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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Open Access
Substrate impact on biogas production and manurial value of slurry
(Department of Soli Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2015) Anooja, C Lonappan; KAU; Beena, V I
The growing population of the world increases energy demand and waste generation. Due to lack of proper recycling technology, large quantities of biodegradable wastes are being produced. Biogas production is a good technology for mitigating both the problems. The slurry produced after biomethanation is a good manure which provides balanced nutrition for crops and improves soil quality. There are large varieties of biodegradable wastes which can be used as feed stock for biogas production. The quality and quantity of biogas and slurry generated are based on the nature and composition of feed stock. In order to find out an efficient substrate from the available substrates in Kerala and to determine manurial value of different types of slurry, the present study was undertaken at College of Horticulture, Vellanikkara during 2012 – 2014. To elucidate the impact of different substrates on biogas production, an experiment was laid out with three replications and six treatments viz., cow dung alone and co digestion of cow dung with poultry manure, goat manure, biodegradable house hold waste, elephant dung, and pulse residue in 1:1 ratio with equal quantity of water. The biogas generated from different treatments were analysed for CH 4 and CO 2 . The highest CH 4 production was recorded for the treatment combination of pulse residue with cow dung which was on par with cow dung and elephant dung combination, while the highest CO 2 was recorded in the biogas produced from poultry manure and cow dung combination. The hydraulic retention time recorded was lowest for elephant dung and cow dung combination. The highest organic carbon content was recorded in the slurry generated from cow dung alone, which was on par with the combination of goat manure with cowdung. The highest ammoniacal nitrogen content was recorded for biodegradable house hold waste - cow dung combination followed by pulse residue - cow dung combination. The highest total nitrogen content was observed for cow dung - poultry manure combination and cow dung - goat manure combination.157 A pot culture experiment was conducted to find out the manurial value of the slurry obtained from the treatments for biogas production with three replications and six treatments. This experiment was done by irrigating the pots with the slurry obtained from the treatments along with absolute control, as per Package of Practices and Recommendations of KAU (both were irrigated with fresh water) and with fresh undigested cow dung slurry with cowpea (var. Bhagyalakshmy) as test crop. The highest number of pods per plant and the highest yield were obtained from the plants which were irrigated with biogas slurry produced from pulse residue and cow dung combination. After harvest, the highest organic carbon content was noted in soil which was irrigated with biogas slurry produced from elephant dung and cow dung combination. The highest available nitrogen and available phosphorus content was recorded for soil irrigated with slurry produced from cow dung alone and cow dung - pulse residue combination. Available potassium content in soil was highest for in the soil which was irrigated with slurry produced from poultry manure and cowdung combination which was on par with slurry produced from elephant dung- cow dung combination. The plants irrigated with the slurry produced from cow dung-pulse residue combination and cow dung-elephant dung combination had recorded highest uptake of total nitrogen. Plants raised from the seeds obtained from these treatments showed greater shoot length, seedling length and vigour index. However elaborate studies are necessary to monitor the hormones present in different types of slurry generated from different substrates.
