Loading...
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.
Browse
27 results
Search Results
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 Dissipation and distribution of fipronil, carbosulfan and their metabolites in banana var. Nendran (AAB) and soil(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2021) Visveswaran, S; KAU; Thomas, GeorgeThe study entitled “Dissipation and distribution of fipronil and carbosulfan and their metabolites in banana (Musa spp) and soil” was carried out at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani during the period from August 2016 to April 2017. The objective was to assess the dissipation, metabolism and persistence of fipronil and carbosulfan in banana, cv. Nendran (AAB), grown under red loam soils (AEU 8-southern laterites) of College of Agriculture, Vellayani, and its impact on soil organisms. Banana variety Nendran, grown as per package of practices recommendations, KAU in randomized block design at the Instructional Farm, Vellayani, with five treatments viz., T1- absolute control (No application of carbosulfan and or fipronil), T2- recommended practice of 30 mg ai of fipronil per plant per application, applied 3 times on 0, 60 and 150 days of planting, T3 – double dose of T2, T4- recommended practice of 400 mg ai of carbosulfan per plant per application, applied 3 times on 0, 60 and 150 days of planting and T5- double the dose of T4. Samples viz, soil, leaves, fingers bunches and flower bud, central core of pseudo-stem and corm were collected and analyzed for residue at definite time intervals. The residue estimation of the target pesticide molecules and their toxic metabolites were performed by adopting standard extraction and clean up procedure viz., conventional acetone extraction followed by hexane partitioning as well as by QuEChERS method. Method validation was conducted by spiking with analytical standards from which recovery, (accuracy 70-120% of spiked values), standard deviation of recoveries, RSD value (below 20%), linearity (calibration curve), for the adopted method were worked out and compared for compliance. Acetonitrile extracted samples were analyzed using “Waters Acuity UPLC 137 system” with suitable column and then subjecting the effluent to triple quadrupole API 3200 MS/MS system equipped with electrospray ionization interface (ESI) operating in required mode as per the molecule. Extraction using QuEChERS method gave satisfactory values for validation parameters and hence adopted for the studies. The presence of carbosulfan in the 1st to 4th leaves till day 20th and subsequent dissipation pattern prediction for BDL in 22.5 day indicated that, at recommended dose of application, it is not safe to use the leaves within 23 days of application for serving or food packing (as commonly practiced in many households of Kerala). Sample matrices revealed the presence of metabolites each for fipronil and carbosulfan with variation from below detectable limit (BDL) to a highest content of 3.804 μg/g carbosulfan at 2 hours of application in the soil. Blossom bud, flower bract alone, bunch on 15th day of emergence, bunch on 30th day of emergence, peel, bunch on harvest, pseudo stem and corm did not register any detectable level of fipronil or carbosulfan and their metabolites and even with an additional application of treatment on the day of bunching also did not register any detectable level of fipronil or carbosulfan and their metabolites. Residue of fipronil and their toxic metabolites in the first, second and third leaves of banana on penultimate day of completion of pre-bunching application was found to be below the detectable levels throughout the period of sampling and this may be attributed to low absorption, fast metabolism and mobility. However, on 40th day the fipronil was detected in the 4th leaf to the extent of 0.034 μg g-1 and was not detectable on 50th day. Metabolites of Carbosulfan residue existed in the first, second and third leaves between 5th and 20th day and it dissipated to below detectable limit on 40th day of application. The content of residue under treatment T5 was distinctly higher than T4 during these periods and dissipated to BDL on 25th day. 138 In soil, the fipronil though dissipated to BDL before 50th day, persisted from 2 hours of application till 40th day. However, carbosulfan and its metabolites were