Loading...
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.
Browse
3 results
Search Results
ThesisItem Open Access ASSESSMENT OF ZINC USE EFFICIENCY IN MAIZE-MAIZE CROPPING SEQUENCE(2022) Borah, Sanjib Ranjan; Basumatary, AnjaliA field experiment was conducted at Krishi Vigyan Kendra, Jorhat farm, Kaliapani, Teok, Assam Agricultural University during 2018-19 and 2019-20 to study the influence of zinc fertilization on zinc fractions in soil, its relationship with important soil properties, yield, nutrient uptake and zinc use efficiency in maize-maize cropping sequence. The experiment was laid down in a randomized block design (RBD) with twelve treatments consisted of zinc applied as soil with or without foliar application through zinc sulphate and zinc oxide nano particle (ZnO NPs). Distribution of different zinc fractions in soil were assessed after harvest of each crop in the sequence. Perusal of experimental findings revealed that zinc fertilization had a significant influence on different zinc fractions in soil during both the years under investigation. The study revealed that among the zinc treatments, soil application of Zn @ 3.75 kg ha-1 in combination with foliar application of 500 ppm ZnO NPs exhibited the highest water soluble plus exchangeable-Zn content of 1.10 mg kg-1 in soil. The highest concentration of complexed-Zn (2.95 mg kg-1), amorphous sesquioxide-bound- Zn (4.11 mg kg-1), crystalline sesquioxide-bound-Zn (3.76 mg kg-1), residual-Zn (125.65 mg kg-1) and total-Zn (137.33 mg kg-1) were recorded in the treatment receiving soil application of Zn @ 7.5 kg ha-1. Among the zinc fractions studied, the concentration and percent contribution of water soluble plus exchangeable-Zn to total-Zn was the lowest while residual-Zn fraction contributed the highest to the total soil zinc pool. Path coefficient analysis showed that the water soluble plus exchangeable-Zn had the highest contribution towards the DTPA extractable-Zn in soil. The distribution of different zinc fractions at post-harvest soil was found in the following order: water soluble plus exchangeable-Zn < complexed-Zn < crystalline sesquioxide bound-Zn < amorphous sesquioxide bound-Zn < residual-Zn. All the fractions of zinc were found to be significantly and positively correlation with each other indicating existence of dynamic equilibrium of zinc in soil. Zinc fertilization exerted a significant influence on available nutrient status of soil. The highest available nitrogen content of 182.50 kg ha-1 was found in the treatment receiving soil application of Zn @ 3.75 kg ha-1 in combination with foliar application of 500 ppm ZnO NPs. The available phosphorus content in soil was decreased with zinc fertilization and thus, soil application of Zn @ 7.5 kg ha-1 recorded the lowest available phosphorus content of 19.45 kg ha-1, while the highest phosphorus content of 23.74 kg ha-1 was recorded in the control. However, no significant influence of zinc fertilization on available potassium, exchangeable calcium and exchangeable magnesium content in the post-harvest soils were observed. The highest available sulphur content of 25.50 kg ha-1 was registered in the treatment receiving soil application of Zn @ 7.5 kg ha-1. In respect of content of available micronutrients in soil, the DTPA extractable Fe, Cu and Mn content in soil were decreased with Zn fertilization and the highest content of DTPA extractable Fe (37.38 mg kg-1), Cu (0.42 mg kg-1) and Mn (9.26 mg kg-1) in soil was recorded in the control treatment, whereas, the lowest content was found in the treatment receiving Zn @ 7.5 kg ha-1. Application of 500 ppm ZnO NPs as foliar with soil application of Zn @ 3.75 kg ha-1 recorded significantly the highest DTPA extractable Zn content of 1.33 mg kg-1 in the post harvest soil. The study also revealed that zinc fertilization significantly influenced the grain and stover yield of maize. Perusal of pooled data indicated that among the zinc treatments, combined application of 500 ppm ZnO NPs as foliar with soil application of Zn @ 1.25 kg ha-1 registered the highest grain yield (65.04 q ha-1), stover yield (80.39 q ha-1) and harvest index (46.95%) in maize- maize sequence. Zinc fertilization exhibited a significant influence on uptake of major as well as micronutrients by maize. The highest uptake of nitrogen, potassium, calcium and magnesium by maize crops were recorded in the treatment