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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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Subject: Agronomy × Author: Beypi, Mirdan × End date: 2023 × Start date: 2020 ×
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    ThesisItemOpen Access
    EFFICACY OF HERBICIDE COMBINATIONS FOR WEED MANAGEMENT IN DIRECT SEEDED KHARIF RICE
    (2023) Beypi, Mirdan; Kalita, Sontara
    A field experiment entitled “Efficacy of herbicide combinations for weed management in direct seeded kharif rice” was carried out in Instructional-cum-Research farm, Assam Agricultural University, Jorhat during kharif, 2022.The Randomized Block Design was used to arrange 12 weed management treatments in 3 replications. The treatments were weed free (T1), weedy check (T2), bispyribac-sodium 25g/ha + pyrazosulfuron 20g/ha 20 days after sowing (DAS) as check (T3), pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4), pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5), pretilachlor 750g/ha pre-emergence followed by penoxsulam 30 g/ha + bentazone 1080 g/ha 20 DAS (T6), glyphosate 1000 g/ha followed by one mechanical weeding 30 DAS (T7), glyphosate 1000 g/ha followed by fenoxaprop-p-ethly 50g/ha + ethoxysulfuron 15g/ha 20 DAS (T8), glyphosate 1000 g/ha followed by triafamone + ethoxysulfuron 60g/ha at 20 DAS (T9), glyphosate 1000g/ha followed by penoxsulam 30g/ha + bentazone 1080g/ha 20 DAS (T10), hand weeding at 20 DAS and weeding with grubber at 40 DAS (T11) and two mechanical weeding at 20 and 40 DAS (T12). The texture of the soil was sandy loam with pH of 5.5, bulk density of 1.40 Mg/m3, organic carbon of 0.67% and available N, P2O5 and K2O of 289.93, 19.69 and 114.11 kg/ha, respectively. All treatments significantly lowered the weed density as well as dry matter in terms of broad-leaved, sedge and grassy weeds at 60, 90 and 120 DAS and at harvest as compared to weedy check. Significant reduction (75.59, 56.97, 44.77 and 30.44 %, respectively) in density of total weeds was observed in treatment (T5) pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS at 60, 90 and 120 DAS as well as at harvest over weedy check. The same treatment recorded significantly lower dry matter of total weeds at 60, 90 and 120 DAS and at harvest to the tune of 73.39, 52.71, 37.76 and 27.46 %, respectively over weedy check. Pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) showed higher result with regards to crop growth parameters viz., plant height, number of tillers/m2, leaf area index, dry matter accumulation/m2 and crop growth rate at all the stages as compared to rest of weed management treatments except for plant height which was found to be not significant at 30, 120 DAS and at harvest. The above-mentioned treatment also showed higher result in terms of yield attributing characters viz., number of panicles/m2 and number of grains/panicle with 77.60 and 40.97 % increase over weedy check. In case of panicle length and test weight, the result was found to be not significant among all the treatments. Grain yield was found to be significantly higher in pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) with 175.16 % higher over weedy check and was at par with pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4). Similar result was observed in terms of straw and biological yield with 137.38 and 152.37 %, respectively increase over control. In case of straw yield (50.68 kg/ha) T5 was at par with T4 (46.65 kg/ha) and T6 (44.85 kg/ha). Weed management treatment did not significantly affect harvest index of direct seeded kharif rice. The lower weed index was recorded in pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) (5.84 %) followed by pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4) (13.30 %) and pretilachlor 750g/ha pre-emergence followed by penoxsulam 30 g/ha + bentazone 1080 g/ha 20 DAS (T6) (17.49%). No significant change in N, P and K content was recorded in grain and stover whereas N, P and K uptake by the crop was significantly higher in pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5). The mentioned treatment decreased N, P and K content in weeds and their uptake as compared to weedy check by 5.18, 22.08 and 6.78, and 50.18, 59.02 and 50.76 %, respectively over weedy check. The same treatment recorded higher available N, P2O5 and K2O by 7.55, 19.57 and 3.96 %, respectively over weedy check. Weed management treatment did not significantly affect soil organic carbon of direct seeded kharif rice. The highest gross and net returns (103541 and 62751 ₹ /ha, respectively) were noted by pretilachlor 750g/ha pre-emergence followed by triafamone + ethoxysulfuron 60g/ha 20 DAS (T5) along with the highest B-C ratio (1.54) closely followed by pretilachlor 750g/ha pre-emergence followed by fenoxaprop-p-ethyl 50 g/ha + ethoxysulfuron 15g/ha 20 DAS (T4) (1.36).