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Assam Agricultural University, Jorhat
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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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ThesisItem Open Access KNOWLEDGE AND PRACTICE OF ADOLESCENT GIRLS OF JORHAT DISTRICT OF ASSAM ON PERSONAL HYGIENE WITH SPECIAL REFERENCE TO MENSTRUAL HYGIENE(AAU, Jorhat, 2021) Chetia, Anwesha Bijoy; Sarmah, JulianaThe present investigation was conducted to study the “Knowledge and practice of adolescent girls of Jorhat district of Assam on personal hygiene with special reference to menstrual hygiene” with objectives : (i) To study the background profile of adolescent girls (ii) To assess the existing knowledge of respondents on personal hygiene with special reference to menstrual hygiene (iii) To identify the existing practice of respondents on personal hygiene with special reference to menstrual hygiene. The study was conducted in one Educational Block of Jorhat District of Assam namely Jorhat Educational Block. Twenty five (out of total 32 clusters) numbers of clusters having high school or higher secondary school were considered for the present study. As there are 20 clusters situated in rural area and 5 clusters are in the urban area, 50 per cent clusters of rural areas that is 10 nos. and 50 per cent clusters of urban areas that is 3 nos. were selected randomly for the present study. One high school or higher secondary school from each cluster was selected by using simple random sampling method. Thus, all total 13 numbers of high schools or higher secondary schools were considered for present study, 10 schools from rural and 3 schools from urban area were selected for the present study. From the total number, thirty percent girls belonging to 15 years to 19 years (late adolescent) were the respondents for the present study. Thus, all total 142 numbers of late adolescent girls (15-19 years of age belonging to class IX to XI) from the rural area and 112 numbers of late adolescent girls totaling 254 numbers of late adolescent girls from both rural and urban area of Jorhat district were the respondents for the present study to assess knowledge and practice of personal hygiene with special reference to menstrual hygiene. The study revealed that a higher percentage of respondents in both rural and urban area belonged to the age group of 15-17 years and respondents from both the areas respondents attained menarche at the age of 13-15 years. The study revealed that majority of the total respondents had no separate bathroom in their house for using during menstrual period. It is found that ‘menstrual hygiene’ is included in the syllabus of school. Majority of the respondent discussed about menstrual hygiene with their family. The findings showed that majority of the total respondents that nearly 53 per cent respondents had attended training on menstrual hygiene and remaining respondents who had not attended any training on menstruation were interested in obtaining training on menstruation. More than 36 per cent respondents had the menstrual cycle with the interval of 28 days. Nearly 78 per cent respondents did not consult with doctor if face any problem regarding menstruation and they did not use any local (indigenous) medicine during menstrual period. The study showed that higher percentage of respondents from both the rural and urban area had medium level of knowledge on personal hygiene with special reference to menstrual hygiene. The study also revealed that a higher percentage of overall respondents that is 69.29 per cent belonged to “moderate” category on menstrual hygiene practice. The study showed that there was highly positive significant relationship of menstrual hygiene knowledge with independent variable such as mass media exposure and there was positive significant relationship of menstrual hygiene knowledge with independent variable such as training attended. There was highly positive significant relationship of menstrual hygiene practice and independent variable such as size of the family and training attended. There was positive significant relationship of