Open Access
Silicon, boron and zinc nutrition of bitter gourd (Momordica charantia L.) var. preethi
(Department of plant soil science and agricultural chemistry, Padannakkad, 2015) Mohammed, Shahid Salam C H; KAU; Suresh, P R
The experiment entitled “Silicon, boron and zinc nutrition in bitter gourd (Momordica charantia L.) var.Preethi” was carried out with the objective to standardize the dose and method of application of silicon, boron and zinc red loam soils. The investigation was carried out at College of Agriculture (COA), Padannakkad and RARS farm at Nileswar during April 2014 to August 2014. The whole study consisted of two parts- pot culture and field experiments. The pot culture study was conducted at COA, padanakkad. The experiment was carried out in RBD taking into consideration of varying light intensity at the site of pot culture area. The treatments applied with three levels each of zinc and boron (0.2, 0.4 and 0.6%) respectively and two levels of silicon (20 and 40 ppm) on soil basis. There were eighteen treatment combinations and one control with three replications. The soil taken from the field of RARS, Nileswar and uniformly filled in pots arranged in three blocks and then plants was raised in that. Five seed were sown in each pot then thinned to single plant. Silicon is applied as calcium silicate to soil at the time of planting. Boron and zinc are applied as foliar with borax and zinc sulphate respectively, biomtric yield data were collected. Significant differences among the treatments were observed in the biometrics characteristics of plants and for yield. T14 (B-0.6% foliar + Zn-0.2% foliar + Si-40 ppm in soil) recorded highest fruit length, breadth, weight and vitamin C content. Another experiment with same treatments was also carried in RARS farm, Nileswar in RBD with nineteen treatment and three replications. Three plants were maintained in each pit and each of the plot have four such pits. Majour nutrients viz, N, P, K application and other cultural practices were uniformly followed for all plants as Package of practices, KAU (2011). Method of application and level of application of silicon, boron and zinc were same as that of pot culture experiment. Foliar application are done at 30th , 40th , 60th days after planting. Soil application of silicon at two levels was done at the time of planting. The result of field experiment revealed that, yield and quality parameters differed significantly with the application of varied levels of Si, B and Zn. Highest vitamin C was found in T14 (B-0.6% foliar + Zn-0.2% foliar + Si-40 ppm in soil). It also showed highest fruit 107 length, breadth, weight and yield. While in the case of Fe content of fruits T9(B-0.4% foliar + Zn-0.4% foliar + Si- 20 ppm in soil) recorded highest concentration in fruits. After the harvest, the effect of these treatments on soil nutrient availability was studied. The results showed that available N, P, K, Ca, Mg, S, Si, B and Zn status in treated plot were improved significantly when compared to control. Similarly, leaf nutrient analysis at the time of harvest revealed that N, P, K, Si, B and Zn were showed significant differences among treatments. Both pot culture and field experiment indicated th effect of silicon and boron are more important than zinc in bitter gourd. T14 (B-0.6% foliar + Zn-0.2% foliar + Si-40 ppm in soil) found to be performing well under pot culture and field conditions respectively.
Open Access
Decomposition of leaf litter by oriculture
(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2015) Nithya, Jose; KAU; Sushama, P K
Oriculture involves the use of macrophytophagous oribatid mites to bring about biodegradation of plant litter, converting the same into nutrient rich humus which can be utilized as a bio-fertilizer.In oriculture, the oribatid mite species with a proven role in bio processing of plant litter are mass cultured and released into the soil. Success of oriculture lies in the right choice of oribatid mite species based on the particular type of plant litter. Oriculture can thus be treated as the modern method of agriculture with minimum cost of production and maximum yield in a most suitable ecofriendly atmosphere. So the proposed study entitled “Decomposition of leaf litter by Oriculture” was conducted during the period 2014-2015 to envisage the standardization of the methodology for mass multiplication of selected oribatid mites, and to assess the degrading efficiency of soil dwelling oribatid mites on various types of leaf litter and also to evaluate the manurial value of bio processed litter. Standardization of the methodology for oriculture based on the procedure suggested by Xavier and Haq (2006) was conducted in Completely Randomised Design with six treatments and three replications. For that soil samples were collected from different tree growing areas like cashew, rubber, jack, cocoa, teak and mixed forest plantation. Isolation of mites from soil and litter samples was carried out. It was not possible to extract mites from soil samples but isolation and mass culturing of mites using jack litter was made possible by using Berlese tulgren apparatus. The potential of isolated mites to infest the crop plant okra was studied by releasing a known number of mites by adopting standard procedure. Since the mites being soil habituated, it could not survive on the plant. The isolation of symbiotic microflora associated with mites recorded fungal populations of 3×10-1 cfu/g of sample and bacterial population 11×10-1 cfu /g of sample. Among that most predominant microflora, four bacteria and three fungi were selected for further studies, of which one belonged to Aspergillus sp. and other one was Penicillium sp. Invitro screening of symbiotic microflora for lignin,tannin,and cellulose degrading ability revealed that lignin and tannin degrading microorganisms were present. Antagonistic activity of isolated microflora against the five major soil borne pathogen revealed that the isolate bacteria 8 and fungi 3 can control all the tested one. The experiment to assess the manurial value of decomposed litter was done by factorial CRD with different combinations of two factors, leaf litter of varying C:N ratio and different modes of biotic enrichment (Litter alone, litter+ cow dung , litter+ mites , litter+ cow dung+ mites ) as treatments and three replications. The percentage of litter decomposed was assessed and found that jack litter with the biotic enrichment litter+ mite + cow dung found to be the best combination showing the highest percentage irrespective of the litter type. Maximum percentage of litter decomposed was observed for jack litter with the biotic enrichment, litter+ cowdung+ mite and minimum decomposition rate was for cocoa with biotic enrichment litter alone. Effect of different modes of biotic enrichments on the contents of macro and micro nutrients observed to be highest in the treatment combination litter + cow dung+ mites.Influence of litter types on nutrient content of decomposed litter revealed that highest carbon content (51.26 %) was in cashew litte, N content was in jack litter (3.20 %), P content (0.31 %) was in teak litter and highest K content (0.24%) in cocoa litter. Influence of litter type and biotic enrichment on N, P,K content of the decomposed litter showed that jack litter +cow dung +mites was highest in N content (3.46 %) and teak litter + cow dung +mites was highest in P (0.47 %) and mixed litter + cow dung + mites had highest K(0.21%) content.