early to dissipate to BDL on 7th day of completion of application. Sample in experiment with 5 times the recommended dose of application as injection into pseudostem at the time of bunch emergence also did not record any residue above detectable level in the flower bud, flower bract alone, bunch on 15th day of emergence, bunch on 30th day of emergence, peel, bunch on harvest and pseudostem. Soil urease activity on 10th day was significantly influenced by the treatment where T1, T3 and T5 are significantly lower than T2 and T4. However, dehydrogenase activity and acid phosphatase activity were not significantly influenced by the treatment. Bacterial population was higher in T1. Treatments were found to significantly influence the weight of blossom bud on dehorning, pseudostem, bunches and corm. Other biometric parameters were not influenced by the treatment. The above results show complete dissipation of fipronil and carbosulfan to safe limits in soil and banana leaf, when applied as per package of practices recommendation for banana cultivation (fipronil 30 mg a.i. and carbosulfan 400 mg a.i. per plant applied thrice viz., on 0, 60 and 150 days of planting), within 50 and 23 days of application. Also, the application of fipronil and carbosulfan as per the above dose in no way results in the accumulation of residue on any of the edible plant parts of banana and hence it is safe for human consumption.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 Nutrient dynamics and crop productivity in lowland lateritic soil (aeu 10) under rice residue management practices(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellanikkara, 2021) Amritha, K; KAU; Jayasree Sankar, SThe present investigation was undertaken at College of Agriculture Vellanikkara, Kerala Forest Research Institute Peechi, and Agricultural Research Station Mannuthy during 2017-2020. The experiment comprised of characterization of rice residues and their products for physical and chemical properties, an incubation experiment to study the kinetics of carbon mineralization, and a field experiment to evaluate the efficacy of rice residues and their products on lowland rice. Straw and husk, the important residues produced during the cultivation and processing of rice, respectively was procured from farmer’s field and further materials required for the research work viz., vermicomposted rice straw (VRS), vermicomposted rice husk (VRH), rice straw biochar (RSB), and rice husk biochar (RHB) were produced from the straw (RS) and husk (RH) using vermitechnology and pyrolysis. Recovery from vermicomposting was more (74.38 % for VRS and 70.03 % for VRH) than when the residues were converted into biochar through pyrolysis (19.86 % for RSB and 38.00 % for RHB). Vermicomposting and pyrolysis reduced the bulk density of raw materials. Rice residues and their products were alkaline, with biochar exhibiting the highest level of alkalinity (9.24 for RSB and 9.20 for RHB). The electrical conductivity increased both by vermicomposting and pyrolysis. Straw was comparatively superior to the husk in respect of C, N, K, Ca, Mg, Fe, Mn, Cu, and Zn. However, husk was superior in P, S, B, Si, cellulose, and lignin. Vermicomposting helped to concentrate the nutrients viz., N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, B, and Si while reducing that of carbon, cellulose and lignin thereby narrowing down the C: N ratio. However, C: N ratio increased upon pyrolysis. Surface morphology of rice residues and their products were studied using scanning electron microscope (SEM). The SEM micrographs of straw and husk exhibited a complex morphology with cell wall composition. SEM micrograph of VRS showed highly fragmented, disaggregated and porous structure which could not be visualised in VRH, may be because the technology of composting using earthworms was more suited to decomposing rice straw than its husk. The SEM analysis showed that the structure of biochar was porous, fragmented and particles gave a broken or distorted appearance thus resembling the plant structure. The structural chemistry of rice residues and their products were analysed using fourier transform infra red spectrometer (FT-IR). Each peak is characteristic of correspondingfunctional group and it clearly explained the presence of C, H, O, N, and Si in the residues and products. Silicon, a major component in