respondents’ knowledge on menstrual hygiene with their practice on menstrual hygiene in rural area.ThesisItem Open Access INTEGRATED NUTRIENT MANAGEMENT IN MANGO (Mangifera indica L.) CV. AMRAPALI(AAU, Jorhat, 2021) Mehta, Ritika; Gogoi, BornaliAn experiment entitled “Integrated nutrient management in mango (Mangifera indica) cv. Amrapali” was conducted during 2019-2021 at Experimental Farm, Department of Horticulture, Assam Agriculture University, Jorhat-13 with the objective to determine the effect of Integrated Nutrient Management (INM) on flowering, yield and biochemical constituents of mango and to determine the economics of cultivation. The experiment was laid out in Randomized Block Design with eight number of treatments which were replicated three times. The treatments are T0 : Absolute control, T1 : RDF (730 g N : 180 g P : 680 g K) + FYM plant-1, T2 : 75% RDF + FYM + Vermicompost (3 kg) + Azotobacter + PSB plant-1, T3: 50% RDF + FYM + Vermicompost (5 kg) + Azotobacter + PSB plant-1, T4: 75% RDF + FYM + Vermicompost (3 kg) +Azotobacter + PSB + Rock phosphate (100g) plant-1, T5: 50% RDF + FYM + Vermicompost (5 kg) + Azotobacter + PSB + Rock phosphate (200 g) plant-1, T6: 75% RDF + FYM + Enriched compost (3 kg) + Azotobacter + PSB plant-1, T7: 50% RDF + FYM + Enriched compost (5 kg) + Azotobacter + PSB plant-1. Azotobacter and PSB were applied 5 g each per kg of the compost and FYM was applied 20 kg per plant in every treatment from T1 to T7. Field data was taken for the two years i.e., 2019-2020 and 2020-2021 and the biochemical parameters were evaluated only during the year 2019-2020. During the first year of experiment, Days to 50% inflorescence emergence and Days to 50% flowering, were found to be non-significant. However, integrated application of nutrients had significant difference among each other during the second year of experiment. Pooled analysis over the two years revealed that the minimum days to 50% inflorescence emergence (133.58), minimum days to 50% flowering (143.24), maximum length of panicle (27.74 cm), number of rachis per branch (26.72), percentage of fruit set (33.34), fruit size (10.24 cm), yield per plant (14.60 kg) and pulp-peel ratio (6.31) were observed in T4. Percentage of fruit drop was also found to be lowest in treatment T4. Quality parameters like TSS (22.09º Brix), reducing sugar (4.94%), non-reducing sugar (12.15%) was found to be highest in T4. β carotene content was found to be maximum in treatment T2 which was statistically at par with treatment T4. Titratable acidity and crude fibre were found to be non-significant among the treatments. Results revealed that maximum available nitrogen (286.28 kg/ha), phosphorus (48.55 kg/ha), potassium (183.66 kg/ha) and organic carbon (0.99%) was found in treatment T4. pH among the treatments was observed to be non-significant. The net return and B:C ratio were found to be highest in treatment T4 followed by treatment T2. Thus, in a broader view, treatment T4 was better towards improving the flowering, yield and biochemical constituents of mango which is followed by treatment T2. Hence, considering the above points and based on results of experiment, treatment T4 [75% RDF + FYM (20 kg) + Vermicompost (3 kg) + Azotobacter (15 g) + PSB (15 g) + Rock phosphate (100 g) plant-1] is considered best for recommendation which is followed by treatment T2 [75% RDF + FYM (20 kg) + Vermicompost (3 kg) + Azotobacter (15 g) + PSB (15 g)] plant-1.ThesisItem Open Access Integrated nutrient management in lettuce (Lactuca sativa L.)(AAU, Jorhat, 2021) NATH, KANGKANA; Sarma, IraA field experiment was conducted at the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat during the year 2019-20 and 2020-21 to study the effect of integrated nutrient management on growth, yield and quality of lettuce. The experiment was laid out in a randomized block design (RBD) with eight treatments replicated thrice. The treatments were T1: Control, T2: 40:20:40 Kg NPK ha-1, T3: 40:20:40 Kg NPK ha-1+ FYM 2t ha-1, T4: 40:20:40 Kg NPK ha-1 +FYM 2t ha-1 + PSB, T5: FYM 3t ha-1+ PSB, T6: 40:20:40 Kg NPK ha-1 +VC 1t ha-1, T7: 40:20:40 Kg NPK ha-1 + VC 1t ha-1 +PSB and T8: VC 2t ha-1 + PSB. Observations of the growth parameters were taken at 30 days after planting (DAP), 45 days after planting (DAP) and at harvest. Analysis of variance during 2019-20, 2020-21 and across the years revealed significant mean square due to treatment for all the characters under study. The characters studied were plant height, leaves per plant, leaf length, leaf breadth, leaf canopy spread, leaf area, fresh weight, dry weight, days to marketable maturity, yield per plot and yield per hectare.The pooled analysis across 2019-20 and 2020-21 revealed that the treatment T7 recorded maximum plant height (14.25cm, 19.17cm and 26.92cm) and maximum leaves per plant (10.00, 17.17 and 29.17) at 30 DAP, 45 DAP and at harvest, respectively. The leaves per plant in the treatment T4 (9.88) at 30 DAP was statistically at par with treatment T7. Maximum leaf length (16.33cm, 22.67cm and 27.64cm) and leaf breadth (16.08cm, 22.17cm and 27.67cm) were exhibited by the treatment T7 at all the three growth stages. Leaf length in the treatments T4 (16.00cm) and T6 (15.48cm) were statistically at par with treatment T7 at 30 DAP. Maximum leaf canopy spread (12.6cm, 21.33cm and 29.75cm) and maximum leaf area (198.95cm², 347.29cm² and 543.33cm²) were observed in the treatment T7 at 30 DAP, 45 DAP and at harvest, respectively. Maximum fresh weight of leaves (206.33g) as well as dry weight of leaves per plant (13.85g) were exhibited by the treatment T7 whereas, minimum of these were recorded by the treatment T1. The highest yield (27.5 t/ha) was exhibited by the treatment T7. Minimum number of days to reach the marketable maturity was observed in the treatments T4 and T7 with values 53 days whereas maximum number of days (63 days) for the same character was observed in the treatment T1. The highest moisture content (96.28 %) was observed in the treatment T6. The integrated application of organic, inorganic and biofertilizers influenced the nutritional content of lettuce significantly. The ascorbic acid content (3.76mg/100g), calcium content (20.67mg/100g), non-reducing sugar content (3.98 %) and chlorophyll content (3.77mg/100g) were recorded maximum in treatment T7 whereas the maximum iron content (1.50 mg/100g) was observed in the treatment T5.The highest nitrogen (0.23%) and the crude protein content (1.44%) were observed in both the treatments T6 and T7. Maximum reducing sugar content was observed in T4. The highest net return (Rs. 192703.00) was obtained in the treatment T7 with benefit cost ratio 2.34. However, the highest benefit cost ratio was exhibited by the treatment T4 (2.58) with a net return of Rs. 189703.00 due to high cost of production in T7.ThesisItem Open Access INFLUENCE OF FERTILIZER MANAGEMENT PRACTICES ON POINT OF ZERO CHARGE (PZC) IN SOILS OF ASSAM AND ODISHA(AAU, Jorhat, 2021) Parija, Subhra; Nath Das, KulendraAn incubation study was undertaken to examine the influence of fertilizer management practices on the point of zero charge (PZC) in soils of Assam and Odisha. Six number of geo-referenced surface soil samples (0-15 cm) viz., black soil (Vertisol), laterite soil (Alfisol), red soil (Alfisol) and three alluvial soil samples belonging to Entisol, Inceptisol and Alfisol were collected from Kalahandi, Khordha and Dhenkanal districts of Odisha and Dergaon, Golaghat, ICR Farm AAU, Jorhat and Titabor, Jorhat of Assam, respectively. The soils strikingly varied in their mechanical composition, bulk density and moisture content at field capacity. The soils were mostly acidic in nature (pH 5.04 – 5.71) except black soil of Odisha which was slightly alkaline (pH 7.93). Organic carbon in Odisha soils ranged from 0.21 - 0.95% and lied between 0.47 - 0.86% in soils of Assam. All the soils were low to medium in available NPK but exhibited high content of available S. Laboratory incubation of these soils (200g) were carried out after treatment with four different fertilizer management practices viz., FYM @ 5 t ha-1 (T1), NPK @ 80:40:40 for Odisha soils and 60:20:40 for Assam soils (T2), FYM @ 5 t ha-1 + NPK @ 80:40:40 for Odisha soils and 60:20:40 for Assam soils (T3) and FYM @ 5 t ha-1 + NPK @ 80:40:40 for Odisha soils and 60:20:40 