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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Bioefficacy and soil health impact of flucetosulfuron in wet seeded rice (Oryza sativa L.)(Department of Agronomy, College of Agriculture, Vellayani, 2018) Arya, S R; KAU; Elizabeth, K SyriacThe investigation entitled "Bioefficacy and soil health impact of flucetosulfuron in wet seeded rice (Oryza sativa L.) was carried out at College of Agriculture, Vellayani, Thiruvananthapuram during the period of 2015-2018. The objectives were to evaluate the bioefficacy of flucetosulfuron in wet seeded rice; to assess its impact on soil health by determining the microbial count, earthworm population, enzyme status and herbicide residue in soil through bioassay using indicator plant as well as to assess the weed seed bank. It was also envisaged to study the in vitro sensitivity of biofertilizer organisms and biocontrol agents to flucetosulfuron. Field experiment was conducted during the I and II crop seasons of 2016- ’17, in a farmer’s field in Kalliyoor Panchayat, Nemom block, Thiruvananthapuram district, Kerala, with 12 treatments replicated thrice in Randomized Block Design. The treatments were: T1 : Flucetosulfuron @ 20 g ha-1 at 2-3 DAS, T2 : Flucetosulfuron @ 25 g ha-1 at 2-3 DAS, T3 : Flucetosulfuron @ 30 g ha-1 at 2-3 DAS, T4 : Flucetosulfuron @ 20 g ha-1 at 10-12 DAS, T5 : Flucetosulfuron @ 25 g ha-1 at 10-12 DAS, T6 : Flucetosulfuron @ 30 g ha-1 at 10-12 DAS, T7 : Flucetosulfuron @ 20 g ha-1 at 18-20 DAS , T8 : Flucetosulfuron @ 25 g ha-1 at 18- 20 DAS , T9 : Flucetosulfuron @ 30 g ha-1 at18-20 DAS, T10: Bispyribac sodium @ 25 g ha-1 at 15 DAS, T11: Hand weeding at 20 and 40 DAS and T12 : Weedy check. The short duration variety Kanchana was used for the trial. The weed flora in the experimental field comprised of four species of grasses, six species of broad leaved weeds and three species of sedges. Based on density and dry weight, sedges were the predominant group in the experimental field followed by broad leaved weeds and grasses. Application of flucetosulfuron @ 20, 25 and 30g ha-1 at 10-12 and 18-20 DAS (T4, T5, T6, T7, T8 and T9) recorded lower total weed density, total weed dry weight and nutrient removal by weeds and higher total weed control efficiency and were on par with the hand weeding treatment (T11). Yield reduction due to weeds was found to be 52.33 and 55.61 per cent during the I and II crop seasons respectively. The highest grain yield was recorded by the application of flucetosulfuron @ 25 g ha-1 at 10-12 DAS (T5) and flucetosulfuron @ 20 g ha-1 at 10-12 DAS (T4) during the first and second crop seasons respectively. The same trend was observed in the case of dry matter production also. Pooled analysis of the grain yield for the two seasons indicated the superiority of T5 which recorded the highest grain yield of 8.33 t ha-1. This treatment was on par with the other levels of flucetosulfuron viz., 20 and 30 g ha-1 at 10-12 DAS (T4 and T6) and hand weeding treatment (T11). Higher yield attributes, harvest index and nutrient uptake were also recorded for these treatments. However, net income and B:C ratio were significantly lower for hand weeding treatment. Herbicide application did not cause any significant inhibitory effect on the earthworm population and spider count. Application of herbicides increased the microbial population in herbicide treated plots. Flucetosulfuron, at the tested doses (20, 25 and 30 g ha-1) and time of application (2-3, 10-12 and 18-20 DAS), did not show any adverse impact on the activity of soil enzymes (dehydrogenase, acid phosphatase and urease) and soil organic carbon status. To identify the most suitable indicator plant for assessing flucetosulfuron residue in soil, four separate pot culture experiments were conducted using barnyard millet, cucumber, sunflower and maize. Sunflower was identified as the most sensitive indicator plant and shoot length of sunflower was adjudged as the best parameter to assess the flucetosulfuron residue in soil. Bioassay after each field experiment using sunflower revealed that there was no residual toxicity of flucetosulfuron in the post experiment soil. Pot culture experiments were carried out before and after each field experiment, to study the weed seed bank dynamics. Results revealed that non- herbicidal plots recorded higher weed count compared to herbicide applied plots. In all the herbicide treated plots, effective reduction in weed seed bank could be obtained irrespective of the dose of the herbicide. Regarding the time of application, application of flucetosulfuron at 10-12 and 18-20 DAS caused significant depletion of weed seed bank during both the seasons compared to its application at 2-3 DAS. In vitro sensitivity of biofertilizer organisms viz., Azospirillum lipoferum, Azotobacter chroococcum, Bacillus megaterium and Frateuria aurantia to flucetosulfuron indicated that growth of none of the organisms were significantly inhibited by the tested doses of flucetosulfuron. Similarly, in vitro sensitivity to biocontrol agent Trichoderma viride revealed that, at all the tested concentrations of flucetosulfuron, it showed a colony diameter of 9 mm uniformly with zero per cent inhibition indicating the compatibility of the herbicide. The compatibility studies with Pseudomonas fluorescens also revealed the safety of the herbicide. The present study revealed that application of flucetosulfuron @ 20, 25 and 30 g ha-1 at 10-12 DAS was very effective in controlling the weeds and recorded significantly higher grain yield and monetary benefits in wet seeded rice. Application of flucetosulfuron @ 20, 25 and 30 g ha-1 at 2-3/10-12/18-20 DAS had no adverse impact on soil health and was found compatible with the tested biofertilizer organisms (Azospirillum lipoferum, Azotobacter chroococcum, Bacillus megaterium and Frateuria aurantia) and biocontrol agents (Trichoderma viride and Pseudomonas fluorescens).ThesisItem Open Access Herbicide mixtures for weed management(Department of Agronomy,College of Agriculture, Vellayani, 2016) Sheeja, K Raj; KAU; Elizabeth, K SyriacThe experiment entitled "Herbicide mixtures for weed management in direct seeded puddled rice Oryza saliva L." was carried out at College of Agriculture, Vellayani, during the period from 2013 - 2016, to assess the bioefficacy of two post emergence herbicide mixtures viz., bispyribac sodium + metamifop and penoxsulam + cyhalofop butyl in direct seeded rice; to study the residual effect in soil; to investigate the impact on microbial and earth worm population, soil enzyme activity and weed seed bank and also to assess the in vitro sensitivity to soil borne pathogen, Rhizoctonia solani, bio control agents and bio fertilizer organisms. Field experiment was undertaken during first and second crop seasons of 2014-15 at Nemom block at farmer's field. The experiment was laid out in RED with 12 treatments and three replications. Bispyribac sodium + metamifop @ 60, 70, 80 and 90 g ha"*,penoxsulam + cyhalofop butyl @ 120, 125, 130 and 135 g ha"*, bispyribac sodium @ 25 g ha"', penoxsulam @ 22.5 g ha"', hand weeding twice and weedy check constituted the treatments. The higher three tested doses of penoxsulam + cyhalofop butyl v/z.,125, 130 and 135 g ha ' and the highest tested dose of bispyribac sodium + metamifop viz., 90 g ha"' were better than other weed management treatments in improving the growth and yield attributes of rice. Pooled analysis indicated the superiority of penoxsulam + cyhalofop butyl @ 135 g ha"' which recorded the highest grain yield (8463 kg ha ' ) and it was statistically on par with its lower doses (130 and 125 g ha*'). Straw yield was not significantly influenced by the weed control treatments. Penoxsulam + c^lofop butyl @ 135 g ha"' recorded the highest net returns (93744 ha *) and B: C ratio (2.43), which was on par with its lower dose (130 g ha"'). Penoxsulam + cyhalofop butyl @ 135 g ha"' was more effective in reducing the total density of weeds. With regard to the control of sedges and BLW, penoxsulam + cyhalofop butyl was more effective, but with respect to grasses, both the herbicide mixtures were more or less similar in effectiveness. Penoxsulam + cyhalofop butyl @ 135 and 136 registered higher weed control efficiency and lower weed index than other treatments. Uncontrolled weed growth caused a yield reduction of 50.38 per cent. Herbicide treatments significantly reduced the nutrient uptake by weeds and enhanced the nutrient uptake by crop over weedy check. The higher doses of penoxsulam + cyhalofop butyl (125,130 and 135 g ha"') and bispyribac sodium + metamifop (70, 80 and 90 g ha*') were more effective in maintaining higher nutrient content in soil. Dynamics of soil microbial population, earthworm population, soil enzyme status and organic carbon content of soil consequent to the application of herbicide mixtures revealed that, both penoxsulam + cyhalofop butyl and bispyribac sodium + metamifop at their tested doses did not have any inhibitory effect. Results of screening trial revealed that maize was the most sensitive indicator plant for both the herbicide mixtures. Dry weight and fresh weight of maize shoot were adjudged as the best parameters for assessing the residual effect of bispyribac sodium + metamifop and penoxsulam + c>^Iofop butyl in soil respectively. Pot culture bioassay studies revealed that the tested herbicide mixtures and their doses did not have any residual effect. In vitro sensitivity studies of bispyribac sodium + metamifop and penoxsulam + cyhalofop butyl to Rhizoctonia solani pointed out that both the herbicide mixtures inhibit the growth of Rhizoctonia solani. Studies on the in vitro effect of herbicide mixtures to Trichoderma viride indicated that bispyribac sodium + metamifop was safe to the fungus, whereas penoxsulam + cyhalofop butyl was moderately toxic. Compatibility studies revealed that both the herbicide mixtures were highly compatible with Psetidomonas fluorescenSy Azospirillum lipoferum and Azotobacter chroococciim. Weed seed bank assay results indicated the effectiveness of the higher doses of penoxsulam + cylialofop butyl (135, 130 and 125 g ha'') in depleting the seed bank compared to other treatments. The present study revealed the superiority of heibicide mixtures over individual herbicides in the management of weeds in wet seeded rice. Application of penoxsulam + cyhalofop butyl @ 135 or 130 g ha*', at 15 DAS could be adjudged as the most economic and ecofriendly weed management practice for wet seeded rice as evidenced by high weed control efficiency, net returns and B: C ratio; environmental safety, high inhibitory effect to Rhizoctonia solani and good compatibility with bio control agents and bio fertilizer organisms.ThesisItem Open Access Management of blood grass(isachne miliacea roth ex roem et schult) in wetland rice ecosystem(Department of Agronomy, College of Agriculture, Vellayani, 2018) Renjan, B; KAU; Sansamma GeorgeThe study entitled “Management of blood grass (Isachne miliacea Roth ex Roem et Schult) in wetland rice ecosystem” was carried out at College of Agriculture, Vellayani during the period 2016 - 2018. The objectives were to study the eco-biology and habitat affinity of blood grass, to develop an effective strategy for managing the weed, to study the influence of the management practices on weed dynamics, to work out the economics of the weed management practices and also to assess the impact of the herbicides on the soil microorganisms. The weed biology was studied by observing sample plants for a period of one year. The results revealed that blood grass which propagated through both seeds and rooted stem bits flourished in the rice field all throughout the year. The seeds showed no dormancy and could germinate soon after shedding. However direct sunlight was found essential for germination of the weed seeds. The stored seeds retained > 80 per cent viability upto six months and after that there was a sharp decline in germination percentage. Effect of water regime and soil depth on weed propagation was assessed by conducting two separate lab studies by subjecting the seeds and stem cuttings to varying soil and water depth. The design was CRD and there were 5 x5 treatments (Factor I. Water depth (W): 0, 2.5, 5.0, 7.5, 10.0 cm and Factor II. Soil depth (S): 0, 2.5, 5.0 ,7.5, 10.0 cm ) and three replications. From the results, it was inferred that soil depth was the major factor that determined the germination and establishment of blood grass which emphasized the significance of land preparation in managing blood grass. Plant and soil samples from heavily infested rice field sites in four agro ecological units (AEU 10-North central laterite; AEU 4- Kuttanad; AEU 9- South central laterite; AEU 8- Southern laterite) were collected and analysed and correlated with weed dry weight to assess the habitat affinity of the weed. The results indicated that the biomass production of blood grass has significant positive correlation with soil organic carbon and available nitrogen while EC was negatively correlated. Water level also had significant negative correlation with plant dry weight. The field experiments to develop an effective strategy for managing the weed were conducted during the first and second crop seasons of 2016 at the State seed farm, Kottarakkara, Kerala. the initial infestation intensity of blood grass was 84 per cent. The experiment was laid out in split plot design with three replications and the crop variety used was Sreyas released from Rice Research station Moncombu, Kerala. Combinations of tillage (P) and water regimes (W) were the main plot treatments and weed management practices (M) were the subplot treatments. The tillage practices included were: P1- intensive tillage (three ploughings fb puddling) and P2 farmers‟ practice (two ploughings fb puddling). The water regimes tried were W1-continuous deep water ponding i.e., > 7.5 cm from 7 days after transplanting (DAT) till grain filling stage, W2- >7.5 cm water from 7 DAT till panicle initiation stage and W 3- maintaining about 5cm water level with intermittent drainage (KAU, 2011). The weed management practices in the subplots