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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Soil quality index and nutrient balance in rice-rice cropping system under long-term fertilizer experiment(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellanikkara, 2021) Drishya, D S; KAU; Thulasi, VLong-term experiments provide the best possible platform for studying the changes in soil properties and processes, identifying emerging trends in nutrient imbalances and deficiencies and help to formulate future strategies for maintaining soil health and quality. The present study entitled “Soil quality index and nutrient balance in rice-rice cropping system under Long Term Fertilizer Experiment” was undertaken at RARS, Pattambi and College of Agriculture, Vellanikkara. The objectives were set out to estimate soil quality index and NPK balance in rice-rice cropping system as affected by nutrient management practices under Long Term Fertilizer Experiment. The Long Term Fertilizer Experiment (LTFE) in rice-rice cropping system maintained (since 1997) at RARS Pattambi has been laid out in RBD consists of 12 treatments viz.,T1 : 50 per cent NPK, T2 : 100 per cent NPK, T3 : 150 per cent NPK, T4 : 100 per cent NPK + 600 kg ha -1 CaCO3 , T5 : 100 per cent NPK, T6 : 100 per cent NP, T7 : 100 per cent N, T8 : 100 per cent NPK + Farm Yard Manure (FYM) @ 5 t ha -1 , T9 : 50 per cent NPK + FYM @ 5 t ha -1 , T10 : 100 per cent NPK + in situ growing of Sesbania aculeata, T11 : 50 per cent NPK + in situ growing of Sesbania aculeata and T12 : Absolute control (No fertilizer or manures). The soil samples from 0-15 cm depth were collected from the different treatments of LTFE after the harvest of Virippu crop, 2020 and were analysed for various physical, chemical and biological properties. Principal Component Analysis (PCA) was performed to arrive at the Minimum Data Set (MDS) and Soil Quality Index (SQI) was formulated for different nutrient management practices. Integrated nutrient management with FYM and in situ green manuring with daincha recorded higher grain and straw yields of rice. The increase in fertilizer load into the soil resulted in increase in yields while the omission of primary nutrients resulted as decline in yields. Integrated Nutrient Management practice (INM) of application of FYM along with 100 percent NPK had lower bulk density (1.17 Mg m-3 ) and higher water holding capacity (43.65 %), higher levels of available nutrients and enzyme activities in the soil. However, dehydrogenase activity did not follow the same trend as that of microbial biomass carbon in treatments wherein fertilizers alone were applied indicating the chances of shift in the microbial populations as a result of the long term application of nutrient management practices. Principal Component Analysis (PCA) was performed for 28 soil attributes to develop the MDS and SQI was formulated using non linear scoring method. The MDS included bulk density, porosity, soil pH, permanganate oxidizable carbon, available N, total N, available sulphur, microbial biomass carbon, acid phosphatase and aryl sulfatase activities. The SQI ranged from 1.82 to 3.01. The SQI declined in the order of: T8> T10 >T9> T11> T4> T3> T2= T1> T5> T6 >T7> T12. The highest SQI was observed in T8 where 100 per cent NPK and FYM were applied. When the dosage of fertilizers was increased from 50% to 100% NPK on integration with FYM, the SQI increased. The soil quality index of the INM treatments (55.50 to 62.11%) and lime incorporation (52.98%) were categorized under medium category as per the computed Relative SQI (RSQI) values. The virippu crop (2020) under LTFE maintained at RARS Pattambi was monitored and various inputs and outputs regarding primary nutrients were assessed for balance predictions using NUTMON toolbox. The NUTMON toolbox includes five inflows, viz., mineral fertilizers (IN1), manure (IN2), atmospheric deposition (IN3), biological N fixation (IN4), and sedimentation (IN5), and five outflows, viz., harvested product (OUT1), crop residues (OUT2), leaching (OUT3), gaseous losses (OUT4), and erosion (OUT5). Nutrient flows like fertilizers, manures, crop residues and harvested outputs were monitored and measured during the experiment. Other flows like nitrogen fixation, leaching, and erosion were estimated by means of regression models from the data related to climate and crop parameters. Available NPK content of soils, rice grain, straw, stubbles, weeds and all inputs were analysed and stored in background database. The data were fed into the data processing module of the NUTMON toolbox to arrive at the partial and total balance of N, P and K in the experimental soil. The total balance of N, P and K were found to decline in order of: T3>T7>T8>T6>T5>T2>T4>T10>T9>T1>T11>T12 for N, T3>T8>T6>T10>T2>T5>T4>T9>T1>T11>T12>T7 for P and T3>T2>T5>T8>T9>T10>T4>T11>T1>T12>T7>T6 for K Summarizing the results, integrated nutrient management with FYM and in situ green manuring with daincha recorded higher yield and available nutrients in the soil. The incorporation inorganic fertilizers with FYM, daincha and lime maintain the soil quality index in the long run while, SQI was poor in