for Assam soils + Lime requirement/ Gypsum requirement (T4), in three replications. Sub samples were drawn after an interval of 15 and 30 days after treatment (DAT) and analysed. The PZSE and PZNC of the incubated samples were estimated through potentiometric titration and ion retention methods, respectively. Pearson’s correlation coefficient between PZC components and relevant soil properties was studied. The effect of the applied treatments on the PZC components and nutrient availability was evaluated using ANOVA for CRD. Results revealed that the PZSE for Odisha soils ranged from 2.18 to 4.70 and lied between 3.60 and 4.16 for the soils of Assam. The PZNC was achieved at comparatively lower pH values, ranging from 2.03 to 4.10 for Odisha soils and from 2.50 to 3.61 for Assam soils. The order of PZC for the samples was in direct correlation with their respective sesquioxide contents. Factors like clay, organic carbon, exchangeable calcium and available phosphorus imposed a significant influence on soil PZC values. The treatment T2 resulted in highest availability of the primary nutrients for all the soils under incubation while maximum availability of secondary nutrients was recorded under treatment T4. Availability of all the nutrients decreased at 30 DAT as compared to that of 15 DAT, except for Ca and Mg where the availability was more at 30 DAT. The treatment effect was insignificant on the sesquioxides content of incubated soils. Highest values of PZSE and PZNC were recorded under treatment T2 followed by T3, T4 and T1 for all the incubated soil samples of Odisha and Assam, however there was a decrease in the PZC values with increase in days of incubation. Such results confer that these soils allow more availability of anionic nutrients such as nitrate (NO3 -), phosphate (PO4 3-), sulphate (SO4 2-) immediately after fertilizer application, which slowly decreases with time favoring an increased CEC in the latter phase and thereafter enhancing the availability of cationic nutrients such as ammonium (NH4 +), potassium (K+), calcium (Ca2+), etc. In comparison to other treatments, the treatment T4 consisting of organic manures, recommended dose of chemical fertilizers along with lime/gypsum resulted as the most ideal fertilizer management practice. Besides providing optimum amount of primary nutrients and maximum amount of secondary nutrients, it regulated the PZC values favouring minimal loss of nutrients leading to enhanced crop production.ThesisItem Open Access INFLUENCE OF BIOCHAR ON SOIL PHYSICO-CHEMICAL PROPERTIES(AAU, Jorhat, 2021) Saikia, Priyambi; Patgiri, D K.The study on „Influence of biochar on soil physico-chemical properties‟ was conducted during 2019-2021 with the aim to characterize biochar obtained by pyrolysis of different organic sources, viz., ipomoea, rice straw and rice husk; and to study the influence of application of biochar on the physico-chemical properties of soils over a period of 90 days of incubation. Biochar was prepared by pyrolysis of organic sources under anaerobic condition at a temperature ranging from 350 to 400oC using the biochar kiln. pH, EC, CEC, available N, available P2O5, available K2O, water holding capacity (WHC) and bulk density of biochars ranged from 7.34 to 9.69, 0.70 to 1.13 dS m-1, 17.3 to 18.4 cmol(p+) kg-1, 0.0028 to 0.00504%, 0.0126% to 0.0258%, 0.17 to 0.34%, 101.58 to 255.36% and 0.267 to 0.465 Mg m-3 respectively. Soil samples of three different textural classes, viz., clay, clay loam and sandy were collected from the Titabor subdivision of Jorhat district for the incubation study. Soil samples were incubated for 90 days at 60% FC with each type of biochar (ipomoea, rice husk and rice straw) at 4 different levels (1, 2, 3 and 4%) in a completely randomized design. Biochar improved soil physical properties like hydraulic conductivity, soil water retention at field capacity, soil water retention at permanent wilting point, soil available water, increased sand and silt sized particles, while it decreased the clay sized particles compared to the initial value of the soils. Rice husk and rice straw biochar significantly decreased the percentage of clay sized particles (2.73%), by significantly increasing the percentage of sand and silt sized particles. All three soils showed a proportionate increment in sand and silt sized particles, while clay sized particles declined with the increase in the rate of application of biochar from 1 to 4%. When applied at a rate of 4%, rice husk biochar significantly increased the percentage of sand sized particles by its maximum value (2.25%) and rice straw biochar significantly increased the percentage of silt sized particles by its maximum value (2.42%). Application of rice husk biochar significantly improved hydraulic conductivity of the soils to the highest value (7.73 mm hr-1). Application of biochar derived from ipomoea led to significantly higher water retention at field capacity (28.10%), water retention at permanent wilting point (10.94%) and soil available water content (17.16%). Biochar showed corresponding increase in hydraulic conductivity till the application rate of 3% for clay loam and sandy clay loam soil. At the application rate of 3% rice husk biochar resulted for the highest hydraulic conductivity of the soil (9.11 mm hr-1). Soil water retention at field capacity and permanent wilting point increased proportionately with increase in the rate of application of biochar from 1% to 4% for all 32 soils except for sandy clay loam soil where soil water retention at field capacity proportionately decreased. Application of biochar at the rate of 3% and 4% significantly increased the soil available water content to the highest value (17.19%). Ipomoea at the rate of 4% led highest water retention at field capacity (29.91%) and soil available water (18.43%). Biochar significantly altered the soil pH, EC, CEC, organic carbon, available nitrogen, phosphorous and potassium content of the soils. Rice straw biochar led to significantly higher pH (5.88), EC (0.093 dS m-1) and organic carbon content (1.11%). Ipomoea biochar prompted significantly higher CEC [9.80 cmol(p+) kg-1], soil available nitrogen (251.38 kg ha-1) and available potassium content (311.41 kg ha-1). Rice husk biochar led to significantly higher available phosphorous content (72.69 kg ha-1). Soil chemical properties such as pH, EC, organic carbon, CEC, available phosphorous and potassium content was significantly increased with the increasing rate of application of biochar from 1 to 4%. Application of 4% rice straw biochar increased the soil pH, EC and soil organic carbon content to the highest level (6.39, 0.120 dS m-1 and 1.41% respectively). Ipomoea biochar at the rate of 4% led to highest CEC and soil available potassium content [11.07 cmol(p+) kg-1 and 358.59 kg ha-1 respectively]. Biochar made from rice husk at the rate of 4% increased the soil available phosphorous content to the highest level (96.06 kg ha-1). However, application of biochar till 2% resulted in increase in available nitrogen content of the soils. Further increase in application rate resulted in decrease in available nitrogen content of the soils. Ipomoea biochar at the rate of 2% increased the soil available nitrogen content to the highest level (271.71 kg ha-1).ThesisItem Open Access Impact of Weather Parameters on Winter Rice Productivity in North Bank Plains Zone of Assam(AAU, Jorhat, 2021) BURAGOHAIN, RABIJITA; Saikia, HemantaWeather parameters play a very significant role in the diversity of agriculture from region to region. The impact of weather parameters on crop health is mostly influenced by the variabilities in local or regional climate rather than the global climate patterns. Assam is well-recognized for its rich genetic diversity of rice. The climatic condition and geographical location cause greater production of rice over the past in Assam. Winter rice is the leading rice crop, accounting for a major portion of the total rice production in Assam as well as in India. In this study, an attempt has been made to find a better implementable plan for the farmers and policy makers to increase the winter rice productivity in North Bank Plains Zone (NBPZ) of Assam by analyzing over thirty years of data. NBPZ is one of the main regions, where most of its livelihood depends on agriculture. The purpose