receiving soil application of Zn @ 1.25 kg ha-1 in combination with 500 ppm ZnO NPs as foliar. The highest uptake of phosphorus by grain (14.81 kg ha-1) and stover (18.22 kg ha-1) was recorded in the treatment receiving 500 ppm ZnO NPs as foliar whereas, the highest sulphur uptake by grain (9.95 kg ha-1) and stover (11.72 kg ha-1) was found in the treatment receiving combined application of 500 ppm ZnO NPs as foliar with soil application of Zn @ 3.75 kg ha-1. Among the micronutrients, the highest uptake of Fe (214.56 g ha-1), Cu (31.99 g ha-1), Mn (56.33 g ha-1) and Zn (156.36 g ha-1) by maize grain was found in the treatment receiving combined application of 500 ppm ZnO NPs as foliar with soil application of Zn @ 1.25 kg ha-1. The highest uptake of Fe (846.24 g ha-1), Cu (45.99 g ha-1), Mn (248.57 g ha-1) and Zn (279.58 g ha-1) by maize stover was also found in the same treatment. Analysis of pooled data indicated that method of zinc fertilization had significant influence on zinc use efficiency by maize. The highest agronomic efficiency (2382.51 kg kg-1), apparent recovery efficiency (36.88%), zinc utilization efficiency (4067.44 kg kg-1) and partial factor productivity (16913.19 kg kg-1) was recorded in the treatment receiving foliar application of 500 ppm ZnO NPs. The highest physiological efficiency (12816.13 kg kg-1), agro physiological efficiency (7567.77 kg kg-1) was recorded in the treatment receiving combined application of 500 ppm ZnO NPs as foliar with soil application of Zn @ 1.25 kg ha-1. Cost benefit analysis revealed that among different treatment combinations, the highest gross return (Rs. 1,17,072.00), net return (Rs. 82,773.00) and highest B-C ratio (2.41) was registered in the treatment receiving 500 ppm ZnO NPs as foliar in combination with soil application of Zn @ 1.25 kg ha-1. Considering improvement of crop yield and economic return, combined application of 500 ppm ZnO NPs as foliar with soil application of Zn @ 1.25 kg ha-1 was found to be superior over other treatmentsThesisItem Open Access SPATIAL ANALYSIS OF HEAVY METALS IN SOIL, PLANT AND GROUNDWATER IN NAGAON DISTRICT OF ASSAM USING GIS TECHNIQUE(2022) Hazarika, Prarthana Priyom; Medhi, Dr. B. K.Geospatial as well as geostatistical approaches using GIS tool to assess and characterize heavy metals namely Cd, Cr, Cu, Ni, Zn, Pb, Fe, As and Mn in soil, crop, and groundwater, their degree of pollution level, and phytoextraction behaviours of key metals were carried-out in Nagaon district of Assam during 2018 to 2021. To appraise the potential heavy metal sites, a random systematic method was used for sampling strategy by dividing the study area into a grid of 5 km× 5 km and collecting 160 composite soil samples from 0-15 cm depth for the total content of heavy metals using Atomic Absorption Spectrophotometer (Model: iCE 3500, Thermofisher). Geospatial analyses from different thematic maps of heavy metals revealed significant vulnerable points of elevated concentrations of Cd (> 0.31 mg/kg ), Pb (> 24.45 mg/kg ) and Ni (> 0.05 mg/kg ) in soils and Cd (>0.01 mg/L), Cr (>0.05 mg/L), Cu (>1.3 mg/L ), Fe (> 0.3 mg/L ), As (> 20 mg/L ) and Mn (> 0.1 mg/L ) in groundwater which is presumed to be due to anthropogenic factors. Geospatial interpolation pedagogies like Inverse Distance Weighted, Global Polynomial Index, Local Polynomial Index, Kriging, Kernel Smoothing and Diffusion Kernel were tested to estimate the metal concentrations at unsampled locations for assessment of their performance by comparing the Root Mean Square Error (RMSE) for cross-validation and all models provided more or less high prediction accuracy to mean value of the metals. Specific to the Kriging model, it was found to be best fitted with the lowest RMSE in all the metals except Mn and Ni in the soil where IDW and local Polynomial index was found to give the lowest RMSE. Other geospatial models that interpreted better groundwater heavy metals content with lowest RMSE were Inverse Distance Weighted Interpolation for Ni and Pb, Local Polynomial Index for Mn, Global Polynomial Index for Fe. The three-dimensional trend over the distribution of metals throughout the district best fitted the secondorder polynomial for Cd, Cu, Ni, Zn, Pb, Fe, As, and Mn in soils while both first and second-order polynomials according to XZ and YZ dimensions fitted well for Cd, Ni, Mn, Pb, Ni, and Cu in groundwater. Significant