1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Balanced N-ary designs with equal or unequal block size & equal or unequal replications(Department of Statistics, College of Veterinary,Mannuthy, 1981) Sujatha, K S; Surendran, P UTocher (1952) introduced n-ary designs as generalization of balanced incomplete block designs. But the properties of the parameters of the design have not been discussed so far. We have shown that some important properties of the balanced incomplete block binary design are also true in the case of balanced n-ary symmetrical proper equireplicate designs. That is if h =∑jnij2 , λ=∑jnijnpj; in a proper equireplicate balanced design then (i) h > λ (ii) b ≥ v (iii) rk = h+(v-1) λ Among the methods block section, block intersection, complementation and inversion considered by us for the construction of designs the method of complementation is only found fruitful for the construction of proper equireplicate balanced designs. There are situations like comparison of new varieties of seeds of which are in short supply where equal replication of treatments is not possible. There may also be contexts in which the available few animals cannot be used completely for the experiment using conventional designs. For such circumstances we have proposed a systematic method of construction of balanced n-ary designs with equal or unequal replications and equal or unequal block sizes. The method of Kronecker product has been formally introduced to the literature for the construction of proper equireplicate balanced n-ary designs and the methods is contained in the following results. If N1 and N2 are two BIB designs with parameters v, b1, r1, k1, λ1 and v, b2, r2, k2, λ2 respectively, for positive integral values of a1 and a2, a1E(1,b2)xN1+a2N2xE(1,b1) is in general a proper equireplicate n-ary design provided a1+a2+1= n. If N1 and N2 are two balanced proper equireplicate n1-ary and n2-ary designs in v treatments with b1,b2 blocks respectively, for positive integers a1 and a2, a1E(1,b2)xN1+a2N2xE(1, b1)is a n-ary balanced equireplicate proper design with b1b2 blocks where n=a1 (n1-1)+a2(n2-1)+1.Item Crop weather relations on yield, quality and weed dynamics of kiriyath(andrographis paniculata(burm.f.) wall.ex nees.)(Department of Agronomy College of Horticulture, Vellanikkara, 2018) Sreethu, M J; Sindhu, P VItem Enhancing fruit set and yield of tomato (solanum lycopersicum L.) in polyhouse using artificial pollination and growth regulators(Department of Vegetable Science, College of Agriculture , Vellayani, 2018) Gayathri, G; Rafeekher, MItem Management of soil salinity with calcium salts in rice-prawn farming system in pokkali lands(Department of Soil Science and Agricultural Chemistry College of Horticulture, Vellanikkara, 2018) Divya, P V; Sreelatha, A KPokkali is the unique system of rice cultivation in the water-logged coastal saline acid soils of Kerala. These are tidal wetlands characterized by multi stressed conditions such as acidity, salinity and waterlogging. Pokkali soils are the major salt affected soils in Kerala. Plant growth is affected by salinity at all stages of development resulting in reduced grain yield, dry matter production and total decrease in productivity. Excess sodium present in the saline environment creates adverse conditions for plant growth. High salinity in the root zone results in osmotic imbalance and ionic toxicity and thereby modifies nutritional status in soil and plant. In this context, the present study entitled “Management of soil salinity with calcium salts in rice–prawn farming system in Pokkali lands”, was conducted with the following objectives (i) to manage the soil salinity by application of calcium salts in pokkali lands (ii) to assess the effect of calcium salts on the growth and nutrition of rice, yield of prawn and soil properties. The experiment was conducted in the Thathapilli padasekharam (10º12’N, 76º26’ E) of Kottuvally Panchayath in Ernakulam district, during June 2017 to April 2018. The experiment was laid out in randomized block design with six treatments and four replications having plot size of 100 m². The treatments consisted of absolute control, calcium nitrate, calcium chloride, calcium sulphate, rock phosphate and dolomite at the rate of 45, 30, 34, 27 and 25 kg per plot so as to adjust the ratio of 1:5 for Na : Ca in the exchange complex on the basis of content of Na and Ca in soils. The Ca salts were applied before the rice crop only. Rice variety, Vyttila 6 was raised in the first crop season. Soil samples were collected from the treatment plots during three stages; before the sowing of crop, after the harvest of rice and after the harvest of prawn and analyzed for various physical (soil texture, bulk density), chemical (pH, EC, organic carbon, available N, P, K, Ca, Mg, S, Fe, Cu, Mn, Zn, B and exchangeable Na and Al) and biological parameters (microbial biomass carbon). Plant samples were collected at the time of harvest and analyzed for N, P, K, Ca, Mg and Na separately for shoot and root so as to assess the source sink relationship. Initial soil analysis revealed that texture of soil was sandy loam with a bulk density of 1.25 Mg m־³. Initial soil pH was 6.74 and electrical conductivity was 1.51 dSm¹־. Soil was deficient in available N, Ca, Mg and Cu and all other nutrients were in sufficiency level. Data on analysis of soil samples after the harvest of rice revealed that, all the treatments showed a superiority over control with respect to chemical parameters and biological parameter. The EC values ranged from 1.59 dSm־¹ to 1.75 dSm־¹. Exchangeable Na and Al content were highest in control. Among the different treatments, calcium nitrate registered peak values of organic carbon and available nutrients especially nitrogen and it reduced the available Fe content to an extent. Application of calcium nitrate significantly increased the grain yield (3300 kg ha־¹) and dry