-SEEDED UPLAND RICE
    (AAU, Jorhat, 2019-07) PHUKAN, JIMNI; Deka, Jayanta
    A field experiment entitled “Effect of Plant Growth-promoting Rhizobacteria and Weed Management in Direct-seeded Upland Rice” was carried out at Instructional-cum-Research Farm (ICR), Assam Agricultural University, Jorhat during autumn season of 2018 with a view to study the effect of plant growth-promoting rhizobacteria and weed management practices on weed, crop growth and yield of direct seeded upland rice. The experiment was laid out in factorial randomized block design with three replications. The treatments consisted of three PGPR inoculations viz., Bacillus cereus (P1), Pseudomonas fluorescens (P2) and no inoculation (P3) and four weed management practices viz., Pretilachlor @ 0.75 kg/ha (W1), Pretilachlor @ 0.75 kg/ha followed by 1 hand weeding at 30 DAS (W2), three hand weedings at 15, 30 & 45 DAS (W3) and weedy check (W4). The soil of the experimental site was sandy loam, acidic in reaction (pH: 5.5), medium in organic carbon (0.54%), low in available N (191.0 kg/ha), P2O5 (22.28 kg/ha) and K2O (107.05 kg/ha). The weed flora of the experimental field comprised of Eleusine indica, Digitaria setigera, Cynodon dactylon, Cyperus difformis, Cyperus rotundus, Ageratum houstonianum, Commelina diffusa, Oldenlandia corymbosa, Spermacoce articularis, Cleome rutidosperma, Mimosa pudica and Acmella ciliata. The density and dry weight of weeds were lowest with Pseudomonas fluorescens among PGPR treatments. The plant height, number of tillers, plant dry matter accumulation, panicle length, number of panicles and number of grains were significantly improved due to Pseudomonas fluorescens. The highest grain and straw yield of rice were recorded with Pseudomonas fluorescens. Bacterial populations in soil, phosphomonoesterace and dehydrogenase activity were enhanced by Pseudomonas fluorescens but fungal population in soil was increased by Bacillus cereus. Single application of Pretilachlor @ 0.75 kg/ha or application of Pretilachlor @ 0.75 kg/ha followed by 1 hand weeding at 30 DAS resulted least density and dry weight of weeds at initial stages but in later stages of crop growth, lowest values were recorded in three hand weedings done at 15, 30 & 45 DAS. Better growth and yield attributing characters of rice with three hand weedings at 15, 30 & 45 DAS resulted in the highest grain and straw yields. Higher microbial count in soil and enzymatic activity were recorded in weedy check and three hand weedings at 15, 30 & 45 DAS. The combination of Pseudomonas fluorescens with either three hand weedings at 15, 30 & 45 DAS or Pretilachlor @ 0.75 kg/ha followed by 1 hand weeding at 30 DAS was found to be superior with grain and straw yield. Similar trend was also achieved in gross and net returns. The benefit : cost ratio was highest with the combination of Pseudomonas fluorescens with Pretilachlor pre-emergence @ 0.75 kg/ha followed by 1 hand weeding at 30 DAS.