control, imbalanced nutrition as well as in treatments where only fertilizers were incorporated. The balance sheet of P establishes the need for maintenance dose of P fertilizers in rice-rice cropping system. The negative balance of N and K indicate the need for supplementing the nitrogen pool and the possibility of mining of K on long term intensive cropping, respectively. Further study should be focused on monitoring the soil quality index at regular intervals and analyzing the effect of nutrient management practices on microbial diversity in rhizosphere and phyllosphere.ThesisItem Open Access Evaluation of water hyacinth co- composts for nutrient retention in lateritic soil(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellanikkara, 2021) Anisha, V A; KAU; Durga Devi, K MWater hyacinth is a serious menace in low land ecosystems and it’s spread has threatened water quality and aquatic life. Various biological, chemical and physical methods that have been employed to control the weed has yielded minimal results. Hence management through utilization is a viable strategy. It can be effectively utilized in many ways to support crop production. Co-composting has been proved as a promising technique for safe and quick disposal of the weed by utilizing the co-substrates viz., poultry manure, sawdust, biochar, glyricidia, paddy straw, dried leaves and cattle manure. As the weed accumulates N, P, K and other essential nutrients, compost made from water hyacinth can be utilized for improving soil fertility and crop production. Hence, the present investigation entitled “Evaluation of water hyacinth co-composts for nutrient retention in lateritic soil” was under taken in the Department of Soil Science and Agricultural Chemistry at College of Agriculture, Vellanikkara during 2020-2021. The objectives were; (i) To find out the suitable combination of water hyacinth and co-substrates for enhancing the quality of water hyacinth composts (ii) To assess the nutrient retention capacity of different co-composts in lateritic soil. Different co-substrates were collected from nearby areas and water hyacinth was collected from Kole lands of Thrissur. Water hyacinth and co-substrates were characterized prior to composting. Water hyacinth co-composts (vermi compost) were prepared using the aforesaid substrates in concrete tanks. The physical and chemical properties of the composting mixtures were recorded at 40 days interval starting from 20 days of composting until 100 days. The yield of water hyacinth co-composts was estimated and the various co-composts were characterized for their physical and chemical properties. Incubation study was conducted to evaluate the nutrient retention capacity of different water hyacinth co-composts in lateritic soil during December 2020 with eight treatments and three replications (soil+ 7 co-composts and soil alone as absolute control). The lateritic soil for study was collected from Instructional Farm, Vellanikkara and analysed for chemical properties. Compost amended soils were incubated for a period of 28 days and nutrient retention capacity (N, P, K, Ca, Mg, S, B, Zn) was estimated at 4 different time periods after incubation (7, 14, 21, 28 days). Data on characterization of co-substrates revealed that substrates vary in their chemical properties and nutrient content. Among the co-substrates, poultry manure possessed many favourable characteristics. Changes in physical and chemical properties of composting mixtures at different intervals indicated the progress of composting process and stage of compost maturity. All the co-substrates gave reasonably good yield of water hyacinth co-composts. A notable increase in compost yield to an extent of 159.7 per cent was realized in the biochar treatment. Addition of co-substrates improved the bulk density and porosity of water hyacinth co-composts. Application of co-substrates improved the pH of final compost. Highest increase was noticed in the treatment with paddy straw. Addition of paddy straw had significant adverse effect on the electrical conductivity of final co-compost (170.6 % increase in EC over water hyacinth sole treatment) and all the other treatments showed EC below maximum permissible limit for plant growth. The total carbon content of all the co-composts was higher than water hyacinth sole compost. Nitrogen content of the co-compost was improved to a greater extent by the application of paddy straw and poultry manure. Co-composts with sawdust, biochar and dried leaves had significantly lower quantity of nitrogen compared to water hyacinth sole compost. Glyricidia and poultry manure were highly effective in improving total phosphorus content of the co-compost. Total potassium content of water hyacinth compost was significantly improved with the addition of co-substrates like paddy straw and biochar, the extent of increase being 192 and 170 per cent, respectively. Carbon to nitrogen ratio of water hyacinth co-compost was significantly lowered by using poultry manure as a co-substrate. Addition of poultry manure improved all the three secondary nutrients viz., Ca, Mg and sulphur to a higher magnitude. No favourable effect was noticed on the boron content of co-compost