Open Access
Production and effective utilization of biogas from fruit waste
(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2015) Aswathy, Gopinadhan; KAU; Sushama, P K
Fruits are highly perishable commodities and generate huge amount of waste.Besides loss of freshfruits,waste is also generated during the processing stage. Fruits and vegetable processing industries generate waste up to the extent of 25-40 per cent of raw materials used. Disposal and proper management of these fruit waste has become a serious problem to agro-entrepreneurs. Biological conversion of biomass to methane has received increased attention during recent years So the proposed study entitled “Production and effective utilization of biogas from fruit waste” was conducted at College of Horticulture to envisages the standardization of biogas production from fruit waste and the effect of biogas slurry on the germination of mango stones. The broad objective was to enable the agro-entrepreneurs to effectively utilize the fruit waste from processing factories. In order to determine the optimum ratio of cow dung and fruit waste for maximum biogas production, the floating drum biogas digesters of 0.5 m3 capacity were used. The experiment was conducted in completely randomized design and consists of six treatments and three replications (T1 : Cow dung alone, T2 : Fruit waste alone, T3 : Cow dung + Fruit waste (1:0.5), T4 : Cow dung + Fruit waste (1:1), T5 : Cow dung + Fruit waste (1:1.5), T6 : Cow dung + Fruit waste (1:2). The results indicated that mixing cow dung and fruit waste in a proportion of 1:1.resulted in the generation of biogas with 65.30 % methane and 32 % carbon dioxide which was closely followed by T5 (Cow dung: fruit waste,1:1 ratio) . Fruit waste alone was loaded to the biogas plants which were found to be comparatively inferior in methane generation. The treatment T5 (Cow dung: fruit waste, 1:1 ratio) also produced the highest volume of gas (0.44 m3/day) within 17 days Hydraulic Retention Time (HRT). The pH of the slurry varied from 6.4-8.0 and EC between 0.52-0.79 and total solids ranged between 2.10-6.55 per cent and organic carbon content to 19.83 to 26.09 %. The highest C/N ratio was in Fruit waste alone (27.19) and lowest in Fruit waste and cow dung 1:1 ratio (9.48). The best combination in view of maximum manurial value was cow dung and fruit waste in 1:2 ratio (2.58 % N, 0.81 % P and 2.23 % K) which was selected for the second experiment. The experiment to evaluate the effect of biogas slurry on germination of mango seed stones was done in CRD consisting of seven treatments and three replications. Two varieties (Moovandan and Bangalora) were made use of. The germination per cent and vigour index was found to be maximum for pre soaking with fruit waste slurry (T7 )which was closely followed by presoaking with cow dung slurry (T5) for both the varieties. After germination the reducing sugar content of mango stones of both the varieties were found to be was found to be increased compared to the initial content. The nutrient uptake for almost all the nutrients was higher with presoaking treatments with the slurry. There was significant decrease in available soil nutrient contents after the experiment as compared to the initial contents in potting mixture used for the study due to crop uptake.