of the study was to analyze the trend of area, production and productivity of winter rice and to estimate the impact of weather parameters in winter rice productivity in NBPZ of Assam. Moreover, the analysis also revealed inter-district and intra-district variation of weather impacts on winter rice productivity. Overall thirty years of secondary data were evaluated for the study. To make a more clear vision, again data were sub-divided into three decadal periods viz. period I (1988-89 to 1997-98), period II (1998-99 to 2007-08) and period III (2008-09 to 2017-18) respectively. Different statistical tools viz. homogeneity test and change point detection of the data series over the decadal and overall thirty years were evaluated. Pettitt‟s test and Buishand‟s test were used to confirm the change point of the period. The robust non-parametric Mann-Kendall test confirmed the trend pattern of winter rice productivity in NBPZ along with Sen‟s slope estimate of the rate of change per year of area, production and productivity. Although, stepwise multiple linear regression was performed to estimate the effects of climate change on winter rice productivity. The four weather parameters viz. maximum temperature, minimum temperature, rainfall and rainy days were considered for weather impact assessment. These parameters possess the most significant fluctuations in the NBPZ of Assam. Analyzing over thirty years of the dataset for the aggregate of NBPZ also resulted that the productivity of winter rice being highly influenced by maximum temperature and minimum temperature. Although, Period III of Sonitpur and Lakhimpur district, the number of rainy days were found significant for winter rice productivity. The analysis over the past decades of NBPZ was to provide essential information to the agricultural planner and policymakers responsible for designing efficient agricultural policies and for making significant decisions concerning resources allocation for the development of the agricultural sector in NBPZ as well as for Assam. The study revealed that the NBPZ is not limited to studying climate-resilient productivity of winter rice only, there is a great need for implementation of effective measures as crop production and productivity has a greater influence on the socio-economic needs of the people. Keywords: Winter rice, NBPZ, weather parameters, MK-test, Stepwise multiple linear regression. .ThesisItem Open Access Impact of modified microclimate on the performance of green gram under different planting systems in Upper Brahmaputra Valley Zone of Assam(AAU, Jorhat, 2021) Pathak, Karabi; Neog, PrasantaA field experiment was conducted during the summer, 2021 in the Instructional-Cum-Research (ICR) Farm of AAU, Jorhat to study the Impact of modified microclimate on the performance of green gram under different planting systems in UBVZ Assam. The variety SGC-16 was grown in a split-plot design with 3 dates of sowing (D1-20th February, D2-6th March, and D3-20th March) in main plots and three planting systems (P1 – ridge and furrow, P2 – raised bed with two rows in bed and P3 –flat bed ) in sub-plots, with three replications following recommended agronomic practices. Microclimatic parameters such as soil temperature (10 cm depth) and soil moisture content at two depths (0 - 15 cm and 15 - 30 cm) were recorded at regular intervals. The different components of photo-synthetically active radiation (PAR), viz., incident (IPAR), and transmitted (TPAR) were recorded at 7 days intervals using line quantum sensor (Model LQM-70-10) at local noon time (11:30 AM). Crop growth parameters viz., plant height, leaf area index and dry matter accumulation, phenological observations and yield attributing characters, and seed yield were recorded. Agro-climatic indices viz., growing degree day (GDD), heliothermal unit (HTU), phenothermal index (PTI), and heat use efficiency (HUE) for biomass and seed yield were computed following standard procedures. The daily maximum temperature never exceeded 37.6°C, but the daily minimum temperature went below 20°C (up to 12.4°), which was detrimental to the crop. The average soil moisture content in the upper 30 cm