matter content and plant nutrient uptake. Increased shoot and root N content was also recorded and increment was reflected in the case of other plant nutrients also. Consequent reduction in the shoot Na content was observed as a result of reduced salinity. Highest Ca:Mg and K:Na ratio observed in plant samples of calcium nitrate treatment revealed better plant survival rate under salt stress. Next to calcium nitrate treatment, calcium chloride and dolomite treatments recorded higher in grain yield of 2192 kg ha־¹ and 2098 kg ha־¹ respectively and also the nutrient uptake. Soil analysis after the harvest of prawn recorded an increase in available major and secondary nutrients and reduced the Fe and Mn content in all the treatment with slight variation from control. Yield of prawn was highest in calcium treated plots as a whole than control plot and these variations in the productivity was a result of calcium salt treatments during rice cultivation and its residual effect retained in soil. Thus it can be concluded that application of calcium salts in pokkali soils increased the yield of rice and prawns, improved the soil properties and nutrient uptake by plants. Increase in grain yield was higher in calcium nitrate followed by calcium chloride and dolomite treatments. The highest B:C ratio was recorded in dolomite treatment because of the less input cost.Item Assessment of 'blue carbon' in sediment of Indian mangrove (Avicennia officinalis) in selected locations of Vembanad lake ecosystem in Kerala(Academy of Climate Change Education and Research, Vellanikkara, 2018) Aarathy, G S; Prema, DThe present investigation, focused on the estimation of the sediment pool of the blue carbon stocks of the mangrove species Avicennia officinalis (Indian Mangrove) in selected locations of Vembanad lake. Sediment core samples were collected in post monsoon (October – November 2017) and pre monsoon (February – March 2018). The treatments included ‘aged’, ‘recent’, ‘healthy’ and ‘degraded’ mangroves of the selected species and ‘control’ without mangroves. Sediment core samples up to 30 cm depth with 10 cm interval were subjected to standard laboratory and statistical analytical procedures. The cumulative stock of blue carbon in sediment ranged from 6.00 to 139.96 Mg ha -1 in post monsoon and 2.00 to 84.58 Mg ha -1 in pre monsoon. The treatments differed significantly in the cumulative stock of blue carbon in sedimen (p < 0.05), highest seen in ‘healthy’ at 0-30 cm depth in both seasons. Highly significant difference was observed between ‘healthy’ and ‘degraded’, ‘healthy’ having more stock in both seasons. These two treatments differed significantly for layer wise blue carbon in sediment also in both seasons, higher content being seen in ‘healthy’ and there was no significant variation among depths. The range of layer wise blue carbon in sediment, considering all treatments was 0.06 to 0.56 g cm-3 in post monsoon and 0.02 to 0.35 g cm-3 in pre monsoon. Significant difference among treatments was observed at 0-10 cm depth for layer wise blue carbon in two seasons together, and no significant variation was found in sub surface (10-20 cm and 20-30 cm) depth. Spatial maps were prepared for the cumulative stock of blue carbon and layer wise blue carbon in sediment during post monsoon and pre monsoon seasons. The cumulative stock and layer wise blue carbon were higher in post monsoon. Depth wise increase was seen in layer wise blue carbon in post monsoon, though they were not statistically significant. Layer wise blue carbon was significantly correlated with total organic carbon and organic matter (p < 0.01) positively and with C/N ratio in the sediment (p < 0.05). The study suggests total organic carbon and C/N ratio as possible predictive indicators of blue carbon in sediment, with further investigation.Item Efficiency of thiobencarb in dry sown rice(Department of Agronomy, College of Horticulture, Vellanikkara, 1987) Jayasree, P K; Abraham, C TA field experiment was conducted at the Agricultural Research Station, Mannuthy of Kerala Agricultural University during the first crop season of 1986 to find out the best time and method of application of thiobencarb in dry sown rice. The treatments included combinations of six time and two method of applications and two controls (un weeded and hand weeded), laid out in RBD with three replications. The results showed that the count, dry matter production and nutrient removal of weeds were appreciably reduced by the weed control treatments, particularly by the spray applications at 6 and 9 days after sowing. Effective control of the weeds during the critical stages of the crop was obtained for the spray treatment. , while the new flushes of weeds after each hand weeding posed some competition in the hand weeded plot. The weed control efficiency was highest during the critical stages for the spray applications at 6 and 9 days after sowing, even higher than that of hand weeding. The herbicide did not produce any phytotoxicity symptoms on the crop. Tiller production was found to be adversely effected by weed competitions whereas the crop plants tended to grow taller with increased weed density. A significant negative correlation was found to exit between the crop and weed dry matter productions. The spray treatments at 6 and 9 days after sowing produced higher crop dry matter and resulted in maximum uptake of nutrients during the critical stages. The spray applications at 6 and 9 days after sowing gave significantly higher values of the yield attributes viz., the productive tillers per hill, length of panicle and number of grains per panicle, resulting in higher grain yields on per with the hand weeding. These treatments recorded higher straw yields also. The weed index values were lower for 6 and 9 days treatments after sowing. In terms of return per rupee invested, the spray application of herbicide at 6 days after sowing was the best.