were M1 - oxyflourfen @ 0.15 kg ha-1 fb one hand weeding (HW), M2 - azimsulfuron @ 35 g ha-1 , M3- (bispyribac sodium + metamifop) 70 g ha-1 , M4- fenoxaprop- p-ethyl @ 60 g ha-1 , M5- hand weeding twice at 20 and 40 DAT and M6 - unweeded control. Oxyflourfen was applied as pre- plant three days before transplanting and the post emergence herbicides were applied at 15 days after transplanting (DAT). The second crop of rice was taken immediately after the first crop without disturbing the field layout. The results of the field experiments revealed that an integrated strategy involving intensive tillage (three ploughings fb puddling), deep water ponding (ie., > 7.5 cm upto panicle initiation and saturation thereafter ) and application of azimsulfuron @ 35 g ha-1 at 3-5 leaf stage of the weed was the most efficient treatment for managing the weed in terms of weed control efficiency (WCE), crop performance and net income. Preplant application of oxyflourfen @ 0.15 kg ha-1 fb hand weeding when combined with deep water ponding and intensive tillage recorded high WCE but was inferior in terms of economics. Combinations of these modified cultural practices with manual weeding though uneconomic, was efficient in managing the weed and recorded high yield also and hence could be an option for organic rice cultivation. The results from soil seed bank studies revealed that the density of blood grass propagules in the soil could be significantly reduced through intensive tillage and continuous maintenance of > 7.5 cm water level in the field. Among the weed management practices, application of azimsulfuron recorded the lowest weed seed density in the soil. When compared to the weedy check combinations, the soil seed bank was considerably lower in all the other treatments. The response of the microbial community to varying concentrations of the herbicides included in the study was assessed by conducting a separate field experiment which was laid out in RBD with 3 replications. The treatments were : oxyflourfen @ 150, 300, 450 g ha-1, azimsulfuron 35, 70, 105 g ha-1, bispyribac sodium +metamifop @ 70 , 140, 210 g ha-1, fenoxyprop- p-ethyl @ 60, 120, 180 g ha-1 and untreated control. The results showed that the bacterial population was stimulated with each increment of the herbicide concentrations. The fungal and actinomyctes population declined significantly immediately after the herbicide application but the negative impact was only transient and in most of the treatments the population recovered within two weeks. The soil enzyme activity was also found positively influenced by the herbicide application. From the results it was concluded that an integrated strategy involving intensive tillage (three ploughings fb puddling), deep water ponding (ie., > 7.5 cm upto panicle initiation and saturation thereafter ) and application of azimsulfuron @ 35 g ha-1 at 3-5 leaf stage of the weed was very effective for managing blood grass. Similarly application of oxyflourfen, bispyribac sodium + metamifop and fenoxyprop- p-ethyl at the recommended dose did not show any negative impact on the microbial community in the wetland rice ecosystem.ThesisItem Open Access Productivity and soil health of rice based cropping systems under organic management(Department of Agronomy, College of Horticulture, Vellanikkara, 2018) Rajanand Hiremath; KAU; Usha, K EThe study entitled “Productivity and soil health of rice based cropping systems under organic management” was conducted in the Department of Agronomy, College of Horticulture, Vellanikkara during 2015-2017 to find out the suitable rice based cropping system under organic management. The experiment was laid out in randomized block design with three replications. Rice was grown under four different cropping systems for two consecutive years with and without foliar spray of liquid organic manures (LOMs). The rotations followed were rice-rice-njavara rice, rice-rice-salad cucumber, rice-rice- vegetable cowpea, rice-rice-amaranthus and rice-rice-fallow. The management practices were followed as per the Package of practices recommendations: (Ad hoc) for organic farming: Crops of the Kerala Agricultural University. Jeevamrurtham, Panchagavyam, green leaf extract and fish amino acid were the liquid organic manures sprayed at 15 days intervals after transplanting. The growth and yield parameters of all the crops were found to be better with the application of liquid organic manures. All the crops performed well in the second year due to the significant effect of crop diversification, residual effect of manures applied for the preceding crop and the improvement in soil health. There was significant reduction in the number of weeds, pests and diseases associated with rice due to crop rotation under organic management. Rice-rice-salad cucumber with and without LOMs produced significantly higher rice equivalent yield (29.58 and 24.67 t ha-1 respectively) and system productivity (81.03 and 67.58 kg ha-1 day-1 respectively) than rest of the sequences. Better sustainability yield index was recorded in rice-rice-vegetable cowpea with LOMs (0.26) followed by the same system without LOMs (0.20). With 300% cropping intensity, rice-rice-salad cucumber with and without LOMs recorded higher gross return (11,20,180/ 9,57,423 ₹ ha-1 respectively) and net return 237 (7,25,126/ 5,74,416 ₹ ha-1 respectively) compared to rice-rice-fallow with 200% cropping intensity (3,27,039 ₹ ha-1 gross return and 1,72,539 ₹ ha-1 net return). Among the sequences, the B:C ratio was found to be the highest in rice-rice-vegetable cowpea with and without LOMs (2.99 and 2.76 respectively). The soil characters were also significantly influenced by the treatments. The decreasing trend in bulk density is an indication of improvement in porosity and water holding capacity of the soil in the long run. Rice-rice-vegetable cowpea with LOMs recorded the highest organic carbon (1.46%), available N and P content (192.04 and 71.11 kg ha-1 respectively) while rice-rice-salad cucumber with LOMs had the highest available K content (332.78 kg ha-1). Total microbial biomass (bacteria, fungi and actinomycetes) and dehydrogenase activity were found to be the highest with rice-rice- vegetable cowpea with and without LOMs followed by rice-rice-salad cucumber with and without LOMs. The highest soil health index was registered by rice-rice-vegetable cowpea with and without LOMs (3.34 and 3.00 respectively) followed by rice-rice- amaranthus. The study revealed that foliar application of liquid organic manures enhanced the soil health and productivity of rice as well as other crops grown in rotation. Rice-rice- salad cucumber was found to be the best rice based cropping system with maximum net return, whereas rice-rice-vegetable cowpea system improved the soil physical, chemical and biological properties and thus sustained the soil health.ThesisItem Open Access Invasion impact of greater club rush (Scirpus grossus L.f) on wetland rice ecosystem(Department of Agronomy, College of Agriculture, Vellayani, 2017) Gayathri Karthikeyan, P; KAU; Sansamma GeorgeThe study