PhD Thesis
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Item Valuing the Complementarity in Rice-Fish Integrated Farming: The Case of Pokkali Ecosystem(Department of Agricultural Economics, college of agriculture, Vellanikkara, 2025-08-26) SUMITHRA,S; Indiradevi,PIntegrated Farming Systems (IFS) are known for their mutually complementary relations. The coastal saline ecosystem along the Ernakulam, Alappuzha and Thrissur districts of Kerala, referred to as Pokkali lands, follow the traditional practice of integrating paddy and fish/prawn farming. Despite the ecological resilience and economic viability, IFS in Pokkali ecosystem has experienced a significant decline in recent decades, shifting to monoculture practices of aquaculture. In this background, the study was conducted with the main objectives of understanding the dynamics of rice-fish rotational system and assessing the relative economics, estimating the economic value of complementarity between the systems based on empirical analysis, estimating the value based on stakeholder knowledge, and effecting the comparison between the two estimates. The study was conducted in Ernakulam district, which holds the largest share (64%) of Pokkali lands focussing on five prevalent farming systems: Rice–Prawn IFS, Rice–Fish IFS, Prawn monoculture, Fish monoculture, and fallowing. Multistage sampling method, was adopted with district, block panchayat (BP) and grama panchayat (GP) as the respective stages of selection. The BP and GP with highest area under respective farming practice were purposively selected, while the sample respondents were chosen on random basis. The total sample size was 250 farmers (random sample of 50 from each system) and 120 other stakeholders, which include officers of agriculture department as well as fisheries department, farm labourers, and general public, working/residing in the locality. Data was gathered from the respondents through personal interview method employing structured pre-tested interview schedule. Soil samples were also collected from the selected farms following IFS system, before and after the rice crop and were analysed in soil testing laboratory under KAU. Analytical tools employed include partial budgeting to assess the relative economics of various systems, productivity change method for capturing the positive externality due to complementarity in IFS, and contingent valuation method. The Pokkali ecosystem in Kerala, a unique agro-ecological unit, has witnessed significant decline over the past two decades. Though official data is not published, informal reports show Pokkali paddy cultivation area shrinking from about 25,000 hectares in the 1980s to merely 5,707 hectares by 2021, driven by low rice profitability, rising wages, labour scarcity, and large-scale land conversion for non-agricultural use. Remote sensing studies further underscore the impact of urbanization and infrastructure growth in altering land use patterns, along with a significant shift toward monoculture aquaculture, threatening the sustainability of this ecologically sensitive system. The Rice–Aquaculture IFS in Pokkali operates in a seasonal rotation: rice is cultivated from June to October, followed by prawn or fish farming from November to April. Despite receiving policy and legal support for rice component, subsidies and mandatory rice cultivation certificates for aquaculture licensing, the system faces declining trend. Rice cultivation yields 1,326 kg/ha, with negative net returns of ₹40,383/ha, it remains financially unviable without support. Conversely, prawn farming is capital intensive (₹2,01,889/ha) but highly profitable, yielding returns of ₹4,88,373/ha and net profit of ₹2,86,484/ha. Together, the rice–prawn IFS yields a total return of ₹5,57,325/ha with a net return of ₹2,46,101/ha and a favourable benefit-cost ratio (BCR) of 1.79. On the other hand, the rice–fish IFS, offers limited economic benefits with relatively low fish yield and losses from rice cultivation, this system yields only ₹10,028/ha in net returns and a marginal