the chemical structure of rice material was illustrated by Si-O-Si and Si-H bond in FT-IR spectra. Vermicompost had significant level of nitrogen rich compounds and low level of aliphatic or aromatic carbon compounds compared to biochar, as confirmed by the FT-IR analysis. The FT-IR spectra of RSB and RHB revealed its aromatic and recalcitrant nature. The incubation experiment was conducted for 110 days at 15, 25, 35 and 45 oC to study the kinetics of carbon mineralization in lateritic soil over time, wherein the CO 2 evolution was determined at frequent intervals and the data were used for determination of carbon mineralization and mineralization kinetics. Lateritic soils (100g) collected from Agricultural Research Station Mannuthy, were treated with rice residues and their products (5t ha -1 ), FYM (5 t ha -1 ), and soil test based nutrient recommendation. An absolute control without the addition of organic/inorganic materials was also maintained. Dehydrogenase enzyme assay, enumeration of microbial population, and fractions of carbon were also undertaken at the end of incubation. Results of incubation experiment revealed that the amount of CO 2 –C mineralized during incubation increased with rise in temperature in all the treatments. The VRS treated soils registered higher mineralizable carbon at 15, 25, 35 and 45 oC. The rate of decomposition reaction was highest in soils that are treated with VRS and FYM. The highest activation energy was found in RHB amended soil (12.79 kJ mol -1 ) followed by RSB treated soil (12.71 kJ mol -1 ). Q 10 values represent the temperature dependency of the reaction. The results showed that all treatments had Q 10 values less than one. After incubation experiment, dehydrogenase activity as well as microbial population was found to decrease at 45 oC compared to the values at lower temperature. Comparatively, higher dehydrogenase activity and microbial population was registered in soils treated with VRS. The soils treated with VRS exhibited highest water soluble carbon (WSC), hot water extractable carbon (HWEC), microbial biomass carbon (MBC), and permanganate oxidizable carbon (POXC). However, biochar amended soils (RHB and RSB) registered higher value of total carbon. A field experiment was carried out to evaluate the efficacy of rice residues and their products in lowland with rice variety Uma as the test crop. The experiment consisted of ninetreatments with three replications viz., absolute control (T 1 ), Adhoc KAU organic POP (T 2 ), and treatments T 3 to T 9 comprised of soil test based nutrient recommendation along with FYM (T 3 ), VRH (T 4 ), VRS (T 5 ), RHB (T 6 ), RSB (T 7 ), RH (T 8 ), and RS (T 9 ) at 5t ha -1 . At weekly intervals Eh and pH were monitored. The soil and plant samples were collected at different stages of rice to analyse the effect of treatments on soil physical and chemical properties, fractions of nutrients in soil, nutrient content in plant, soil enzyme activity, and growth, yield and yield attributes of rice. Results of field experiment revealed that the application of residues and its products had a profound influence in lowering redox potential. The alkaline nature of rice residues and their products resulted in higher pH of experimental soil. Physical properties of post-harvest soil was improved by the application of T 6 and T 7 (soil test based nutrient recommendation + RHB and RSB). The application of T 5 (soil test based nutrient recommendation + VRS at 5 t ha -1 ) was superior in increasing the nutrient status of post-harvest soil viz., C, N, P, Ca, Mg, S, Fe, Mn, Zn, and Si. While, K content was superior in T 7 (soil test based nutrient recommendation + RSB at 5 t ha -1 ). Soils receiving combined application of soil test based nutrient recommendation and VRS at 5 t ha -1 (T 5 ) recorded the highest WSC, HWEC, MBC, POXC, inorganic-N and P fractions, fractions of Ca and Mg at all the stages of crop. However, total- C, total hydrolysable-N, organic-P, and Si fractions were higher in biochar amended plots. Soil receiving joint application of soil test based nutrient recommendation +RSB at 5 t ha -1 (T 7 ) was statistically superior in fractions of K at all stages. Enzyme activity (dehydrogenase, urease, and acid phosphatase) was found to be highest in T 5 (soil test based nutrient recommendation + VRS at 5 t ha -1 ), and it followed an increasing