Open Access
Investigations on the efficacy of biochar from tender coconut husk for enhanced crop production
(Department of soil science and agricultural chemistry, College of agriculture, Vellayani, 2015) Mariya Dainy, M S; KAU; Usha, P B
An investigation was carried out at College of Agriculture, Vellayani to characterize biochar from tender coconut husk and to assess its effects on soil properties, growth and yield of yard long bean (Vigna unguiculata subsp. sesquipedalis). The experiment consisted of production and characterization of biochar, laboratory experiments on nutrient sorption- desorption studies, carbon dioxide emission studies and a field experiment. Biochar was produced from tender coconut husk by the process of pyrolysis and it was crushed, sieved and the 2 mm sieved samples were used for further studies. The produced biochar had an alkaline pH (9.13), high CEC (15.26 cmol kg-1) and C: N ratio (68.86). Electrical Conductivity, total C, N, P, K, Ca, Mg and S contents in the prepared biochar were 1.73 dS m-1, 72.3 per cent, 1.05 per cent, 0.38 per cent, 2.27 per cent, 0.40 per cent, 0.20 per cent and 0.27 per cent respectively. The produced biochar recorded very high water holding capacity (226 per cent), low bulk density (0.14 Mg m-3) and high Brunauer Emmett Teller surface area (157.93 m² g-1) A laboratory experiment was conducted to study the desorption and sorption of nutrients like N, P, K, Ca, Mg, S, Fe, Mn, Zn and Cu using biochar. 32.35 per cent NH4+, 75.65 per cent PO42-, 45.14 per cent K+, 46.00 per cent Ca2+, 23.45 per cent Mg2+, 74.38 per cent SO42-, 36.80 per cent Fe2+, 30.20 per cent Mn2+, 26.75 per cent Zn2+ and 26.72 per cent Cu2+ were found to be desorbed from biochar after 7 rinses using de-ionized water in 1:100 ratio. The highest per cent of nutrient desorbed was P (75.65 per cent), followed by S (74.38 per cent) and the lowest per cent of nutrients desorbed were Zn (26.75 per cent) and Cu (26.72 per cent) within 72 hours. Sorption experiments were performed using rinsed biochar at different concentrations of nutrients and at different time intervals in 1:100 ratio. The results of the study indicated that biochar could sorb 100 per cent NH4+, 90.70 per cent PO42-, 92.00 per cent K+, 87.00 per cent Ca2+, 86.15 per cent Mg2+ and 91.82 per cent SO42- when it was equilibrated with 100ppm solutions within 24hours. For micronutrients, when 50 mg l-1 Fe2+, Mn2+, Zn2+ and Cu2+ solutions were given, biochar could sorb 99.67 per cent, 100 per cent, 99.12 per cent and 99.12 per cent respectively. Biochar from tender coconut husk is a good sorber and slow releaser of nutrients. An incubation study was carried out to estimate and study the pattern of carbon dioxide emission by the application of biochar into soil and it was compared with that of common organic amendments viz. FYM and vermicompost. The experiment consisted of 7 treatments with 3 replications and the study revealed that the cumulative amount of carbon dioxide emitted was highest for FYM @ 2 per cent (1014.05 mg CO2 100 g-1) and biochar @ 2 per cent registered an emission of 87.17 mg CO2 100 g-1 after 6months of incubation. There observed 91.40 per cent reduction in CO2 emission when soil was incubated with biochar @ 2 per cent compared to 2 per cent FYM. A field experiment was carried out with biochar and other commonly used organic manures at different doses using yard long bean variety Vellayani Jyothika as the test crop during January 2013 to April 2013, at the Instructional farm, College of Agriculture, Vellayani. Yield (1358 g plant-1) and yield attributes like pod length (54.50 cm), pod girth (3.90 cm), number of pods per plant (51), nutrient uptake and B: C ratio were significantly superior for the treatment T8 which received biochar @ 20 t ha-1 with 2 per cent PGPR and NPK as per POP. Physical properties chemical properties of the soil were significantly improved by the application of biochar @ 30 t ha-1. Biochar application reduced the bulk density, increased water holding capacity, water stable aggregates, pH, Cation Exchange Capacity, organic carbon status and nutrient availability. From the investigations, it can be concluded that application of biochar @ 20 t ha-1 along with 2 per cent PGPR and NPK as per POP which resulted in the yield of 1358 g plant-1 (20.12 t ha-1) can be considered as the economically viable and the best treatment. Biochar from tender coconut husk can be used as a good soil amendment which can improve soil health and enhance crop production.