by the addition of different co-substrates. However, Fe and Mn levels of final co-composts were considerably lower than the water hyacinth sole compost. This could be considered as a favourable effect of co-composting of water hyacinth with different substrates. Zinc content of the co-compost was significantly improved by the inclusion of co-substrate particularly with the use of poultry manure and dried leaves. Copper content of the co-compost was significantly higher with the addition of poultry manure as co-substate. The addition of co-compost to lateritic soil, improved retention of nutrients particularly nitrogen. The only exception was co-compost with paddy straw (0.9 per cent decrease in the nitrogen retention capacity). Irrespective of the treatments, cocompost retained all the phosphorus and boron present in the co-compost amended soil. The soil’s potassium, magnesium, sulphur and zinc retention capacity could be improved when amended with water hyacinth co-compost. In general, soil with biochar co-compost showed significantly high retention capacity with respect to plant nutrients particularly nitrogen. Further study should be focused on field experiments to test the agronomic efficiency of different water hyacinth co-composts, testing suitability of various crop residues and organic wastes as co-substrates and to derive suitable substrate combinations and ratios to eliminate the adverse effects of co-substrate on compost quality.ThesisItem Open Access Assessment of soil quality in the post - flood scenario of AEU 9 in Pathanamthitta district of Kerala and generation of GIS maps(Department of Soil Science and Agricultural chemistry, College of Agriculture, Vellayani, 2021) Shafna, S H; KAU; Gladis, RA study entitled “Assessment of soil quality in the post-flood scenario of AEU 9 in Pathanamthitta district of Kerala and generation of GIS maps” was carried out during 2018-20 with the objective to evaluate the soil quality in the flood affected areas of AEU 9 of Pathanamthitta district, to work out the soil quality index and to generate maps of various soil attributes and quality indices using GIS techniques. Survey conducted to identify the flood affected areas in AEU 9 of Pathanamthitta district revealed that the flood affected panchayats includes Kaviyur, Thumbamon, Kulanada, Thottapuzhassery, Kallupara, Mezhuvely, Panthalam, Kozhanchery, Aranmula, and Mallapally. All these panchayats were severely affected by flood havoc and submergence that occurred in Manimala, Pamba and Achankovil rivers during August 2018. A total of seventy five geo referenced surface soil samples were collected from the flood affected panchayats and analyzed for various physical, chemical and biological attributes. Minimum data set of soil indicators for computing soil quality was selected using principal component analysis. The selected parameters were sand content, bulk density, available B, available S, available K, available Mn and organic carbon. Scores and weights were assigned to each selected indicator, and computed the soil quality index. GIS techniques were used to generate thematic maps of various soil attributes and soil quality indices. Sediment deposition was observed in all panchayats, while highest deposition of sand and silt were observed in Aranmula and Thumbamon panchayats. The flood did not cause much alteration in the soil texture of AEU 9 of pathanamthitta. The dominant textural class was loam. The particle density and bulk density of soil ranged from 2.07 to 2.45 and 0.87 to 1.76 Mg m -3 respectively. More than 89 per cent of the soils showed porosity in the range of 50 to 80 per cent. The soil moisture content ranged between 15.2 to 50.8 per cent. The water holding capacity and water stable aggregates ranged from 25.4 to 62.4 per cent and 38.6 to 68.5 per cent respectively. 137The electrical conductivity of soil ranged between 0.05 and 0.40 dS m -1 . Post flood soil showed an increase in the organic carbon status of the soil. Majority (95 %) of soil comes under medium and high organic carbon status after flood. About 54.7 per cent of the soils are medium in available N content. Available phosphorus content varied between 8.10 and 104 kg ha -1 with a mean of 31.9 kg ha -1 and available potassium varied between 78.7 and 493 kg ha -1 with a mean of 246 kgha -1 . The post flood soils are adequate in available sulphur (92 %) and deficient in boron status (100 %). The soil quality analysis revealed that majority of soils had high soil quality index (86.7%). Land quality index was very low in 64 % of soils while 32 % samples showed low land quality index. Nutrient index for nitrogen was low in most of the panchayats, medium and high for phosphorus, potassium and organic carbon. The results of the study revealed that most of the soil became strongly acidic after flood. Organic carbon, potassium, phosphorus and sulphur are high and medium status while nitrogen is low in most of the panchayats. Deficiency of calcium and magnesium increases after flood. The entire study area showed deficiency of boron. The results outline the need for regular liming to control soil acidity and alleviate calcium deficiency. It is also suggested