soil profile was the highest in the D3 (80.39 mm), followed by D2 (75 mm) and D1 (66.4 mm). As compared to P3, the decrease in weekly evening soil temperatures under P1 and P2 was up to 2.1 and 1.4°C, respectively. Incident PAR (IPAR) during the crop growth season varied from 712 to 1721 μ mol s-1 m-2. In all dates of sowing and planting systems, the lowest transmitted PAR was recorded in the case of D3 date of sowing and in P1, when the crop was with full canopy coverage. The crop took 4 to 11 days, 28 to 35 days, 34 to 43 days, 39 to 50 days, and 62 to 75 days to attain the different phenological events, such as emergence, bud formation, flowering, pod initiation, and physiological maturity, respectively under different sowing dates and planting systems. Irrespective of sowing dates mean maximum leaf area index was recorded in P1 (2.06), followed by P2 (1.91) and P3 (1.77). The biomass production at maturity was highest in D3 (15.6 g plant-1), which decreased in earlier dates of sowing, while it was highest under P1 (14.6 g plant-1), followed by P2 (13.4 g plant-1) and P3 (11.6 g plant-1), irrespective of sowing dates. The seed yield of green gram cultivar SGC-16 sown under different sowing dates and planting systems ranged from 286.3 to 681 kg ha-1 with an overall mean of 509.8 kg ha-1. Irrespective of sowing dates, the highest GDD accumulation in the entire growth period was recorded under the P1 (1010°C day) system, followed by P2 (973°C day) and P3 (930°C day). The accumulation pattern of PTU by the crops under different treatments was similar to that of GDD. HUE for total biomass production and seed yield ranged from 2.61 to 4.01 kg ha-1°C-1 and 0.38 to 0.65 kg ha-1°C-1, respectively. Regression studies showed that there were linear significant relationships between total biomass, seed yield, and max LAI with iPAR .Correlation studies between seed yield, and thermal indices confirmed the existence of a significant and positive correlation between them.ThesisItem Open Access IMPACT OF CERTAIN NEWER INSECTICIDES ON SOIL FAUNAL DIVERSITY IN FRENCH BEAN (Phaseolus vulgaris L.)(AAU, Jorhat, 2021) Nath, Gourismita; Bhagawati, SudhansuLaboratory and field experiments were carried out in the Department of Entomology; Department of Plant Pathology and Horticulture Experimental Farm of Assam Agricultural University, Jorhat during 2020-21 to study the impact of certain newer insecticides on soil faunal diversity in French bean. Six newer insecticides viz., clothianidin 50 WDG, fipronil 0.3 G, thiamethoxam 25 WG, imidacloprid 70 WG, chlorantraniliprole 0.4 GR and fipronil 40%+ imidacloprid 40% WG were selected for conducting the experiment. Sampling for soil macro and microarthropods as well as soil microbial population were done at pre-treatment, 15, 30, 45 60 and 75 days after treatment (DAT). The soil macroarthropods were sampled using pitfall traps whereas the microarthropods were extracted through Tullgren Funnel. Assessment of soil microbial population was done by following the standard pour plate method. Experimental results revealed the hymenopterans as the most dominant group (54.74%) among the different soil macroarthropods observed prior to the application of insecticides followed by Coleoptera (13.68%) and Araneae (11.57%). Among the soil microarthropods, the abundance of Collembola and Oribatida were recorded to be 64.72 and 35.28 per cent, respectively in the pre-treated plots. The number of soil macroarthropods was ranged between 89.00 to 95.33/plot prior to the application of insecticides which showed statistical parity with each other. At 15 DAT, the abundance of soil macroarthropods in all the treated plots were reduced significantly (47.33-52.67 numbers) compared to the untreated control (89.33 numbers). However, maximum number of soil macroarthropods/ plot was recorded in chlorantraniliprole 0.4 GR treated plots (52.67) followed by clothianidin 50 WDG (50.33) and thiamethoxam 25 WG (49.67) treated plots. Perusal of data in respect of 30, 45, 60 and 75 days after treatment also showed a significant decrease in the numbers of soil macroarthropods as compared to the control, however, a gradual increase in the total number of soil macroarthropods was observed in each treated plots from 30 DAT onwards. Soil microarthropods obtained in different plots prior to the application of insecticides was ranged between 458.33 to 555.56 numbers/sq. m. All the insecticidal treatments did not exhibit any significant (p=0.05) impact on soil microarthropod population during the experimental period. 