entitled “Invasion impact of greater club rush (Scirpus grossus L. f) on wetland rice ecosystem” was conducted at College of Agriculture, Vellayani during 2015-2017. The objectives were to study the invasive characteristics, habitat affinity and distribution of greater club rush, to assess its invasion impact on biodiversity and ecosystem functioning of the wetland ecosystem and also to develop an ecofriendly management strategy for recovering the invaded fields. To achieve the objectives, the study covered four aspects, i.e. Part I. Weed mapping and habitat analysis, Part II. Study of invasive characteristics of greater club rush, part III. Invasion impact on biodiversity and ecosystem functioning of wetlands, Part IV. Management of greater club rush. A preliminary survey on the presence of the emergent hydrophyte in Thiruvananthapuram district indicated that the invasion was mainly concentrated in some pockets in the wetlands adjoining the Vellayani fresh water lake. Hence, the wetland ecosystem of the Vellayani lake watershed was selected as the geographical unit for conducting the investigation. Under Part I, the extent of greater club rush invasion in the wetlands of Thiruvananthapuram district was assessed and mapped using Global Positioning System (GPS) and Geographical Information System (GIS). As per local enquiries, the invasion was noticed for the first time about 15 - 20 years back and was spreading fast in waterlogged paddy fields. However, it was not clear how this alien weed was introduced and naturalised in Kerala. The results of the weed mapping studies revealed that greater club rush invasion was concentrated mainly in the north - western side of wetlands adjoining the Vellayani lake. From the drainage and land use maps, it was inferred that there was a flood plain formed in the locality due to indiscriminate wetland reclamation resulting in impeded drainage. The total area under invasion was approximately 65 ha (47.70 per cent of the rice fallows). During the mapping studies, it was also observed that the ownership of a major portion of these paddy fields was vested with absentee landlords who leave the land uncultivated for a long time thus providing open niches for further spread of the weed. Correlation studies on weed density and dry weight with soil and water parameters of the invaded fields indicated that the weed has high level of habitat tolerance and ecological flexibility and was able to thrive under a wide range of field conditions. Under Part II, the invasive nature of greater club rush was assessed by observing the growth and development characteristics of the weed under field conditions. From the results, it was inferred that, tall stature (1.52 m), dense growth habit (342.23 ramets m-2), low light infiltration (4.36 per cent), high relative growth rate (0.028 g g-1 day-1), efficient propagation (rhizomes, stolons and corms combine for multiplication and perennation), huge biomass (30 t ha-1) and abundance of aerenchyma along with ecological flexibility imparts intense competitiveness for greater club rush making it a successful invader. The major part of the study was to assess the impact of greater club rush invasion on the wetland ecosystem (Part III). Based on the weed mapping and habitat analysis, three heavily infested padasekharams, located within a distance of 5 km were selected for the impact study and monitored for two years. The methodology used was Multisite comparison of the co- existing flora and fauna community, between invaded vs uninvaded sites. Alterations in nutrient cycling and microbial activity due to the invasion were studied by collecting and analyzing soil samples from selected sites during three seasons. The results indicated that greater club rush invasion was depleting the diversity of native vegetation in the wetland ecosystem in terms of species richness and also density. Soil seed bank studies also confirmed the negative impact of the invasion on flora diversity. However, the invaded fields were observed to be rich in faunal diversity and an ideal home for several water birds especially purple moorhen. The thick stand of the weed was found to provide refuge to small animals like rats and snakes also; and these in general were causing trouble to rice farmers in adjacent areas. Contrary to several earlier reports, the impact on the ecosystem functioning parameters was negligible, probably due to occasional flooding and sedimentation in the selected locality. To develop an eco-friendly strategy for managing the weed, an experiment was undertaken in a heavily infested paddy field (Part IV) with eight treatments and three replications and the design was RBD. The treatments were: T1 - (Bensulfuron methyl + Pretilachlor) @ 660g ha-1 on the next day of tilling., T2 - (Bensulfuron methyl + Pretilachlor) @ 1320g ha-1 on the next day of tilling, T3 –Azimsulfuron @ 35g ha-1 at 3-5 leaf stage , T4 -Azimsulfuron @ 70 g ha-1 at 3-5 leaf stage, T5 - (Glyphosate @ 1.0 kg ha-1 + 2, 4 – D sodium salt @ 2.0 kg ha-1) at active growth stage, T6 - (Glyphosate @ 0.5 kg ha-1 + 2, 4 – D @ 1.0 kg ha-1) at reproductive stage, T7 -Tillage (Farmer’s practice) and T8 – Control (Uninterrupted weed growth). Among the various treatments, application of Glyphosate @ 0.5 kg ha-1 + 2, 4 – D @ 1.0 kg ha-1 at the reproductive stage was found to be the best, giving complete weed kill with no further regrowth. The opportunities for utilising the weed and thereby managing it were also investigated during the study. The results revealed that greater club rush with its huge biomass production (>30 t ha-1) could remove many of the heavy metals (arsenic, copper, zinc, lead, chromium, cobalt, nickel and chromium) from contaminated soils more efficiently than water hyacinth which is a well known phytoremediator. The nutritive value of the weed biomass (crude protein - 7.5 per cent, crude fibre- 26.79 per cent) was shown to be comparable with that of guinea grass (crude protein - 8 to14 per cent, crude fibre - 28 to 36 per cent). The K/(Ca+Mg) ratio was 1.39 which is considered to be within safe limits in a livestock feed. However being a phytoextractor, further studies needs to be done for justifying its use as a forage. The study revealed that greater club rush has high level of ecological flexibility and competitiveness which make it a successful invader. The weed has already invaded considerable area of wetland rice ecosystem and is likely to spread further in areas left fallow for long periods. It was found that the invaded fields could be efficiently recovered by application of a tank mixture of glyphosate @ 0.5 kg ha-1 + 2, 4 – D sodium salt @ 1.0 kg ha-1 at the reproductive stage. The major negative impact of the invasion on ecosystem was the decline in species richness and density of native weed community. At the same time, the thick weed growth provided ideal habitat for many faunal species. The weed was found to have the potential to be used for phytostabilisation of heavy metal contaminated soils and the luxuriant biomass had reasonable nutritive value also. The overall conclusion is