to supplement magnesium and boron to improve soil quality.ThesisItem Open Access Assessment of soil quality in the post - flood scenario of AEU 9 in Pathanamthitta district of Kerala and generation of GIS maps(Department of Soil Science and Agricultural chemistry, College of Agriculture, Vellayani, 2021) Shafna, S H; KAU; Gladis, RA study entitled “Assessment of soil quality in the post-flood scenario of AEU 9 in Pathanamthitta district of Kerala and generation of GIS maps” was carried out during 2018-20 with the objective to evaluate the soil quality in the flood affected areas of AEU 9 of Pathanamthitta district, to work out the soil quality index and to generate maps of various soil attributes and quality indices using GIS techniques. Survey conducted to identify the flood affected areas in AEU 9 of Pathanamthitta district revealed that the flood affected panchayats includes Kaviyur, Thumbamon, Kulanada, Thottapuzhassery, Kallupara, Mezhuvely, Panthalam, Kozhanchery, Aranmula, and Mallapally. All these panchayats were severely affected by flood havoc and submergence that occurred in Manimala, Pamba and Achankovil rivers during August 2018. A total of seventy five geo referenced surface soil samples were collected from the flood affected panchayats and analyzed for various physical, chemical and biological attributes. Minimum data set of soil indicators for computing soil quality was selected using principal component analysis. The selected parameters were sand content, bulk density, available B, available S, available K, available Mn and organic carbon. Scores and weights were assigned to each selected indicator, and computed the soil quality index. GIS techniques were used to generate thematic maps of various soil attributes and soil quality indices. Sediment deposition was observed in all panchayats, while highest deposition of sand and silt were observed in Aranmula and Thumbamon panchayats. The flood did not cause much alteration in the soil texture of AEU 9 of pathanamthitta. The dominant textural class was loam. The particle density and bulk density of soil ranged from 2.07 to 2.45 and 0.87 to 1.76 Mg m -3 respectively. More than 89 per cent of the soils showed porosity in the range of 50 to 80 per cent. The soil moisture content ranged between 15.2 to 50.8 per cent. The water holding capacity and water stable aggregates ranged from 25.4 to 62.4 per cent and 38.6 to 68.5 per cent respectively. 137The electrical conductivity of soil ranged between 0.05 and 0.40 dS m -1 . Post flood soil showed an increase in the organic carbon status of the soil. Majority (95 %) of soil comes under medium and high organic carbon status after flood. About 54.7 per cent of the soils are medium in available N content. Available phosphorus content varied between 8.10 and 104 kg ha -1 with a mean of 31.9 kg ha -1 and available potassium varied between 78.7 and 493 kg ha -1 with a mean of 246 kgha -1 . The post flood soils are adequate in available sulphur (92 %) and deficient in boron status (100 %). The soil quality analysis revealed that majority of soils had high soil quality index (86.7%). Land quality index was very low in 64 % of soils while 32 % samples showed low land quality index. Nutrient index for nitrogen was low in most of the panchayats, medium and high for phosphorus, potassium and organic carbon. The results of the study revealed that most of the soil became strongly acidic after flood. Organic carbon, potassium, phosphorus and sulphur are high and medium status while nitrogen is low in most of the panchayats. Deficiency of calcium and magnesium increases after flood. The entire study area showed deficiency of boron. The results outline the need for regular liming to control soil acidity and alleviate calcium deficiency. It is also suggested to supplement magnesium and boron to improve soil quality.ThesisItem Open Access Utilisation of potassium rich crop residues for retention of potassium in lateritic soil(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellanikkara, 2021) Sreelakshmi, P; KAU; Durga Devi, K MPotassium is a versatile vital nutrient for regular plant and animal growth and development. It is regarded as a "quality nutrient" because of its multifunctional role in metabolism. Kaolinite clay minerals prevalent in lateritic soils of Kerala, have lower activity and prevent the retention of available forms of potassium. Potassic fertilisers are often overlooked in fertiliser schedules due to their high unsubsidized cost. There are some K rich organic sources that are ignored by the farmers and are left or burnt in the soil. The utilisation of organic K resources like rice straw and plantain compost made from banana wastes are regarded good alternatives for synthetic potassic fertilisers. The present investigation consisted of three experiments viz., (i) assessment of decomposition dynamics of rice straw and its K release, (ii) K adsorption study on rice straw and prepared plantain compost and (iii) an incubation study in lateritic soil with different sources of potassium. The decomposition rate of rice straw has increased with the period of its incubation and it showed only a partial decomposition of 51.9 % at 90 