BCR of 1.03. Comparative analysis indicates prawn monoculture which is resource-intensive and environmentally less sustainable, generates lower net returns (₹1,68,338/ha) and a reduced BCR (1.60) compared to integrated systems, primarily due to higher operational expenses especially feed costs. Monoculture practice, particularly fish farming, delivers higher net returns (₹3,97,311/ha) and a BCR of 2.32 outperforming the rice–fish IFS, incentivizing farmers to abandon traditional IFS practices. The higher profitability in monoculture is primarily due to the ability to rear more number of fish species, including long-duration and high-value species. Such practices are not feasible in the rice-fish IFS, where aquaculture is typically restricted to six-months. However, partial budgeting reveals that shifting from monoculture to integrated farming results in net economic gains, particularly in the rice–prawn system, which offers an additional gain of ₹69,837/ha, despite higher cultivation costs. This gain stems from reduced input expenses in aquaculture (artificial feed, eradicants, electricity) and dual income sources. In monoculture systems, only aquatic species typically high-value prawns like Tiger prawns or commercially viable fishes are cultivated by skipping Pokkali rice cultivation. The relatively poor economic gains along with cultivation challenges act as major drivers for shifting from IFS to monoculture practices, which are very fast and visible in certain pockets like Kumbalam, Kumbalanghi, Chellanam panchayats. At the same time, the ecological complementarity in IFS, particularly the effect of improved soil quality, is also significant. Statistical analysis shows that a 1% increase in Soil Quality Index (SQI) leads to a 0.25% rise in rice yield, which is equivalent to 3.23 kg/ha or ₹167.96/ha. When scaled across 5,000 ha, the realized value of this yield benefit is ₹8.40 lakh. Empirical studies (Sreelatha and Joseph, 2019) confirm that IFS improves SQI by 41.6% over monoculture, equating to a benefit of ₹3.49 crore ecosystem-wide. The study underscores that IFS is both economically viable and ecologically beneficial, especially when complemented with improved management and varietal selection. High-yielding Pokkali varieties provide 29.14% higher yields than traditional types. Yet, current subsidy policies fail to incentivize full-cycle crop management, often resulting in low yield realization and misuse of support mechanisms. Additionally, perceived rice yield gains, though lower than realized, still affirm this ecological value, estimated at ₹97.76/ha. The undervaluation of soil quality benefits among stakeholders reveals a critical perception gap, particularly among aquaculture farmers and fisheries officials, who tend to favour short-term economic returns from monoculture over long-term ecological gains. Stakeholder perceptions reveal wide variation. While agricultural officers’ express optimism about IFS yield potential, fisheries officials lean toward aquaculture. Farm labourers report higher perceived yields, reflecting their hands-on experience. Farmers practicing monoculture acknowledge the ecological benefits of IFS but cited labour shortages, profitability concerns, and climatic risks as key barriers. The study recommends scientific mapping of Pokkali areas using remote sensing, developing a database of Pokkali landholders, linking subsidy to yield or performance metrics to ensure proper crop management, applying externality gains in extension methods, strengthen compliance mechanisms to ensure rice cultivation precedes aquaculture licensing, reinforcing the Pokkali Land Development Authority and establishing targeted support programs to address region-specific socio-economic barriers, and considering the scope of introducing a targeted Green Granary Support Scheme for Pokkali farmers that provides financial incentives, technical support, and market linkages to promote eco-friendly farming practices. Further research focus is to be on assessing the role of water quality in influencing prawn/fish yield across IFS and monoculture systems, examining the efficacy of current subsidy schemes, conducting longitudinal studies on soil health, salinity, and system resilience. IFS being an effective system that ensures food security, profitability and sustainability, is considered as a powerful tool for enhancing the economic status of small and marginal farmers. There should be programme to conserve and support the traditional rice-fish IFS models, especially in view of the climate change challenges.Item Nitrogen use efficient varieties for enhanced productivity in rice (Oryza sativa L.)