trend upto panicle initiation and thereafter it decreased in all treatments. The uptake of N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B and Si were also highest in T 5 . With respect to the growth, yield and yield attributes of rice, application of soil test based nutrient recommendation + VRS at 5 t ha -1 (T 5 ) had superior effect. To conclude, the study has brought out the tremendous potential of rice straw and husk based biochar in improving soil physical properties and in elevating the total carbon content. However, the integration of soil test based nutrient recommendation with vermicompostedrice straw at 5t ha -1 (T 5 ) proved outstanding in augmenting soil fertility and crop productivity in the highly weathered, nutrient poor acidic lateritic soils.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 Nutrient dynamics and crop productivity in lowland lateritic soil (aeu 10) under rice residue management practices(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellanikkara, 2021) Amritha, K; KAU; Jayasree Sankar, SThe present investigation was undertaken at College of Agriculture Vellanikkara, Kerala Forest Research Institute Peechi, and Agricultural Research Station Mannuthy during 2017-2020. The experiment comprised of characterization of rice residues and their products for physical and chemical properties, an incubation experiment to study the kinetics of carbon mineralization, and a field experiment to evaluate the efficacy of rice residues and their products on lowland rice. Straw and husk, the important residues produced during the cultivation and processing of rice, respectively was procured from farmer’s field and further materials required for the research work viz., vermicomposted rice straw (VRS), vermicomposted rice husk (VRH), rice straw biochar (RSB), and rice husk biochar (RHB) were produced from the straw (RS) and husk (RH) using vermitechnology and pyrolysis. Recovery from vermicomposting was more (74.38 % for VRS and 70.03 % for VRH) than when the residues were converted into biochar through pyrolysis (19.86 % for RSB and 38.00 % for RHB). Vermicomposting and pyrolysis reduced the bulk density of raw materials. Rice residues and their products were alkaline, with biochar exhibiting the highest level of alkalinity (9.24 for RSB and 9.20 for RHB). The electrical conductivity increased both by vermicomposting and pyrolysis. Straw was comparatively superior to the husk in respect of C, N, K, Ca, Mg, Fe, Mn, Cu, and Zn. However, husk was superior in P, S, B, Si, cellulose, and lignin. Vermicomposting helped to concentrate the nutrients viz., N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, B, and Si while reducing that of carbon, cellulose and lignin thereby narrowing down the C: N ratio. However, C: N ratio increased upon pyrolysis. Surface morphology of rice residues and their products were studied using scanning electron microscope (SEM). The SEM micrographs of straw and husk exhibited a complex morphology with cell wall composition. SEM micrograph of VRS showed highly fragmented, disaggregated and porous structure which could not be visualised in VRH, may be because the technology of composting using earthworms was more suited to decomposing rice straw than its husk. The SEM analysis showed that the structure of biochar was porous, fragmented and particles gave a broken or distorted appearance thus resembling the plant structure. The structural chemistry of rice residues and their products were analysed using fourier transform infra red spectrometer (FT-IR). Each peak is characteristic of correspondingfunctional group and it clearly explained the presence of C, H, O, N, and Si in the residues and products. Silicon, a major component in the chemical structure of rice material was illustrated by Si-O-Si and Si-H bond in FT-IR spectra. Vermicompost had significant level of nitrogen rich compounds and low level of aliphatic or aromatic carbon compounds compared to biochar, as confirmed by the FT-IR analysis. The FT-IR spectra of RSB and RHB revealed its aromatic and recalcitrant nature. The incubation experiment was conducted for 110 days at 15, 25, 35 and 45 oC to study the kinetics of carbon mineralization in lateritic soil over time, wherein the CO 2 evolution was determined at frequent intervals and the data were used for determination of carbon mineralization