days due to the presence of more amount of lignin, cellulose and hemicellulose content which takes more time for its degradation. The potassium release rate increased to 84.28 % at 90 days of its decomposition. The adsorption study on rice straw with different levels of KCl solution at different periods of decomposition revealed that as the solution concentration increased, the quantity of K adsorbed on rice straw also increased along with the increase in incubation period. Similarly, plantain compost that was prepared using vermi technology also showed an increased trend in the value of quantity of K adsorbed on compost as the KCl concentration increased. Because of its smaller particle size and larger surface area, plantain compost has stronger adsorption and buffer power than rice straw. Rice straw with potash (T1), plantain compost with potash (T2), wood ash, FYM with potash (T3), rice straw with lime and potash (T4), plantain compost with lime and potash (T5), wood ash, FYM with lime and potash (T6), lime and potash (T7), potash alone (T8), and absolute control (T9) treatments were used in the incubation study. The physico-chemical characteristics of soil such as pH, EC, organic carbon, available N, P, Ca, Mg, S, Fe, Cu, Zn, and Mn were determined at initial and final days of incubation. Data on the different fractions of soil K indicated that the treatment containing rice straw with lime and Muriate of potash (T4) showed the higher value of total K, exchangeable K and non-exchangeable K after 90 days of incubation. The reason might be that the presence of more inter planar sites in rice straw has trapped the K+ ions in fixed form since the material is not completely decomposed. At the same time incorporation of rice straw has enhanced the CEC of the soil thus enhancing greater adsorption of exchangeable K from unavailable forms by mass effect. The current study showed that combining organic K resources with lime and K fertilisers resulted in significant increases in soil K fractions. Integrated application of rice straw with lime and K fertiliser can be considered as the best method for long-term cultivation because it has the ability to retain and release more K, particularly nonexchangeable, exchangeable, and total K, allowing for continuous uptake of K by the crops for normal growth and development. The usage of plantain compost in combination with lime and Muriate of potash has resulted in increased availability of K as well as micronutrients by maintaining favourable pH.ThesisItem Open Access Assessment of soil quality in the post flood scenario of AEU 13 in Palakkad district of Kerala and mapping using GIS techniques(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2020) Gadha, V P; KAU; Thulasi, VSoil quality is the capacity of the soil to function within its ecosystem boundaries to sustain biological productivity, maintain environmental quality and promote plant and animal health. It primarily depends on its dynamic properties which significantly change under environmental disturbances. The flood of August 2018 witnessed by Kerala not only caused havoc to life and properties but also triggered alarming changes in soil quality. Two types of flood damages were noticed throughout the state either due to river overflow and water logging or by caustic landslides. The parts of AEU 13 (Northern foothills) in Palakkad district consisting of low hills with undulating topography was affected both by river overflow and landslides. The study area in AEU 13 comprises of ten panchayats belonging to Mannarkkad and Sreekrishnapuram block panchayats. Heavy overflow of Nellippuzha, Kunthippuzha and Kanjirappuzha rivers in the area caused destruction of field crops and sand and silt deposition on their banks. Landslides from Kalladikkodan and Anangan hills resulted in complete demolishment of the nearby areas in Karimba, Kottopadam and Kanjirappuzha panchayats. The present study was undertaken to assess the soil quality in the flood affected areas of AEU 13 in Palakkad district and to develop maps on soil characters and quality using GIS techniques. The soils of AEU 13 are poor in organic matter, strongly acidic, dominated by low activity clays and sesqui-oxides and suffer from multi-nutrient deficiencies. One hundred and one georeferenced soil samples were collected from the flooded and landslide affected areas, processed and analyzed for different chemical, physical and biological properties. The results showed variation in all soil attributes except in available B, exchangeable acidity and electrical conductivity. The bulk density ranged from 1.11 Mgm-3 to 1.69Mgm-3 with 54 percentage of samples coming above 1.4 Mgm-3. Regarding particle density, seventy five percentage of the samples had values greater than 2.4 Mgm-3, whereas porosity and water holding capacity were in an optimum range. All the samples were acidic with pH ranging from 3.9 (Alanallur) to 6.8 (Mannarkkad), but with low exchangeable acidity. Soil organic carbon varied from 0.38 (Mannarkkad) to 1.78 percent (Kottopadam) with40percentage of samples coming under low category. Seventy five percentage of the samples were low in available N with an average value of 238.2 