numbers of pairs of heavy metals to a certain extent were found to be spatially autocorrelated and all the pairs away from X-axis towards the extreme right corner and far above the axis reflected less influence of local characteristics of the heavy metal. Spatial autocorrelations were detected for 9 heavy metals and the autocorrelation distances were; Cd 60; Cr 60; Cu 60; Ni 55; Zn 57; Cu 55; Pb 65; Fe 68; As 62 and Mn 65 km for soil and Cd 60 Cr 57; Ni 65; Zn 57; Pb 60; Fe 65; As 57and Mn 60 km for groundwater. Co-variance cloud with search direction from North to South revealed the existence of spatial autocorrelation revealing a wider spatial shift of correlation towards the southern direction. The Pollution Indices (Single Pollution Index, Geo-accumulation Index, Ecological Risk Factor) showed the highest threat to the soil from Pb, Cd, and Ni respectively. Overall Multi Pollution Indices (Pollution Load Index, Average Single Pollution Index, Enrichment Factor, and Nemerow Pollution Index) encompassing all the metals showed that although there was considerable pollution in the soil, the soil was under the critical limit but towards the higher side. The Bio-concentration, Bio-accumulation, and Translocation Factor as was revealed from the pot culture experiment taking toria (variety TS-67) as test crop was found below 1 for all the graded levels of Pb envisaging the crop inefficient to hyperaccumulate, phyto-stabilize and phyto-extract Pb from the soil. A higher value of Bio-concentration Factor (>1) for Cd and Ni, revealed the crop efficiently hyper-accumulates Cd and Ni. BAF (>1) for Cd levels at 0.5 ppm, 1.0 ppm, and 1.5 ppm and Ni levels baring 60 ppm indicated the crop to be able to phytostabilises both Cd and Ni at lower concentrations. The Translocation Factor (< 1) for Cd and Ni was indicative of the inefficiency of toria to phytoextract Cd and Ni in its aerial parts. The study helped to find out the hotspots for certain heavy metals in the district which would certainly help in further decision making and take viable removal measures as well as suitable cropping systems. GIS maps validated through geostatistical approaches help in contributing contamination characteristics, degree of pollution of heavy metals in soils as well as groundwater based on which desired phytoremediation planning may be adopted.ThesisItem Open Access AGRO-PEDOLOGICAL ASSESSMENT OF THE TRADITIONAL AGARWOOD (Aquilaria malaccensis) GROWING AREAS OF UPPER BRAHMAPUTRA VALLEY ZONE, ASSAM(2022) Bordoloi, Anshuman; Dutta, SamironThe present investigation was carried out in some traditional Agarwood growing areas of the Upper Brahmaputra valley zone of Assam for pedogenic characterization of the soils and to evaluate the soil fertility status and microbial properties of soils around the Agarwood trees of high and low market values. The plant nutrient content and biochemical properties of the leaf of both types of trees were also determined and their relation with soil properties was assessed. An attempt was also made to evaluate the influence of different soil and plant properties on the quality of Agar trees of the area. To accomplish the objectives, ten locations were selected from three districts of the Zone. The highest number of locations (six) were selected in Golaghat district (Dhekial, Kakodunga, Naharani, Haanhpani, Podumoni, and Halowagaon) because of its largest area under Agarwood production. Out of the remaining four locations, two were selected in Jorhat (Alengi and Pirakota) and the other two were taken from Sivasagar district (Namti and Mathurapur). A soil profile was exposed in each location to characterize and classify the soils. Besides 120 numbers of composite surface (0-25 cm) and subsurface (25-50 cm) soil samples were collected from near the trunk of good and poor quality agar trees of all the locations. In addition to soil samples, equal numbers of plant samples were also collected from these trees for the present study. The soils were dark yellowish-brown to brownish-yellow in colour and loam to clayey in texture. The sand, silt, and clay content of the soil profiles varied from 28.1- 54.5%, 19.6 -37.3%, and clay 22.7-42.8% respectively. Soil structure was mostly weak to medium sub-angular blocky. The bulk and particle density of the soils ranged from 1.19 -1.59 Mg m-3 and 2.48-2.61 Mg m-3 respectively. The average water holding capacity