that greater club rush invasion can become a potential threat to the wetland rice ecosystem, if left undisturbed.ThesisItem Restricted Acidity amelioration and nutrient management practices for mitigating yield constraints of rice in Vaikom Kari(Department of Agronomy, College of Agriculture, Vellayani, 2017) Devi, V S; KAU; Kumari Swadija, OAn investigation entitled “Acidity amelioration and nutrient management practices for mitigating yield constraints of rice in Vaikom Kari” was carried out as two field experiments in Vaikom Kari soils of Kuttanad during the period from 2014 to 2017 to standardize acidity amelioration and nutrient management practices for rice to overcome yield constraints in Vaikom Kari and to work out the economics of cultivation. Experiment I entitled “Evaluation of acidity amelioration practices for rice in Vaikom Kari” was conducted in farmer’s field in Kallara panchayat in Kottayam district during November 2014 to March 2015. The experiment was laid out in RBD with seven treatments in three replications with rice var. Uma. The treatments included lime, dolomite and rice husk ash (RHA) applied as two splits- as basal + 30 DAS or as basal + one week before third dose of fertilizer application and a control without ameliorants. Lime, dolomite or RHA, irrespective of time of application, could produce taller plants with higher LAI and tiller number at maximum tillering (MT), panicle initiation (PI) and harvest stages. The same treatments recorded higher number of panicles m-2 and 1000 grain weight and lower sterility percentage. Lime, dolomite or RHA as basal + 30 DAS produced significantly higher grain yield over control. Grain yield was significantly and positively correlated with LAI at MT and PI stages and panicle number m-2. Higher straw yield was obtained with lime or dolomite as basal + 30 DAS and RHA treatments. Application of lime, dolomite or RHA as basal + 30 DAS resulted in higher dry matter production at harvest. Soil ameliorants improved the uptake of macronutrients and micronutrients. Uptake of N and K were significantly higher for lime, dolomite or RHA applied as basal + 30 DAS while dolomite as basal + 30 DAS recorded the highest P uptake. The highest uptake of Ca was found with lime as basal + 30 DAS and that of Mg and S with dolomite as basal + 30 DAS. The highest uptake of Mn and Zn were observed with lime as basal + 30 DAS, Cu with RHA as basal + 30 DAS and that of B with lime, dolomite or RHA applied as basal + 30 DAS. The control treatment and RHA applied as basal + one week before PI registered lower Na uptake and both RHA treatments registered higher Al uptake. There was significant and positive correlation of grain yield with uptake of nutrients except Fe, Zn and Al. Lime and dolomite treatments were more effective in reducing soil acidity and improving dehydrogenase activity and nutrient availability in the soil. The ameliorated plots showed higher organic carbon status compared to control. Lime as basal + one week before PI and dolomite treatments recorded higher soil available N at seedling stage and at tillering and PI stages, any treatment except control could register higher available N in the soil. Any liming material applied as basal + 30 DAS improved soil available P status. No significant effect of treatments on available K was observed. Lime or dolomite treatments resulted in higher availability of Ca while dolomite treatments registered higher availability of Mg in the soil. At all stages except harvest, the control plots recorded significantly higher status of available S and Fe and lower status of Mn in the soil. Significant and positive correlation of pH with available Ca and negative correlation with available Fe was observed at all stages of crop growth. Soil available Cu status was the highest with control at PI stage and with dolomite at harvest stage. Dolomite treatments recorded higher available B in the soil. The highest Na content in the soil was registered by dolomite treatments at seedling stage and by control at tillering stage. There was an increase in the availability of Na at all stages of experimentation but the content was below the critical level of toxicity. Soil exchangeable Al status was significantly higher in the control. Lime, dolomite or RHA applied as basal + 30 DAS gave higher net income and BCR while the control recorded the lowest net income and BCR. Experiment II entitled “Standardization of nutrient management practices for rice in Vaikom Kari” was conducted during August to December 2015 and 2016 in farmers` fields in Thalayazham panchayat in Kottayam district. The experiment was laid out in RBD with 16 treatments (formulated based on the results of the Experiment I) in three replications with rice var. Uma. The treatments were dolomite, lime + MgSO4 or RHA + MgSO4 along with 100% POP alone or with 100% POP + foliar spray of 13:0:45 (1%) or borax (0.5%) or 13:0:45 + borax at PI stage. Lime + MgSO4 + 75% POP + 13:0:45 + borax as well as lime without MgSO4 + 100% POP combined with 13:0:45 or borax or both were also included as treatments. The treatments involving dolomite and lime with or without MgSO4 produced taller plants, higher tiller number m-2 and higher LAI during both the years. Dolomite + POP + 13:0:45 produced the highest number of panicles m-2. Higher test weight and lower sterility percentage were observed with dolomite + POP + 13:0:45 and dolomite + POP + 13:0:45 + borax. Higher grain yield of 5.42 and 5.57 t ha-1 during 2015 and 2016 respectively were produced by dolomite + POP + 13:0:45 followed by dolomite + POP + 13:0:45 + borax and lime + MgSO4 POP + 13:0:45. Grain yield was significantly and positively correlated with LAI at MT and PI stages and with panicle number m-2. Pooled analysis also proved the significance of the above treatments in producing higher grain yield. Lower yields were produced by the treatments involving RHA and 75% POP during both the years and in the pooled data. In general, higher straw yields were noticed with the treatments involving dolomite or lime along with foliar spray of 13:0:45 or 13:0:45 + borax. Higher dry matter production was noticed with dolomite + POP along with 13:0:45 or borax during first year and with dolomite + POP or lime + MgSO4 + POP along with 13:0:45 or 13:0:45 + borax during second year. In general, higher uptake of macronutrients and micronutrients was observed with dolomite or lime + MgSO4 treatments along with 100% POP during both the years. Uptake of Na was the highest with RHA + MgSO4 + POP + 13:0:45 during first year and with dolomite treatments during second year. Higher Al uptake was observed with lime + POP + 13:0:45 with or without MgSO4. Significant and positive correlation of grain yield with uptake of P, K, Ca, Mg, S, Mn, Zn, Cu and B and negative correlation with Fe was observed during first year. During second year, the yield was significantly and positively correlated with uptake of nutrients except Na and Al. The treatments involving dolomite, lime with or without MgSO4 performed better in ameliorating soil acidity than RHA treatments