kg ha-1 for the area. The available P and K were high in the area with 67 and 74 percentage of samples coming under high category for available P and K respectively. Available Ca was sufficient (>300 mg kg-1) in 70 percentage of samples while available Mg was deficient (2.33) with respect to available P and K. Pearsons correlation matrix showed a strong positive correlation between organic C and available N and negative correlation between OC and bulk density. Soil pH is negatively correlated with exchangeable acidity and positively correlated with available Ca, Mg and K. When compared with the pre-flood analytical data collected from District Soil Testing Laboratory (DSTL), Pattambi, proportion of soil samples coming under medium and high category of soil organic carbon increased after flood, which may be due to organic matter deposition. There was a reduction in available Ca and Mg after flood which might be due to leaching and infiltration loss. The pre-flood data collected as well as the analytical results of the present study indicated deficiency of B and sufficiency of cationic micronutrients like Fe, Cu, Mn and Zn in AEU 13. Assessment of the present status of the land slide affected soils indicated higher bulk density and particle density than that of flood affected soils of the study area which may be due to the addition of heavier minerals during land slide from subsurface areas to topsoil. Available S, Fe and Mn were also higher in soil samples collected from landslide affected areas. For developing minimum data set (MDS), principal component analysis (PCA) was performed for 22 attributes and resulted in seven principle component groups. Soil quality index (SQI) was worked out using non linear scoring method. The MDS comprised of eight attributes with available Ca and bulk density having highest contribution to SQI. Soil quality index ranged from 0.408 (Karimba) to 0.539 (Kumaramputhur). The average relative soil quality index (RSQI) of flood affected soils of AEU 13 in Palakkad district was 43.92 percent which is rated as low. Only 20 % of the soil samples collected from the area had medium RSQI values. When averaged over different panchayats, Alanallur (48.67 percent) had highest and Karimba had lowest RSQI (37.36 percent). High bulk density and particle density and low available N and B might be the reason for low soil quality observed throughout the area. The soil quality of the post flooded soils in the AEU 13 can be improved by adopting appropriate soil health management strategies with major thrust on site specific and integrated nutrient management practices.ThesisItem Open Access Assessment of soil quality in the post flood scenario of AEU 15 (northern high hills) in Thrissur district of Kerala and mapping using GIS techniques(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2020) Mili, M; KAU; Betty, BastianAgro-ecological unit 15 (AEU 15) represents the Northern High Hills which is characterised by long dry spells (4 months in a year), a tropical humid monsoon type climate with an average annual precipitation of 3459.5 mm and a mean annual temperature of 26.20 C. The hilly terrains have deep, well drained clayey soils rich in organic matter, strongly acidic and low in bases whereas the valleys have deep, imperfectly drained acid clayey soils. The August floods of 2018 had caused great havoc to life, property and agriculture of the state causing drastic changes in soil properties thereby affecting soil quality and fertility and thereby its productivity. The study entitled ‘Assessment of soil quality in the post flood scenario of AEU 15 (Northern High Hills) in Thrissur district of Kerala and mapping using GIS techniques’ was therefore conducted with an objective to assess soil quality in the designated AEU and prepare thematic maps using GIS. A total of one hundred and four geo-referenced soil samples were collected from five grama panchayats namely Pazhayannur, Pananchery, Puthur, Varantharappilly and Mattathur, which were affected by floods. These soils were characterized for physical, chemical and biological properties. The bulk density values ranged from 0.83 to 1.74 Mg m-3 and 80.77% of the soils had a bulk density greater than 1.20 Mg m-3. Porosity ranged between 30 to 60% in 99.04 per cent of the samples and 83.65 per cent of the samples had maximum water holding capacity in the range of 30-50 %. Among the soil samples, 53.84 per cent belonged to moderately acidic /slightly acidic/neutral category (pH ≥ 5.6). All the soils had electrical conductivity less than 1.0 dS m-1. Exchangeable acidity was greater than 1 cmol kg-1 in 81.73% of the samples. In case of organic carbon, 39.40 per cent of the samples had low (25.0 kg ha-1) in all the samples. In the case of available potassium, 58.65 per cent of the samples had medium (116.0 -275.0 kg ha-1) and 31.73 per cent had high (>275.0 kg ha-1) contents. Available calcium content was sufficient (>300 mg kg-1) in 99.04 per cent of the samples. Deficiency of available magnesium (2.33) with respect to available phosphorus. Using principal component analysis (PCA), seven principal components with eigen values greater than one were extracted and eight soil