Open Access
Nutrient dynamics and transformation in aerobic and flooded systems of rice in lateritic soils of kerala
(Department of soil science and agricultural chemistry, College of Horticulture, Vellanikkara, 2015) Geetha, P; KAU; Sureshkumar, P
Field experiments on aerobic and flooded systems of rice were conducted in second crop season with the objectives to study the nutrient dynamics and transformations in these systems in second crop season with rice (variety Jyothi), in farmer’s field, at Nellikkattiri, Thirumittakode panchayat, Palakkad district. The treatments with two doses of fertilizers (as per Package of Practices Recommendations, KAU and based on soil test) and three doses of lime (as per POP, as per ΔpH and as per SMP buffer method) were imposed in plots of 20m2 area in Randomized Block Design with four replications. Under flooded condition, two field experiments were conducted to standardize the method of sampling and analysis for soil test based application of lime and fertilizers. One was based on sampling and soil testing on wet basis keeping the anaerobic environment unchanged, while the other was based on routine sampling and analysis after air drying. Better correlations with respect to available nutrients and plant nutrient content were obtained for wet analysis based recommendation and hence the data from this experiment were considered for comparison of the nutrient dynamics with that of the experiment on aerobic rice. In situ measurement of pH, electrical conductivity and redox potential was done under both systems of rice cultivation. Redox potential was measured from three different depths under flooded system (15, 30 and 45 cm) and from two different depths under aerobic system (30 and 45 cm). The soil and plant samples were collected at three stages viz. at active tillering, panicle initiation and at harvest of the crop. The soil samples collected were analysed for pH, EC, OC available nutrients (P, K, Ca, Mg, S, Fe, Cu, Mn Zn and B), and were also assayed to estimate fractions of soil phosphorus, iron, zinc and boron. The plant samples were analysed for N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu and B. At harvest straw and grain samples were analysed separately. The increase in pH in both systems was in proportion to the quantity of lime applied. Higher rate of increase in pH was observed under aerobic system. Increase in EC was in proportion to the quantity of lime and fertilizers added, and it was more in aerobic system due to less dilution. The redox potential became negative due to reduced environment in flooded system within two weeks of transplanting while it was consistently positive under aerobic system. The organic carbon content was higher under aerobic environment at active tillering and panicle initiation due to quicker decomposition of applied organic matter especially in presence of lime while it was lower under flooded condition initially due to slower rate of decomposition. Available P was highest under flooded system due to release of bound P from Fe and Mn by reduction of these elements to their respective soluble forms. Under aerobic condition, the available P recorded at active tillering and panicle initiation was lower than that of the initial value, due to its precipitation as tri calcium phosphate [Ca3 (PO4)2]. The available K status was higher under aerobic condition throughout the crop growth because of reduced rate of leaching under this environment. The rate of increase in available K was concurrent to the quantity of fertilizer added under both systems of rice cultivation. Highest K content in plant was recorded under aerobic rice system. The highest available Ca was recorded at active tillering and panicle initiation in flooded system of rice cultivation, because of the solubilization of applied lime. At harvest, the available Ca became precipitated as tri calcium phosphate which decreased the availability of both Ca and P under flooded condition. The transformation of tri calcium phosphate to mono calcium phosphate occurred only under aerobic condition during later stages. The highest Mg in plant was recorded in treatment where fertilizer application was done based on soil test under both systems of rice cultivation. The available sulphur status was higher under flooded condition during all the stages of sampling because of the increased solubility of applied factomphos and MgSO4. The status of available Fe was higher under flooded environment because of the reduction of Fe3+ to soluble Fe2+, while the available Fe status was found to decrease under aerobic condition due to oxidation of Fe2+ to insoluble Fe3+. The available Mn status under flooded environment decreased when compared to that of aerobic condition because of enhanced absorption by rice. The lower status of available Zn under aerobic condition resulted from more absorption of Zn by the crop, because of decreased competition from cations such as Fe3+ and Mn4+ under aerobic condition. The available boron status and boron content in plant was high under flooded condition because of the enhanced solubility of applied borax. Ultimately, aerobic rice recorded significantly higher grain and straw yield (6.23 t ha-1 and 6.35 t ha-1 respectively) than that under flooded system (5.12 t ha-1 and 5.52 t ha-1 respectively). The treatment with fertilizer application based on soil test and with lime as per SMP buffer method under aerobic situation recorded significantly higher grain yield of 6.8 t ha-1 because of balanced nutrition in this treatment combination. Higher root CEC, root mass, shoot mass root volume and root length were recorded under aerobic system. The decline in productive tillers during active growth phase was observed under flooded environment. Well developed aerenchymatic tissue in the roots was observed only under flooded environment. The water requirement was reduced by 57 % in aerobic rice, than that in flooded rice.