7 Assessment of soil microbial population revealed a significant decrease in the total bacterial (58.67-62.67) and fungal (48.00-51.67) population (cfu×104/g of soil) in all the treated plots at 15 DAT as compared to the control (98.67 bacterial and 91.67 fungal cfu×104/g of soil, respectively). However, maximum number of both the bacterial and fungal colonies (cfu×104/g of soil) were recorded in chlorantraniliprole 0.4 GR treated plots (62.67 and 51.67, respectively) followed by clothianidin 50 WDG (62.00 and 51.00, respectively) and thiamethoxam 25 WG (61.33 and 50.33, respectively) treated plots. A similar trend of results were also observed while the total population of bacterial and fungal colonies were assessed at 30, 45, 60 and 75 DAT. However, a gradual increase in the total bacterial and fungal population was observed in each treated plots from 30 DAT onwards showing the ability to overcome the toxic effect of insecticides by the microbes in the subsequent period of the experiment.ThesisItem Open Access IDENTIFICATION, CHARACTERIZATION AND MANAGEMENT OF PUMPKIN MOSAIC DISEASE(AAU, Jorhat, 2021) Gogoi, Kulumanali; Mishra, RanimaThe present investigation was conducted for identification, characterization and management of pumpkin mosaic disease in Assam. A roving survey was conducted during 2019-2021 in Jorhat, Golaghat, Karbi Anglong, Biswanath Chariali and Charaideo to determine the disease incidence through symptomatology, vector population count and detection of the viruses associated with mosaic disease of pumpkin through serodiagnostic (DAS-ELISA) and molecular assay (PCR and RT-PCR). Symptomatology revealed various degrees of mosaic, mottling, vein clearing, vein banding, chlorosis, leaf distortion, small, crinkled, deformed leaves and malformed fruits with mosaic and chlorotic spots resulting in reduced yield and production. Serological detection through DAS-ELISA confirmed the association of Cucumber mosaic virus (CMV) in CMV suspected pumpkin samples. The DAS-ELISA assay revealed disease incidence of 52.38 per cent in Golaghat district and 35.71 per cent in Jorhat district. Two different types of aphid vectors viz., Aphis gossypii and Myzus persicae were observed in all the surveyed locations. Total genomic RNA extracted from symptomatic and asymptomatic pumpkin plants were subjected to RT-PCR assays using CMV, zucchini yellow mosaic virus (ZYMV) and watermelon mosaic virus (WMV) specific primers and Deng universal primer for detection of begomovirus viz., pumpkin yellow vein mosaic virus (PYVMV). RT-PCR assay revealed the presence of CMV in the samples which yielded the desired amplicon size of 593 bp. No amplification was obtained from the samples for ZYMV and WMV. PCR product of CMV infected sample from Jorhat district viz., CMV-CP Jorhat isolate was sequenced and compared with the known CMV isolates worldwide using nucleotide BLAST programme at National Centre for Bio Informatics (NCBI) and Mega X software. The sequence similarity of CMV-CP Jorhat isolate ranged from 93.11 per cent to 99.16 per cent with worldwide CMV isolates. A field experiment was conducted for management of pumpkin mosaic disease through integrated approach. It was evident from the field experiment that there was low disease incidence with low vector population as well as high yield in the treatments of hot water seed treatment at 50⁰C for 10 minutes and spraying of neem formulation @3ml/lit at 15, 30, 45 and 60 days after transplanting (T1) followed by hot water seed treatment at 50⁰C for 10 minutes and spraying of Imidacloprid @2ml/lit at 15, 30, 45 and 60 days after transplanting (T6) than the other treatments with the highest yield (80.00 q/ha) recorded for the treatment T1 with highest per cent reduction of disease over control (53.22 per cent).