during both the years. The treatments involving RHA showed higher EC values. All the treatments except those involving RHA helped in improving dehydrogenase enzyme activity in the soil during the cropping period. The initial soil organic carbon status was maintained during the cropping period due to nutrient management practices. Availability of N in the soil improved due to treatments involving dolomite + POP during seedling stage and due to those involving lime + POP without MgSO4 at other stages. The treatments involving dolomite + POP and lime + POP with or without MgSO4 recorded higher available P during all crop stages. In general, higher status of available K was registered by the treatments involving RHA or lime without MgSO4. All treatments involving lime or dolomite registered higher soil available Ca and those involving dolomite or lime + MgSO4 showed higher availability of Mg in the soil. In general, available S in the soil decreased from initial status during the cropping period. The treatments involving dolomite registered lower status of soil available Fe and higher status of available Mn and B. Higher status of available Zn was registered by the treatments involving dolomite or lime + MgSO4. The treatments involving dolomite, lime + MgSO4 or RHA + MgSO4 along with POP registered higher available Cu in the soil. Dolomite treatments recorded lower status of Na and exchangeable Al in the soil. Soil pH was significantly and positively correlated with available P and significantly and negatively correlated with available Fe and exchangeable Al in the soil. The economics of cultivation in terms of net income and BCR were the highest with dolomite + POP + 13:0:45 during both the years which was closely followed by dolomite + POP + 13:0:45 + borax. The treatments involving RHA and 75% POP registered lower net income and BCR. The results of the study revealed the superiority of dolomite for ameliorating soil acidity in Vaikom Kari soil compared to lime or rice husk ash. Split application of dolomite as basal dose and at 30 DAS proved more effective than application as basal dose and one week prior to fertilizer application at panicle initiation stage. Soil acidity amelioration with dolomite @ 500 kg ha-1 (300 kg as basal dose and 200 kg ha-1 at 30 DAS) and soil application of 90:45:45 kg NPK ha-1 (full P as basal and N and K in three equal splits at 20 DAS, 35 DAS and PI stage) along with foliar spray of 13:0:45 (1%) or combined spray of 13:0:45 (1%) and borax (0.5%) at panicle initiation stage resulted in higher productivity and profitability from rice cultivation in Vaikom Kari soil.ThesisItem Open Access Precision farming in banana (musa AAB nendran ) for productivity enhancement(Department of Agronomy, College of Agriculture, Vellayani, 2017) Pintu Roy, Vattakunnel; KAU; Sheela, K RAn investigation entitled “Precision farming in banana (Musa AAB Nendran) for productivity enhancement” was undertaken during 2014-2017 to assess the influence of land management practices and lime application on growth and yield of banana, to standardize the fertigation schedule for yield improvement, to work out the economics and to study the nutrient dynamics under soil and fertigation systems of nutrient application. The study consisted of two experiments carried out simultaneously for two years from March 2015 to May 2017 in the farmer’s field at Pirappancode, Thiruvananthapuram. The first experiment on “Soil management and fertigation studies in banana” was laid out in split plot design with 12 treatment combinations and two controls each replicated thrice. The main plot treatments were the combinations of land management practices (l1- conventional land management and l2- land management for precision farming) and lime application{c1 – as basal at the time of pit preparation and c2 – applied in 2 splits (1/2 basal+1/2 at 4 MAP)} and the sub plot treatments were three levels of fertigation (n1-60 % recommended dose (RD) of N & K; n2- 100 % RD of N & K and n3-140 % RD of N & K). The two controls maintained were KAU adhoc recommendation for precision farming (control 1) and KAU POP (control 2). Lime requirement was calculated based on initial pH and applied as per the treatment. As the P status of the soil was high, P was applied @ 75 % RD for all treatments except control 1. Basal application of FYM @ 15 kg plant-1 and two bunch sprays with 3 % SOP were given uniformly for all the treatments. Precision land management practice (L2) improved growth attributes viz. LAI and total dry matter production (TDMP) and yield attributes like number of fingers in D hand (9.89) during first year and number of fingers bunch-1 (67.71) during second year. L2 also improved quality attributes like TSS and total sugar during second year and reducing sugar and total P uptake during both the years. Pooled analysis indicated the superiority of precision land management practice on yield (28.3 t ha-1). Basal application of lime (C1) resulted in higher LAI, TDMP, number of fingers bunch-1 (67.78), number of fingers D hand-1 (11.08), D finger weight (163.26 g), bunch weight (11.27 kg) and total K uptake during second year. Quality parameters viz. TSS, and sugar acid ratio during first year and pulp peel ratio during second year were also more for C1. Basal application of lime significantly increased the second year yield (28.19 t ha-1) and pooled yield (28.96 t ha-1). Higher growth attributes viz. LAI and TDMP and NPK uptake were observed with N2 during first year and N3 during second year. However, N2 and N3 were on par with respect to N uptake during first year and P uptake during second year. Among yield attributes, weight of D finger (223.71 g) was more with N2 during first year and higher number of fingers bunch-1 was obtained with N2 (66.66) and N3 (68.19) during second year. Fertigation of 60 % RD of N & K significantly improved fruit quality. Pooled yield was higher with fertigation of 100 % and 140 % RD of N & K (28.68 t ha-1 and 27.63 t ha-1 respectively). All treatment combinations resulted in improved growth and yield over control 2. Precision land management and basal application of lime with fertigation of 60, 100 or 140 % RD of N & K recorded higher yield (30.38, 30.87 and 28.77 t ha-1 respectively). Fertigation treatments and adhoc recommendation resulted in yield improvement by 30.83 % and 21.61 % respectively over soil application. Precision land management practices and fertigation of 100 % RD of N & K significantly improved water use efficiency (WUE) and water productivity during the first year while fertigation of 100 % and 60 % RD of N & K recorded higher water productivity application during second year. Application of entire quantity of lime as basal enhanced WUE during both the years. Drip irrigation enhanced WUE and water productivity over basin irrigation. Compared to soil application of 100 % RD of N & K, fertigation with the same nutrient level resulted in higher nutrient use efficiency and agronomic efficiency. All treatment combinations recorded higher gross income, net income and B: C ratio when compared