(Department of Agronomy, College of Agriculture, Vellayani, 2025-07-29) Merin Jose; Shalini Pillai, PThe research entitled “Nitrogen use efficient varieties for enhanced productivity in rice (Oryza sativa L.)” was conducted at the Department of Agronomy, College of Agriculture, Vellayani, during 2021 to 2025. The objectives of the study were to screen selected rice varieties for nitrogen use efficiency (NUE) based on germination and root characteristics, to evaluate the field performance of selected nitrogen-efficient rice varieties at graded doses of nitrogen (N), and to work out the economics. The study was conducted in three parts. The first part was a lab study wherein, 14 popular rice varieties released from Kerala Agricultural University (KAU) were screened for NUE based on germination characteristics. The experiment was laid out in completely randomized design (CRD) with 14 varieties and 5 media, replicated thrice. The treatments comprised seven short duration varieties (SDVs) viz., v1- Makom (MO 9), v2- Prathyasa (MO 21), v3- KAU Manuratna, v4- Jyothi (PTB 39), v5- Harsha (PTB 55), v6- Varsha (PTB 56) and v7- Kanchana (PTB 50) and seven medium duration varieties (MDVs) viz., v8- Bhadra (MO 4), v9- Uma (MO 16), v10- Sreyas (MO 22), v11- Pournami (MO 23), v12- KAU Manuvarna, v13- Athira (PTB 51) and v14- Aiswarya (PTB 52), and Modified Arnon Hoagland (AH) media [(m1- AH media with urea (7.5 mM), m2 - AH media with ammonium chloride (15 mM), m3- AH media without N source, m4- AH media and m5 - distilled water]. In general, the presence of urea or any other additional source of N tends to inhibit germination. However, this inhibitory effect was not observed in the case of Harsha (v5) and Varsha (v6), as both varieties took 39 h each to reach 50 per cent germination in distilled water and in AH media with urea. In the case of MDVs, the germination of all the varieties were inhibited. The SDVs, viz., Varsha (v6), Harsha (v5) and Prathyasa (v2) had longer shoots (10.25 cm ± 1.27 cm, 7.95 cm ± 0.52 cm and 6.63 cm ± 0.79 cm respectively) in the presence of urea as compared to distilled water. In the case of MDVs, Aiswarya (v14), Athira (v13), Sreyas (v10) and Uma (v9) produced longer shoots (9.20 cm ± 0.36 cm, 8.20 cm ± 0.39 cm, 8.13cm ± 0.85 cm and 6.53 cm ± 0.75 cm respectively) in the presence of urea as compared to distilled water. In the presence of urea, Varsha (v6) and Harsha (v5) recorded longer roots (9.13 cm ± 1.91 cm and 9.03 cm ± 2.78 cm). With respect to MDVs, Sreyas (v10) recorded longer roots (12 cm ± 0.28 cm) and this was on par (11.73 cm) with that under distilled water. Higher seedling dry weight (23.15 mg ± 2.25 mg) was recorded in Varsha (v6) which was on par with Kanchana (v7), Harsha (v5) and Jyothi (v4). In the presence of urea, Uma (v9) recorded higher seedling dry weight (23 mg ± 1.83 mg) which was on par with Aiswarya (v14), Sreyas (v10) and KAU Manuvarna (v12). Urease enzyme activity was found to be the highest (0.59 ± 0.01) mM NH4+ min-1 g-1 in Varsha (v6) followed by Harsha (v5). A similar trend was observed in urea and NH₄Cl, where Varsha (v6) recorded higher urease enzyme activity than Harsha (v5). In case of MDVs, urease enzyme activity was the highest (0.47 ± 0.01) mM NH4+ min-1 g-1 in Aiswarya (v14) followed by Sreyas (v10). Seedling vigour index I (SVI I) was higher in Varsha (v6) followed by Harsha (v5) and higher seedling vigour index II (SVI II) was recorded by Kanchana (v7), followed by Varsha (v6) and Harsha (v5). In case of MDVs, Aiswarya (v14) recorded higher SVI I (885.15), followed by Sreyas(v10) (717.28). Whereas, Sreyas (v10) recorded higher SVI II (2288.25) which was followed by Aiswarya (v14) (2278.50). The second part of the study comprised screening the 14 rice varieties in field, under two contrasting N levels. It was carried out in the wetlands of the Integrated Farming System Research Station (IFSRS), Karamana, during June to October 2023. The experiment was laid out in randomised block design (RBD) with the 14 varieties at two levels of nitrogen (n0- 0 % RDN and n1- 100 % RDN), replicated thrice. Among the SDVs, Harsha (v5) and Varsha (v6) and among MDVs, Sreyas (v10) and Aiswarya (v14) proved superior in terms of growth attributes including plant height, tillers m-2, rooting depth and root volume. The same trend was observed in yield attributes and yield. The lower percentage in yield reduction observed in Harsha (23.89%), Varsha (22.50%), Sreyas (27.89%) and Aiswarya (20.61%) at zero per cent RDN compared to 100 per cent RDN pointed towards their higher NUE. These varieties also exhibited higher root dry weight efficiency index (RDWEI) which is also an indicator of NUE. The Partial factor productivity of N (PFPN) also exhibited a similar trend. Based on the cumulative ranking of germination traits (part I) and RDWEI, yield and PFPN (part II) the varieties Harsha, Varsha, Sreyas and Aiswarya were chosen as promising candidates for further field evaluation aimed at validating their production potential, NUE and profitability. The third part of the study entitled ‘Field evaluation of nitrogen- efficient rice varieties’ was also conducted at IFSRS, Karamana from November 2023 to February 2024 (second crop 2023-’24 referred to as season I) and July to November 2024 (first crop 2024 ’25 referred to as season II). The field performance of the four nitrogen-efficient rice varieties chosen from part I and part II were assessed at graded levels of recommended dose of nitrogen (RDN). The experiment was laid out in split plot design with four main plots (n1- 100 % RDN, n2 - 75 % RDN, n3 - 50 % RDN and n4- absolute control) and four sub plots [v1- Harsha (PTB 55), v2- Varsha (PTB 56), v3- Sreyas (MO 22) and v4- Aiswarya (PTB 52)], replicated four times. The results revealed that during seasons I and II, while Harsha at 100% RDN (n1v1) recorded the highest grain yield (4567 kg ha-1 ± 64 kg ha-1 and 4703 kg ha-1 ± 35 kg ha-1 respectively), the yield of Varsha at 100% RDN (n1v2) (4507 kg ha-1 ± 81 kg ha-1 and 4720 kg ha-1 ± 89 kg ha-1) and 75 per cent RDN (n2v2) (4440 kg ha-1 ± 82 kg ha-1 and 4603 kg ha-1 ± 68 kg ha-1) were statistically comparable. The MDVs, Sreyas and Aiswarya also behaved in a similar manner with comparable yields at 100 per cent RDN and 75 per cent RDN. Chlorophyll content was significantly the highest at 100 % RDN in Harsha, Varsha and Sreyas throughout the growth stages. Whereas in Aiswarya, the chlorophyll content at 100 per cent RDN was statistically comparable to that at 75 per cent RDN. In terms of NUE indices, all the four varieties exhibited significantly higher PFPN and agronomic efficiency of nitrogen (AEN) at 50 per cent RDN. However, during season II AEN of both Varsha and Aiswarya at 50 per cent RDN and 75 per cent RDN were comparable. Harsha recorded the highest BCR (1.41± 0.02 and 1.45± 0.01) at 100% RDN (n1v1), while, Varsha recorded the same (1.42 ± 0.03 and 1.49 ± 0.02) at 75 per cent RDN (n2v2). Among the MDVs, Sreyas and Aiswarya recorded higher BCR at 75 per cent RDN. Screening of 14 popular rice varieties released from KAU based on germination characters, RDWEI and PFPN showed that the short duration varieties viz., Harsha (PTB 55) and Varsha (PTB 56) and the medium duration varieties viz., Sreyas (MO 22) and Aiswarya (PTB 55) could be considered as nitrogen efficient. Field evaluation of the nitrogen efficient varieties showed that while the productivity and profitability of Varsha could be sustained at 75 per cent RDN, the variety Harsha required 100 per cent RDN. The study also revealed that, the recommended dose of N (90 kg ha-1) for the nitrogen efficient MDVs, could be reduced by 25 per cent without compromising yield and profitability.Item Residue distribution and mobility of chlorantraniliprole formulations in soil and it's uptake by rice (Oryza sativa L.)