and mineralization kinetics. Lateritic soils (100g) collected from Agricultural Research Station Mannuthy, were treated with rice residues and their products (5t ha -1 ), FYM (5 t ha -1 ), and soil test based nutrient recommendation. An absolute control without the addition of organic/inorganic materials was also maintained. Dehydrogenase enzyme assay, enumeration of microbial population, and fractions of carbon were also undertaken at the end of incubation. Results of incubation experiment revealed that the amount of CO 2 –C mineralized during incubation increased with rise in temperature in all the treatments. The VRS treated soils registered higher mineralizable carbon at 15, 25, 35 and 45 oC. The rate of decomposition reaction was highest in soils that are treated with VRS and FYM. The highest activation energy was found in RHB amended soil (12.79 kJ mol -1 ) followed by RSB treated soil (12.71 kJ mol -1 ). Q 10 values represent the temperature dependency of the reaction. The results showed that all treatments had Q 10 values less than one. After incubation experiment, dehydrogenase activity as well as microbial population was found to decrease at 45 oC compared to the values at lower temperature. Comparatively, higher dehydrogenase activity and microbial population was registered in soils treated with VRS. The soils treated with VRS exhibited highest water soluble carbon (WSC), hot water extractable carbon (HWEC), microbial biomass carbon (MBC), and permanganate oxidizable carbon (POXC). However, biochar amended soils (RHB and RSB) registered higher value of total carbon. A field experiment was carried out to evaluate the efficacy of rice residues and their products in lowland with rice variety Uma as the test crop. The experiment consisted of ninetreatments with three replications viz., absolute control (T 1 ), Adhoc KAU organic POP (T 2 ), and treatments T 3 to T 9 comprised of soil test based nutrient recommendation along with FYM (T 3 ), VRH (T 4 ), VRS (T 5 ), RHB (T 6 ), RSB (T 7 ), RH (T 8 ), and RS (T 9 ) at 5t ha -1 . At weekly intervals Eh and pH were monitored. The soil and plant samples were collected at different stages of rice to analyse the effect of treatments on soil physical and chemical properties, fractions of nutrients in soil, nutrient content in plant, soil enzyme activity, and growth, yield and yield attributes of rice. Results of field experiment revealed that the application of residues and its products had a profound influence in lowering redox potential. The alkaline nature of rice residues and their products resulted in higher pH of experimental soil. Physical properties of post-harvest soil was improved by the application of T 6 and T 7 (soil test based nutrient recommendation + RHB and RSB). The application of T 5 (soil test based nutrient recommendation + VRS at 5 t ha -1 ) was superior in increasing the nutrient status of post-harvest soil viz., C, N, P, Ca, Mg, S, Fe, Mn, Zn, and Si. While, K content was superior in T 7 (soil test based nutrient recommendation + RSB at 5 t ha -1 ). Soils receiving combined application of soil test based nutrient recommendation and VRS at 5 t ha -1 (T 5 ) recorded the highest WSC, HWEC, MBC, POXC, inorganic-N and P fractions, fractions of Ca and Mg at all the stages of crop. However, total- C, total hydrolysable-N, organic-P, and Si fractions were higher in biochar amended plots. Soil receiving joint application of soil test based nutrient recommendation +RSB at 5 t ha -1 (T 7 ) was statistically superior in fractions of K at all stages. Enzyme activity (dehydrogenase, urease, and acid phosphatase) was found to be highest in T 5 (soil test based nutrient recommendation + VRS at 5 t ha -1 ), and it followed an increasing trend upto panicle initiation and thereafter it decreased in all treatments. The uptake of N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B and Si were also highest in T 5 . With respect to the growth, yield and yield attributes of rice, application of soil test based nutrient recommendation + VRS at 5 t ha -1 (T 5 ) had superior effect. To conclude, the study has brought out the tremendous potential of rice straw and husk based biochar in improving soil physical properties and in elevating the total carbon content. However, the integration of soil test based nutrient recommendation with vermicompostedrice straw at 5t