with controls. Among the combinations, precision land management with basal application of lime and fertigation with 60 % RD of N & K recorded higher B: C ratio (3.75). The second experiment on “Nutrient dynamic studies in banana” was carried out with the treatment combinations involving fertigation of 100 % RD of N&K (l1c1n2, l1c2n2, l2c1n2 and l2c2n2) of the first experiment along with controls. Observations on pH, organic carbon (OC), primary, secondary and micro nutrient status in both soil and plant were taken at bimonthly interval. Dynamics on soil pH duirng first year and NH4-N and S during both the years indicated an initial increase upto 4 MAP followed by a decline at 6 MAP and again a slight increase at harvest stage of the crop. However for pH during second year and K content during first year, a slight decrease was noticed towards the harvest stage. In general, an increasing trend in NO3-N content in the soil was observed from initial stage to harvest stage of the crop. An increasing trend in OC and P contents were also observed in the soil. In general, build up of Ca and Mg in the soil was noticed after two years of experimentation. Changes in soil pH and nutrient content under fertigation and soil application of fertilizers indicated that soil application resulted in higher pH during first year while fertigation enhanced pH during second year especially during grand growth phase (6 MAP). The OC content recorded varying response during both the years. Fertigation resulted in higher NO3-N content in soil throughout the growth stages except at 6 MAP during first year and 6 MAP and at harvest during second year. Soil application of fertilizers resulted in higher K content in the soil throughout the growth stages during first year while fertigation enhanced K availability during early crop growth stages during second year. Availability of Ca and Mg in the soil was more for fertigation compared to soil application of fertilizers especially during grand growth phase. Fertigation improved S availability only at 4 MAP and at harvest. Correlation study revealed significant and positive correlation of bunch weight with Mg content and N/K ratio in the soil during first year and N, K, Ca and Mg contents and N/P, Mg/P, Ca/Fe and Ca/Mn ratios during second year. Significant and positive correlation of bunch weight was also observed with K, Mn and B contents in the plant during first year and Ca and Cu contents and Ca/Fe and Ca/Mn ratios during second year. The results of the present study revealed that precision land management practice (deep ploughing to a depth of 50 cm, raised beds to a height of 30 cm, taking pits and planting) along with basal application of FYM, P (based on soil P status) and lime (based on soil pH) and fertigation of 60 % RD of N & K (urea @ 390 g plant-1 and MOP @ 450 g plant-1) is the best management practice to increase yield and profitability of Nendran banana. Fertigation can be given at weekly interval starting from the first month of planting. Soil nutrient dynamics was found to be influenced by rainfall pattern, growth stage of crop and nutrient interactions. In general, fertigation improved the nutrient availability over soil application.ThesisItem Open Access Tillage and nutrition for productivity enhancement in tannia (Xanthosoma sagittifolium"(L.) schott)(Department of Agronomy, College of Agriculture, Vellayani, 2017) Atul Jayapal; KAU; Kumari Swadija, OAn investigation entitled ‘Tillage and nutrition for productivity enhancement in tannia (Xanthosoma sagittifolium (L.) Schott)’ was undertaken at College of Agriculture, Vellayani to identify ideal tillage system for productivity enhancement in tannia, to study the effect of soil conditioners and to compare the effects of integrated and organic nutrition on growth, yield and quality of tannia and to work out the economics of cultivation. The field experiments were conducted in the Instructional Farm attached to College of Agriculture, Vellayani from August 2014 to May 2015 and repeated during May 2015 to February 2016. The field experiment was laid out in split plot design with 24 treatment combinations and four replications. The main plot treatments consisted of four tillage systems (l1- conventional tillage followed by pit system, l2- conventional tillage followed by mound system, l3- deep tillage followed by pit system and l4- deep tillage followed by mound system) and sub plot treatments were combinations of two soil conditioners along with a control (s1- control, s2- coir pith @ 500 g plant-1 and s3- rice husk @ 500 g plant-1) and two nutrient management practices (n1- integrated nutrient management (INM) – FYM @ 25 t ha-1 + 80:50:150 kg NPK ha-1 and n2- organic nutrition- FYM @ 37.5 t ha-1 + wood ash @ 2 t ha-1).In the case of INM, half the quantity of FYM and full P were applied as basal dose and remaining FYM and full N and K were applied in three equal splits each at two, four and six months after planting along with interculture and earthing up. For organic nutrition, 2/3rd quantity of FYM was given as basal dose and remaining FYM and wood ash were given in three equal splits each at two, four and six months after planting along with interculture and earthing up. Dolomite @ 1 t ha-1 was applied uniformly to all plots at land preparation. Growth characters like plant height, leaf number plant-1and leaf area index were improved by deep tillage followed by pit system of planting. Application of coir pith as soil conditioner profoundly influenced growth characters. Organic nutrition was found superior to INM in improving growth characters. Yield components like cormel number plant-1, cormel and corm yield plant-1 and cormel: corm ratio were significantly higher due to deep tillage followed by pit system of planting. Application of coir pith as soil conditioner registered significantly higher values of yield components. Organic nutrition proved its superiority over INM in influencing the yield components. Cormel yield was found to be significantly and positively correlated with leaf area index at five months after planting, cormel number plant-1 and cormel : corm ratio. Significantly higher cormel yield (5.15 t ha-1) and corm yield (7.73 t ha-1) were obtained due to deep tillage followed by pit system. Deep tillage resulted in 24 per cent increase in yield over conventional tillage and pit system of planting registered 28 per cent increase in yield over mound system. Coirpith as soil conditioner resulted in higher cormel yield of 4.51 t ha-1 (11 per cent increase in yield over control) and corm yield of 6.99 t ha-1. Organic nutrition significantly improved cormel yield (4.52 t ha-1 which was 12 per cent higher than due to INM) and corm yield (7.07 t ha-1) compared to INM. Pooled analysis indicated that interaction of deep tillage followed by pit system with coir pith as soil conditioner and organic nutrition (l3s2n2) recorded the highest cormel yield (5.77 t ha-1) and the same treatment, but with rice husk as soil conditioner (l3s3n2) recorded the highest corm yield (8.3 t ha-1). Deep tillage followed by pit system, application