parameters were identified as the key indicators determining the soil quality of the area. The key indicators formed the minimum data set (MDS) viz., porosity, water holding capacity, pH , available nitrogen, potassium, magnesium, manganese and boron. Non linear scoring method was adopted to assess soil quality. The products of score and weightage factor of the MDS parameters were summed up to obtain a soil quality index (SQI) of that particular site. Soil quality indices were rated using relative soil quality index (RSQI). It was found that 79.81 per cent of the soil samples had a medium relative soil quality index . Organic carbon showed a significant positive correlation with available nitrogen, zinc, magnesium, copper, maximum water holding capacity and dehydrogenase activity. In comparison with preflood data (GoK, 2013) where all samples were found to be acidic (pH 4.50- 6.50), 8.65% of the post flood soils exhibited neutral range of pH. Organic carbon, available nitrogen, sulphur and boron became more deficient after the floods. But there was an increase in the content of nutrients like available phosphorus, potassium, calcium, magnesium, copper and zinc. Bulk density of soils also increased after the floods. The soil quality of post flood soils in the AEU have to be improved by adopting site specific and integrated nutrient management practices in a comprehensive manner including fertilizers, organic sources and biofertilizers.ThesisItem Open Access Assessment of soil quality in the post floods scenario of AEU 5 and AEU 9 of Ernakulam district of Kerala and Mapping using GIS Techniques(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2020) Neha, Unni; KAU; Sreelatha, A KKerala state witnessed large scale devastating flood in 2018 due to excess rainfall, causing significant damage to agricultural sector and human life. One of the most affected districts was Ernakulam, especially AEU 5 and AEU 9. The AEU 5 - Pokkali lands, represent the lowlands, often below sea level, in coastal areas of Ernakulam district and extending to parts of Thrissur and Alappuzha districts. The soils are hydromorphic, often underlain by potential acid-sulphate sediments with unique hydrological conditions. Seawater inundation is not controlled and hence soils are acid-saline. The AEU 9 - south central laterites represent midland laterite terrain with typical laterite soils. The study aimed at the assessment of soil quality in the post flood scenario of AEU 5 and AEU 9 in Ernakulam district and to develop maps on soil characters and quality using GIS techniques and to workout soil quality index (SQI). For this purpose 100 geo-referenced soil samples were collected from different panchayats of AEU 5 and AEU 9 in Ernakulam district and were characterized for physical, chemical and biological properties. The Pokkali soils recorded low bulk density whereas porosity, water holding capacity and soil moisture were found high. Available N content was medium to high, available phosphorus and potassium was high in the soil. Among the secondary nutrients, available Ca and S were found sufficient for majority of the samples, while a deficiency of available Mg was noticed in Pokkali soils. In AEU 9, the soil pH varied from 5.01 to 7.69 and all the soils had an electrical conductivity less than 1.0 dS m-1. Organic carbon was noticed low to medium in the soils. Available N content was medium for 87 per cent of the samples, whereas all the samples were high in available P content. Available K was recorded low to medium values in AEU 9. Soil quality index was calculated using principal component analysis (PCA). There are three main steps involved in the soil quality index method which includes (i) selection of a minimum data set (MDS) of indicators (ii) formation of the MDS indicators and scoring of each indicators (iii) computation of index of soil quality. For developing minimum data set, principal component analysis (PCA) was performed for 23 soil attributes and resulted in 7 PCs. The indicators with high loading factors in each PCs were selected to develop minimum data set (MDS). MDS constituted 8 attributes for AEU 5 and 9 attributes for AEU 9 respectively. After the development of MDS, the soil indicators were converted to unit-less scores ranging from 0 to 1 using non-linear scoring function methods. Three types of scoring curves were used: i) more is better, ii) less is better, iii) optimum curve. Soil quality index ranged from 0.42 in Nayarambalam to 0.76 in Vadakkekkara in AEU 5, and 0.39 in Edathala to 0.92 in Aluva in AEU 9. The highest RSQI value was recorded in Aluva (69.7%) and the lowest in Edathala (29.55%) under AEU 9. In AEU 5 the highest RSQI was obtained in Vadakkekkara (71.58%) and the lowest in Nayarambalam (37.06%). Nutrient indices of flood affected areas in AEU 9 were low with respect to organic carbon and available potassium, medium with respect to available nitrogen and high with respect to available phosphorus. Nutrient index was high for nitrogen, phosphorus, potassium and organic carbon in AEU 5. Significant positive correlations were observed between organic carbon and available nitrogen, organic carbon and soil moisture content. Negative