ha -1 (T 5 ) proved outstanding in augmenting soil fertility and crop productivity in the highly weathered, nutrient poor acidic lateritic soils.ThesisItem Open Access Effect of thermochemical organic fertilizer on soil carbon pools, nutrient dynamics and crop productivity in ultisols(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2021) Amrutha, S Ajayan; KAU; Manorama Thampatti, K CA study entitled “Effect of thermochemical organic fertilizer on soil carbon pools, nutrient dynamics and crop productivity in Ultisols” was conducted from 2018 to 2020 at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani with the objective to study the effect of thermochemical organic fertilizer on soil carbon pools, nutrient dynamics, their retention and leaching, and crop productivity in comparison with conventional organic fertilizers in Ultisols using tomato - amaranthus cropping sequence. The study includes production and characterization of organic fertilizers, leaching study using soil columns, an incubation experiment and field experiments using tomato - amaranthus cropping sequence. For the leaching study and incubation, the treatments were addition of FYM, ordinary compost (OC), vermicompost (VC), microbial compost (MC), unfortified (TOF) and fortified thermochemical organic fertilizer (F-TOF) @ 50 g per soil column/ pot and an absolute control. For the field experiment on tomato-amaranthus cropping sequence, the treatments were T 1 – FYM + POP recommendation of NPK, T 2 - FYM + soil test based recommendation of NPK (STBR), T 3 - OC + STBR, T 4 - VC + STBR, T 5 - MC + STBR, T 6 - TOF + STBR, T 7 - F-TOF + STBR, T 8 - F-TOF alone and T 9 - absolute control. The organic fertilizers required for the study viz., OC, VC, MC, TOF and F- TOF were produced from bio-waste from vegetable markets and food waste from college hostels and FYM was purchased. The physical and chemical properties of organic fertilizers were in accordance with the standards of FCO. VC, OC, MC and FYM were neutral to slightly alkaline in reaction while TOF and F-TOF were slightly acidic. The lignin content (27.9 %) and the carbon pools viz., TOC (43.90 %), WSOC (1642 mg kg -1 ), labile carbon (1776 mg kg -1 ) and recalcitrant organic carbon (32.45 mg kg -1 ) were highest for TOF followed by F-TOF. The N content was 391highest for MC (2.61 %), P for VC (1.36 %) and K (2.56 %), Ca (1.12 %), Mg (0.78 %), Zn (254 mg kg -1 ) and B (4.64 mg kg -1 ) for F-TOF while S (550 mg kg -1 ), Fe (9580 mg kg -1 ) and Pb (4.16 mg kg -1 ) for FYM. All the organic fertilizers contained Pb, but within permissible limit, while, Cd was not detected in any of them. The soil column study was conducted to assess the extent of leaching loss of nutrients from F-TOF amended soil in comparison with other organic fertilizers and their nutrient retention ability in soil. Soil columns amended with organic fertilizers in the surface layer were subjected to leaching on 1 st , 4 th , 8 th , 12 th , 16 th , 20 th and 24 th weeks with double the pore volume of water. During the leaching, the mineralized nutrients moved downwards and deposited at different depths in the soil column in accordance with their mobility and the rest was lost in leaching water. Leachates from organic fertilizer amended soils showed slightly acidic pH, which decreased up to 8 th week followed by an increase towards 12 th week. EC was highest at first week followed by a decrease towards 24 th week. The highest cumulative loss of N (172.34 mg L -1 ), Ca (273.86 mg L -1 ) and Mn (3.97 mg L -1 ) was from VC while that of P (7.22 mg L -1 ), K (333.36 mg L -1 ), Mg (144.41 mg L -1 ), Cu (0.080 mg L -1 ) and B (0.166 mg L -1 ) was from F-TOF. For S the loss (4.19 mg L -1 ) was highest from FYM, and Fe (4.71 mg L -1 ) and Zn (4.58 mg L -1 ) from OC. The leachate did not contain Pb and Cd. The leached soil in the soil columns maintained a higher level of nutrients compared to the level prior to the addition of organic fertilzers even after leaching for 24 weeks. In the surface soil, highest quantity of total N was retained by MC; P, Mn and Cu by VC and K, Ca, Mg, Zn and B by F-TOF while FYM retained highest quantity of S and Fe. Evaluating the available nutrient status of the leached soil, it was found that F-TOF had highest availability for K, Mg, S, Fe, Zn, Cu and B. Availability of P and Mn was highest in VC amended