Open Access
Heavy metal contamination of laterites by accumulation of solid wastes
(Department of soil science and agricultural chemistry, College of horticulture, Vellanikkara, 2015) Divya Vijayan, V; KAU; Sushama, P K
A heavy metal is defined as a metal that has the atomic number and specific gravity greater than 20 and 5 Mg m-3, respectively. Heavy metals occur naturally in the soil environment from the weathering of parent materials and also as contaminants at the waste disposing sites. Though, the soil acts as a sink for the majority of heavy metals, the excess uptake of any one of them may limit the plant growth. In this background, the research work entitled “heavy metal contamination of laterites by accumulation of solid wastes” was undertaken during the period 2010-2014. The project aims to investigate the extent of distribution of heavy metals (As, Cd, Cr, Pb, Hg and Co) in waste dumping sites of laterite as influenced by soil and climatic conditions using geostatistical technique, to correlate the activity of major soil enzymes with the contents of heavy metals, to explore the potential of phytoremediation as well as aerobic and anaerobic methods of composting for the removal of heavy metals in solid waste and to evaluate the performance of amaranthus under different decontaminated methods adopted. In order to attain the objectives, four experiments were conducted. The effect of soil and climatic factors on heavy metal accumulation was examined with the collection of soil samples at quarterly intervals for a period of one year from two different waste disposal sites located at Laloor and Kalamassery. For the study on phytoremediation, the crops, vetiver, marigold and sunflower were experimented. Both the aerobic and anaerobic methods of composting were tried for the removal of heavy metals in another set of experiment. A pot culture study was also conducted to assess the growth of amaranthus under different decontaminated conditions. The salient findings are summarized as follows: The percentage distribution of Pb, Ni, Co, Cr and Hg at the different sites of Kalamassery revealed that Cr had the highest distribution followed by others. At Laloor, Pb was found to be dominant for the major dumping sites, whereas Cr at the non dumping site. The geo accumulation index for Hg was recorded as above one for all sites at Kalamassery. The average contents (mg kg-1) of Pb, Co, Ni, Hg and Cr was 15.58, 6.06, 43.18, 0.56, 107.9 at Kalamassery and 82.84, 7.79, 35.54, 0.42 and115.67 at Laloor, respectively. Heavy metal contents were found to be higher during summer than rainy season except for Cr and Cd. In general, soil enzyme activities were higher during quarter II of the sampling period. There was a positive correlation between Fe and urease (0.391*) and Pb and phosphatase (0.350*). The phytoremediation study with the three different crops (sunflower, marigold and vetiver) proved vetiver as a good phytostabilizer compared to others. Vetiver was found to be a translocator of Cr, since Ni, Pb, Co and Hg were mostly stabilized in the root. Marigold translocated all these heavy metals from soil except Co, and sunflower translocated Co, Ni and Cr except Pb. Bioconcentration factor (the heavy metal concentration in the plant/ the heavy metal concentration in the soil) was higher for vetiver compared to sunflower and marigold. Vetiver removed the heavy metals from the waste material in the order Cr>Ni> Co> Pb. Compared to aerobic composting, the anaerobic method proved to be better for the removal of heavy metals from the waste material collected from Laloor. The comparative performance of amaranthus grown in soil under different methods adopted for reducing heavy metal contamination showed that the yield was found to be the highest in the treatment with aerobic compost. The lowest yield was reported for amaranthus grown with phytoremediated material, followed by absolute control. The uptake of major nutrients also followed the same trend as yield. The heavy metal content was higher in the shoots of amaranthus grown with waste material and the accumulation followed the order Cr>Pb>Ni>Co>Hg. In all the treatments under study, the presence of Cr was more dominant in the post harvest soil compared to other heavy metals.