of coir pith as soil conditioner and organic nutrition compared to INM recorded significantly higher dry matter production and harvest index. Quality characters of cormel like dry matter, starch and protein contents were improved due to deep tillage followed by pit system among tillage systems, application of coir pith as soil conditioner and organic nutrition compared to INM. In general, a shelf life of one month for cormel was observed without any microbial decay, sprouting and appreciable physiological loss in weight. Higher uptake of N, P and K were noticed due to deep tillage followed by pit system. Coir pith as soil conditioner proved its superiority in enhancing nutrient uptake. Uptake of nutrients was significantly higher under organic nutrition than under INM. Tillage systems, soil conditioners and organic nutrition profoundly influenced the physico-chemical properties of the soil after the experiment. Bulk density was lowered and porosity and water holding capacity were improved due to deep tillage, application of rice husk as soil conditioner and organic nutrition. Correlation study revealed significant and negative correlation of yield with bulk density and significant and positive correlation with porosity and water holding capacity of the soil. Organic nutrition resulted in significantly higher status of organic carbon and available N, P and K in the soil compared to INM. Significantly higher net income and benefit cost ratio could be realized due to deep tillage followed by pit system among tillage systems, application of coir pith as soil conditioner and organic nutrition compared to INM. Considering interaction effects, deep tillage followed by pit system without soil conditioner under organic nutrition (l3s1n2) registered higher net income and benefit cost ratio. It is evident from the present study that deep tillage to a depth of 30 cm followed by pit system of planting is ideal for productivity enhancement in tannia. Application of coir pith as soil conditioner and organic nutrition improved the growth, yield and quality of tannia.Deep tillage followed by pit system and organic nutrition (FYM @37.5 t ha-1 + wood ash @ 2 t ha-1) can be recommended for economic production of tannia. Wherever coir pith or rice husk is available at a cheaper rate, it can be applied as soil conditioner @ 500 g plant-1 for enhanced productivity of tannia.ThesisItem Open Access Biology and management of weedy rice (Oryza sativa f. spontanea)(College of Horticulture, Vellanikkara, 2015) Nimmy, Jose; KAU; Abraham, C TWeedy rice is the complex of morphotypes of Oryza species widely distributed in the commercial rice fields in more than 50 countries of Asia, Africa and Latin America, especially in areas where farmers have switched to direct seeding due to labour shortage and high cost. Taxonomically, Indian weedy rice is identified as Oryza sativa f. spontanea which belongs to the indica group. Invasion and spread of weedy rice in the cultivated rice fields have forced the farming community to abandon rice farming, leading to socio economic and ecological impacts in the rice bowls of Kerala. Management of weedy rice infestation is complex mainly because of its morphological similarities to cultivated rice and lack of herbicides for selective control of weedy rice in cropped fields. Hence, the present research programme was undertaken to estimate the extent of infestation of weedy rice in rice bowls of Kerala, to study the biology and ecology, and to chalk out strategies for integrated management of weedy rice. Survey conducted in the major rice belts of Kerala, viz., Kole, Kuttanad and Palakkad, revealed that more than 65 percent of the area has low to severe weedy rice infestation. In the major rice bowls of Kerala there was severe, moderate and low infestation of weedy rice in 26, 36 and 49 panchayaths, respectively,. The extent of infestation was more in Kuttanad in Alleppey, Kottayam and Pathanamthitta districts and Kole lands of Thrissur district. In Palakkad region, the infestation was more in panchayaths of Alathoor and Nemmara blocks. Survey revealed the presence of weedy rice variants with respect to morphological characters like number of tillers per plant, height of plant, length of ligule, panicle characters, colour of grains, and length and colour of awns. Studies conducted on the germination of weedy rice seeds revealed that there was no significant difference between the germination of weedy rice in the presence and absence of rice seeds in the soil. It was noticed that seed germination was higher at the surface and 2 cm depth of the soil and there was drastic reduction in the germination from deeper layers of 4-8 cm. Investigations on dormancy revealed that hull induced dormancy in weedy rice could be broken by exposing seeds to 20ºC for 48 hours, treating with 0.6% nitric acid for six hours, rupturing seed coat, or maintaining electrical conductivity of 5 dS m-1 for six hours in the growing media. Scanning electron microscope studies confirmed that lesser overlapping of lemma and palea contributed to quicker germination of half mature straw coloured weedy rice grains whereas, slow germination in black coloured mature seeds is due to the clear overlapping of lemma and palea. Presence of more number of stomata both on adaxial and abaxial surface, silica deposits and hairy out-growths on leaf, and high root volume in weedy rice contributed to its early vigour, growth and competitiveness. Management options found effective for the control of weedy rice in direct seeded puddled rice include (1) pre sowing surface application of oxyfluorfen @ 0.2 kg ha-1 three days before sowing in thin film of water (2) selective drying of weedy rice panicles with nonselective broadspectrum herbicides glufosinate ammonium or glyphosate @ 15 % - 20 % concentration at 60-65 DAS using specially designed wick applicator/wiper device (3) stale seed bed technique with (wet tillage in between two stales under heavy infestation) application of broad spectrum herbicide followed by flooding for exhausting soil seed bank (4) straw burning after harvest of infested fields followed by zero tillage in succeeding crop and (5) soil solarisation for more than 30 days during summer months using 100 micron transparent polythene sheets. A novel hand held wiper device was developed for the direct contact application of nonselective broadspectrum herbicides for selective drying of weedy rice panicles at 60-65 days after sowing, when rice and weedy rice plants maintain height difference of 20 cm. The device was filed for Indian Patent at Patent Office, Chennai (Application No. 1763/CHE/2014 dated 01.04.2014). Effective and economical management of weedy rice is possible by the integrated use of different options for management depending on the intensity of infestation. Various weedy rice management options standardized in the present study were demonstrated in farmers’ fields in a participatory mode. The demonstrations have given good results and many farmers have already adopted the package for the integrated management of weedy rice.