correlation existed between bulk density and porosity, organic carbon and bulk density in both AEUs. The present study revealed that soil fertility and productivity have been disturbed after the floods. In AEU 9 available potassium was found decreased after the flood. Prior to flood Kottuvally, Elamkunnapuzha, Edavanakkad and Kuzhuppilly panchayats in AEU 5 were medium in relative soil quality index (Joseph, 2014) and post flood assessment showed that these panchayats shifted to poor relative soil quality index.ThesisItem Open Access Assessment of soil quality in the post flood scenario of AEU 4 in Kottayam district of Kerala and generation of GIS maps(Department of Soil Science and Agricultural Chemistry, Vellayani, 2020) Anusha, B; KAU; Sailajakumari, M SThe study entitled ‘Assessment of soil quality in the post-flood scenario of AEU 4 in Kottayam district of Kerala and generation of GIS map’ was conducted with the objective to assess the soil quality of post-flood soils, to work out soil quality index (SQI) and to develop GIS maps based on soil characters and quality. Preliminary survey was conducted in four different blocks of AEU 4 in Kottayam district viz. Vaikom, Kaduthuruthy, Ettumanoor and Madapally. Seventy-five geo-referenced surface soil samples were collected from eighteen panchayats selected based on the survey. Paddy, banana, vegetables, coconut and nutmeg were found to be the major crops cultivated in the study area. Ninety-four percentage of farmers in the surveyed area were small and marginal mostly following conventional method of nutrient management. The soil samples collected from the eighteen panchayats were analysed for various physical, chemical and biological attributes. The physical attributes included bulk density, particle density, porosity, water holding capacity, soil moisture, soil texture, depth of sand/silt/clay deposition, aggregate analysis. Soil texture for majority of the samples (68.8 percent) was sandy clay loam with water holding capacity ranging from 20.6 to 68.8 per cent. Bulk density of 50.7 per cent of samples recorded a value less than 1.2 Mg m-3 with a mean value of 1.2 Mg m-3. Particle density of 73.3 per cent samples were less than 2.2 Mg m-3. Depth of sand/silt/clay deposition was not much significant in the study area. The chemical parameters analysed were pH, EC, organic carbon, available macronutrients and boron (micronutrient). More than 90 per cent of samples were in the acidic range with 6.67 per cent as ultra-acidic, 17.30 per cent as extremely acidic, 20 per cent as very strongly acidic, 14.70 per cent as strongly acidic, 14.6 per cent as moderately acidic and 7.61 as slightly acidic. EC value was less than 1 dS m-1 for 89.3 per cent of the samples. Organic carbon was high in 58.7 per cent samples analysed. Availability of nitrogen was found to be low in 78.7 per cent of samples, phosphorus and potassium was high in 54.7 per cent and 40 per cent samples respectively. Among the secondary nutrients, available calcium was adequate in 88 % of samples while available magnesium was sufficient in 58.7 % samples. Sulphur availability was found to be adequate in 81.3 per cent samples and boron was deficient in 78.7 per cent samples. Activity of acid phosphatase was also analysed as a biological attribute. Activity of 41.3 percentage sample were in the range of 10 to 25 μg p-nitrophenol g-1 soil h-1 Nutrient indices were calculated from the analysed data. The analysed data was also used to set up a minimum dataset (MDS) by employing principal component analysis (PCA). Principal component analysis of 20 attributes resulted in a MDS containing seven attributes (organic carbon, available N, P, K, Ca, per cent sand and per cent silt). By giving scores and weightage to each component in the MDS, soil quality index (SQI) was worked out. The relative value for soil quality index (RSQI) was used to categorize the soil into low, medium and good quality. GIS techniques were used to prepare thematic maps of various soil parameters and soil quality indices. Simple correlations were also worked out among various analysed parameters. Nutrient index was high for organic carbon, low for available nitrogen while it was medium for available phosphorus and potassium. Compared to the pre flood data (KSPB,2013) soil acidity was increased as there was an increase in percentage samples in ultra-acidic, moderately acidic and strongly acidic range, an increase in organic carbon, available potassium, calcium and magnesium were observed. Even though the availability of phosphorus and sulphur were high in the AEU, percentage of samples in low fertility class was increased compared to pre-flood data. However, availability of boron was decreased and the per cent deficient soil samples considerably increased in the post-flood scenario The study indicated that RSQI in the majority of soils of AEU 4 of Kottayam district was medium and land quality index was very low to low. The study recommends the site specific adoption of soil management strategies for the control of soil acidity, applications of soil ameliorants, micronutrients such as B for maintaining soil health and quality in the AEU 4 regions of Kerala.