Open Access
Assessment and management of micronutrient deficiencies in Onattukara
(College of Agriculture, Vellayani, 2015) Mini, V; KAU; Usha, Mathew
A study on “Assessment and management of micronutrient deficiencies in Onattukara” was undertaken with an objective to assess the available micronutrient status of the Onattukara region to develop a multi micronutrient mixture for balanced crop nutrition and to evaluate the effect of multi micronutrient mixture on growth and yield of okra. Two hundred georeferenced soil samples were drawn at random from twenty soil series of the Onattukara region representing different crop production systems and analysed for 13 soil fertility parameters. The results of the analysis of various soil parameters were integrated in GIS for the preparation of thematic maps. The overall fertility status of this region indicated that the soil was very strongly acidic with high level of phosphorus, low oxidisable organic carbon and available potassium and wide spread deficiencies of calcium, magnesium, boron and zinc. Observational trials were conducted at 18 different locations to assess the response of the okra crop to adhoc recommendations by KAU for micronutrients. Micronutrient application increased the yield up to eighty percent in these trials. Micronutrient fertilizer requirement was computed based on the available micronutrient status of the region and crop requirement. A multi micronutrient mixture having a composition of Zn (9.5%) + B (2.6%) +Cu (1.2%) +Mg (2.4%) +N (0.46%) @ 20kg ha-1 was developed and the effect of multi micronutrient mixture was assessed in the field experiments using okra variety Varsha Uphar as the test crop in two seasons during September- December in 2013 and February -May in 2014. The field experiment consisted of nine treatments and the treatments were T1 (Absolute control), T2 (Package of Practices (POP) ), T3 (Soil test based POP and secondary nutrients), T4 (Treatment 3 + computed dose of micronutrients mixture), T5 (Treatment 3 + 25% less of computed dose of micronutrients mixture),T6 (Treatment 3+ 25% more of computed dose of micronutrients mixture), T7 (Treatment 3+ foliar application of 0.5% solution of computed dose of micronutrients mixture), T8 (Treatment 3+ foliar application of 0.5% solution of 25% less of computed dose of micronutrients mixture) and T9 (Treatment 3 + foliar application of 0.5% solution of 25% more of computed dose of micronutrients mixture). Growth, yield and quality of okra increased significantly due to multi micronutrient mixture. Application of soil test based NPK and secondary nutrients + foliar application of 0.5 per cent solution of computed dose of micronutrient mixture @ 5 kg ha-1 in two splits at 15 DAS and 35 DAS (T7) yielded significantly higher (11.3 tha-1) over rest of the treatments. T7 recorded 80 per cent more yield than T3, which was the soil test based package of practices (POP) and secondary nutrients and more than double the yield of POP. Soil application of this mixture @ 20kg ha-1 (T4) was also significantly superior to the POP recommendations. Soil status of micronutrients in the experiment site before the experiment was Zn (0.27 mg kg-1), Cu (0.21 mg kg-1) and B (0.17 mg kg-1). After two consecutive application of multi micronutrient mixture, the soil status of Zn, Cu and B were in the range of 0.62 to 1.58 mg kg-1, 0.74 to 0.99 mg kg-1 and 0.19 to 0.31 mg kg-1 respectively. Even after continuous application of micronutrients for two seasons the critical status was not attained for Cu and B in soil. So application of micronutrient fertilizers customized for agro ecological units and crops ensures increased yield and sustain soil health. In general the highest nutrient content and uptake in shoot and fruit were recorded by T7. The highest B: C ratio of 3.02 was also recorded by T7. From the investigation it can be concluded that foliar application of micronutrient mixture @ 5kg ha-1 in two splits at 15 DAS and 35 DAS was superior to soil application with respect to yield, quality and B: C ratio. The study revealed that micronutrient deficiency is one of the yield barriers which can be broken down by including micronutrient fertilizers in the nutrient schedule of crops.