soil and Ca from MC. Availability of Pb and Cd were not detected in the leached soil. 392The incubation study for a period of 24 weeks revealed the nutrient release pattern of organic fertilizers. The peak release of most of the nutrients from organic fertilizers was from 8 th to 16 th week and for S it extended up to 20 th week. The availability of K, Ca, Mg, Fe, Zn and B was highest from F-TOF amended soil while VC maintained the highest values for P, Mn and Cu and FYM for S. The different fractions of B were highest for F-TOF amended soil and the peak was during 12 th week of incubation. Available Pb and Cd were not detected in the incubated soil. Organic fertilizers amended soil maintained a higher microbial count and exhibited a higher dehydrogenase activity compared to the control and the highest value was observed with F-TOF amended soil. During the field experiments, in the first cropping sequence, VC amended treatment T 4 (VC + STBR) recorded significantly highest fruit yield (40.97 t ha -1 ) for tomato followed by T 7 (F-TOF + STBR) while in the second cropping sequence F- TOF gave the highest yield which was statistically on par with VC. While for amaranthus, F-TOF recorded the highest yield during both the cropping sequences (24.62 t ha -1 and 26.89 t ha -1 , respectively) followed by VC and both the treatments were statistically on par in the second cropping sequence. The quality parameters of tomato and amaranthus were highest for the treatment T 7 (F-TOF + STBR) but was statistically on par with other treatments which received organic fertilizers along with POP or soil test based NPK fertilizers. Evaluating the economic benefits, the performance of VC was the best for the first tomato followed by F-TOF while for second tomato F-TOF was the best. For amaranthus, F-TOF performed best during both the sequences. When the overall B:C ratio for the whole cropping sequence was taken F-TOF was the best followed by VC. Uptake of N, P, K, Ca, Mg, S, Zn and B in tomato was highest for F-TOF while that of Fe, Mn, and Cu was for VC. For amaranthus, the uptake of N, P, K, Mg, Fe, Zn, Cu and B was highest for F-TOF for both the cropping sequences. Among the 393heavy metals tested only Pb was detected in plant parts and that too in roots only. For tomato, it was detected only in FYM treated plants while in amaranthus, all the treatments receiving organic fertilizers showed the presence of Pb. But the Pb content in the root was within the safe limit. The availability of Pb in the post-harvest soil was trace and there was no significant difference between the treatments. Cd was not detected in soil as well as plant samples. The continuous application of organic fertilizers had improved the physical, chemical and biological properties of the soil. At the end of the second cropping sequence, the lowest bulk density and highest water holding capacity was recorded by the treatment receiving F-TOF + STBR. The highest value for TOC, labile carbon, microbial biomass carbon and recalcitrant organic carbon in the post-harvest soil during the cropping sequence was maintained by F-TOF. The N pools, NH 4 -N, NO 3 - N, organic N and total N at the end of second cropping sequence was also highest for F-TOF. In the case of availability of P, S, Fe, Mn and Cu in the post-harvest soil, better performance was showed by VC while F-TOF showed higher availability for K, Ca, Mg, Zn and B. Biological properties are a better indication of soil health and application of VC, MC and F-TOF maintained a higher microbial load in soil. The highest dehydrogenase activity was maintained by F-TOF. Continuous application of F-TOF and TOF increased the carbon stock of surface and sub-surface soil than other organic fertilizers. F-TOF is superior to VC, OC, MC and FYM in terms of increasing carbon pools and carbon stock of the soil. The nutrient release was highest from F-TOF for most of the nutrients compared to other organic fertilizers, which might have resulted more leaching losses. However, the nutrient retention was also highest for F-TOF, even after the leaching for 24 weeks, suggesting a revisit on the rate and mode of fortification for F-TOF, popularly marketed in the trade name “Suchitha”. For crop production, the performance of F-TOF found equally good as that of vermicompost and was superior to FYM, OC and MC.
- «
- 1 (current)
- 2
- 3
- »