of the soils was found to be greater than 30%. The soils were very strongly acidic to slightly acidic with a pH range from 4.79 to 6.60 and found to increase with the depth of soils. The organic matter content of the soils was invariably high (>0.75%) in the surface horizons which decreased regularly with the depth of soils. The free Fe and Al oxides of the soils varied from 1.43-2.93% and 0.37-0.85% respectively. Among the exchangeable cations Ca was the most dominant cation followed by Mg, Na, and K. The CEC of the soils was quite low with a range from 7.8 to 10.5 cmol(p+)kg-1. The exchange acidity, Total acidity, and extractable Al of the soils varied from 1.38 -3.37, 2.22-4.28, and 2.04- 3.35 cmol(p+)kg-1respectively. The exchangeable Al contributed more than 80% of the exchange acidity of the soils. The average Al saturation was found to be more than 30% in all the soils. The morphological and physicochemical properties of soils indicated the development of a cambic horizon in the studied soils. Based on these properties, all the soils were classified as Typic Dystrudepts at the subgroup level except soils of Namti and Mathurapur of Sibasagar district which were classified as Ruptic Alfic Dystrudepts due to higher base saturation in lowermost horizons. The properties determined in composite soil samples showed significant variation among the different locations. The pH and organic carbon of the surface and subsurface soils ranged from 4.97 -5.80 and 1.08-1.37% respectively. The available N and P of the soils were medium on the surface while low to medium in subsurface soils. The status of available K was low to medium. The Ca and Mg content of the surface soils varied from 2.05-2.38 and 1.03-1.40 cmol(p+)kg-1 and in subsurface they ranged from 1.66-3.04 and 0.71-1.10 cmol(p+)kg-1 respectively. The content of S, Fe, Mn, Zn, and Cu of all the soils irrespective of depth was found to be sufficient barring a few irregularities. The B content however was deficient in all the soils (< 0.50 mg kg-1). The MBC and MPS of the surface soils varied from 455.44-827.31 and 6.09-7.43 and 327.36-668.37 and 5.54-7.69 in subsurface soils respectively. Most of these parameters showed significant variation between the soils under good and poor quality Agarwood trees except N, Ca, Mg, S, Fe, and Mn of soils. The nutrient content of leaf, bark, and wood showed significant variation among different locations. The range of nutrients for leaf N, P, K, Ca, Mg and S were 2.12 – 2.475 %, 0.176- 0.187 %, 0.558-0.629 %, 0.367- 0.475 %, 0.275-0.282 % and 0.034- 0.052 % respectively. The N, P, K, Ca, Mg and S of bark ranged from 1.152–1.477 %, 0.060-0081 %, 0.396-0.491 %, 0.329-0.446 %, 0.127-0.180 % and 0.019-0.028 % respectively. Similarly in wood these nutrients varied from 0.315- 0.516%, 0.062 - 0.081 %, 0.147 to 0.208 %, 0.231- 0.365 %, 0.120 – 0.226 % and 0.014-0.020% respectively. It was observed that the difference in concentration of the nutrients in soil under trees with good and poor health differ significantly and was found to be higher in soils under the tree with poor health. A similar observation was also made in the biochemical properties of the leaf. A significant relationship was observed between the plant nutrient concentration and nutrient content of soils. The biochemical properties also showed an identical relationship barring a few exceptions. An attempt was made to evaluate the influence of different soil properties, plant nutrient concentration, and biochemical properties on the quality of Agarwood trees through PCA. The PCA identified MBC, microbial population, the content of Zn, Cu, available P, available K, and organic carbon as the major soil factor that might have played crucial role in determining the quality of Agarwood trees. In addition to these soil factors, the nutrient concentration of bark and wood, concentration of secondary nutrients in leaf, and biochemical properties like total carbohydrate, chlorophyll-A, total chlorophyll, and residual sugar might be the other important plant factors determining the resinwood quality of Agarwood trees. Interestingly the content of all these properties identified through PCA was higher in the soils collected from near the trunk of trees with poor health and the plant samples collected from such plants. The pH and content of Zn in surface soils, MBC, and microbial populations were an exception.