Open Access
Management of calcium, magnesium, sulphur and boron in tc banana (Musa spp.) var. nendran
(College of Agriculture, Padannakkad, 2015) Neethu, Prabhakar; KAU; Suresh, P R
The experiment entitled “Management of calcium, magnesium, sulphur and boron in TC banana (Musa spp.) var. Nendran” was carried out with the objective to study the effect of soil application of calcium, magnesium, sulphur and foliar application of boron on hardening of tissue culture (TC) plants and the application of these nutrients in the field. The investigations were carried out at College of Agriculture (COA), Padannakkad and RARS farm at Nileshwar during December 2013 to January 2015. The whole study consisted of two parts– hardening studies and field experiment. The hardening studies were conducted in the mist chamber at COA, Padannakkad with TC banana plants of uniform age and size derived from same culture. The experiment was carried out in CRD with two levels each of calcium (75 and 150 ppm), magnesium (25 and 50 ppm), sulphur (25 and 50 ppm) and boron (0.25 and 0.5 %). There were sixteen treatment combinations and one control with three replications. Four plants were maintained in each of the replications. The potting mixture was prepared uniformly and then it was fortified using the various treatment combinations of calcium, magnesium, sulphur and the plants were raised in polybags for a period of two months. Boron application in the form of foliar spray at two levels of concentration was carried out immediately after planting and one month after planting. Significant differences among the treatments were observed in the biometric characteristics of the plants. T10 (150 ppm Ca, 25 ppm Mg, 25 ppm S and 0.5 % B) recorded maximum number of leaves, leaf length, leaf breadth and plant height. These two hundred and four hardened tissue culture banana plants were planted at RARS farm, Nileshwar in RBD with seventeen treatments and three replications. Four plants were maintained in each plot. Major nutrients viz. N, P, K application and other cultural practices were uniformly followed for all plants as per POP, KAU (2011). The treatments consisted of soil application of two levels of calcium (75 and 150 g Ca/plant), magnesium (25 and 50 g/plant) and sulphur (25 and 50 g/plant) at second and fourth month after planting along with two levels of boron (0.25 and 0.5 %) foliar sprays at first, second, fourth month after planting and one spray after bunch emergence. Observations of vegetative characters were taken at the time of bunch emergence. The results of the field experiment revealed that among the vegetative characters, number of leaves showed significant differences among the treatment. Highest leaf number and plant height were found in T12 whereas pseudostem girth and number of suckers produced were highest in T3. Among the yield characteristics bunch weight, number of hands, number of fingers, average weight of fingers and average number of suckers showed significant difference. The highest bunch weight and number of fingers were recorded in T4 (75 g Ca + 25 g Mg + 50 g S + 0.5% B) with 12.97 kg as against 10.34 kg in control whereas number of hands was highest in T11. Among the finger characteristics, average weight of finger was highest in T10, length and girth in T3 and T5 respectively. T3 produced maximum number of suckers at the time of harvest. The time span taken from planting to bunch emergence and harvest were non significant. Disease (sigatoka leaf spot) incidence eventhough non significant, compared to control plots the treated plots registered lower incidence. Fruit characteristics like TSS, titrable acidity, vitamin C content, reducing sugar content and pulp to peel ratio were studied. Of these, titrable acidity, vitamin C content, reducing sugar content and pulp to peel ratio showed significant differences among the treatments. Reducing sugar content and pulp to peel ratio of all the treatments were found to be superior to the control. Among the treatments, highest vitamin C content was found in T5. Average titrable acidity was found to be lowest in T2 and highest was in control. Maximum TSS content and reducing sugar percentage was recorded in T6. Among the treatments, lowest pulp peel ratio was in control and highest ratio of was observed in T16. After the harvest, the effect of these treatments on soil nutrient availability was studied. The results showed that EC, P, Cu and Zn status were significant. Similarly, leaf nutrient analysis at the time of harvest revealed that Ca, Mg, S, B, Fe and Mn showed significant differences among the treatments. Both the hardening studies and field experiment indicated the beneficial effect of secondary nutrients and boron on TC banana. T10 (150 ppm Ca, 25 ppm Mg, 25 ppm S and 0.5% B) and T4 (75 g Ca + 25 g Mg + 50 g S + 0.5% B) were found to be performing well under hardening and field conditions, respectively. Benefit cost ratio of the best treatment (T4) extrapolated from twelve plants is found to be 2.85 (@ Rs 35/kg of fruit). So this shows that the treatment is promising higher returns to the farmers.

Kerala Agricultural University, Thrissur

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