(Department of Soil Science and Agricultural Chemistry, College of Agriculture,Vellayani, 2023-03-28) Greeshma Suresh.; Thomas GeorgeThe study entitled ‘Residue distribution and mobility of chlorantraniliprole formulations in soil and its uptake by rice (Oryza sativa L.)’ was conducted at the Department of Soil Science and Agricultural Chemistry and the laboratory attached to the All-India Network Project (AINP) on Pesticide Residues, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala during 2018-22. The main objectives of the experiment were to investigate and understand the persistence, transformation, and mobility of chlorantraniliprole in soils and leachate water and the uptake and dissipation of residues in rice (Oryza sativa L.) The study was conducted in laterite and coastal alluvium soils of Kerala. The representative soil samples of laterite soil were collected from the fields located within the campus of the College of Agriculture, Vellayani and coastal alluvium soils from the wet lands of the Integrated Farming System Research Station, Kerala Agricultural University, Karamana (8.4736 ⸰N; 76.914 ⸰E). The physical and chemical properties of respective soils revealed that, laterite soil was moderately acidic (pH 5.7) and coastal alluvium soil was strongly acidic (pH 5.2) in nature. The bulk density and particle density of the laterite soil was 1.60 and 2.65 Mg m-3and 1.36 and 2.57 Mg m-3 for coastal alluvium soil respectively. The electrical conductivity was 0.27 and 0.28 dS m-1 for laterite and coastal alluvium soil respectively. The cation exchange capacity of the soil was found to be 3.41 and 5.18 cmol (+) kg-1 for laterite and coastal alluvium soils respectively. The organic carbon was high in coastal alluvium soil (1.07 %) than laterite soil (0.63 %). The estimated major primary nutrient content was, available nitrogen (203 kg ha-1 and 338.69 kg ha-1); available phosphorus (21.7 kg ha-1and 14.48 kg ha-1); available potassium (228 kg ha-1and 121 kg ha-1) respectively. The secondary nutrients such as calcium, magnesium and sulphur were found to be 250, 42 and 43 ppm for laterite soil and 230, 132, 98 ppm for coastal alluvium soil respectively. A suitable method was validated for standardizing the analytical procedures for estimation of chlorantraniliprole residues in soil, plant, water, grains and straw by QuEChERS method and liquid-liquid partitioning using dichloromethane (DCM) in water. The residues were estimated and quantified by using LC-MS/MS and the method gave satisfactory recovery values of chlorantraniliprole for soil, water, and plant with good RSD (%) for recoveries. The analytical procedures gave good recovery for the chlorantraniliprole residues when spiked with 0.01, 0.05, 0.10, 0.5 and 1.0 levels and LOQ of chlorantraniliprole was determined as 0.01 mg kg-1. The recovery percentage ranged from 90.34 - 96.12 and 84.91 - 95.57 in laterite and coastal alluvium soils respectively. Similarly, the recovery percentage ranged from 97.72 - 99.75, 94.93 - 96.16, 88.97- 95.43 and 89.63- 95.43 respectively in water, plant, straw, and grains. The studies on persistence of chlorantraniliprole in laterite (S1) and coastal alluvium soils (S2) were performed under two different soil moisture conditions viz., field capacity (M1) and flooded (M2) by spiking (1, 2 and 4 mg kg-1) under laboratory conditions. The residues were estimated and quantified by using LCMS/ MS method. The half- life of chlorantraniliprole in the laterite soil when applied at 1, 2 and 4 mg kg-1 levels under the field capacity were 10.01, 15.67 and 21.16 days and the half- life 7.45, 10.25 and 12.69 days under flooded condition respectively. Similarly, the half- life of chlorantraniliprole in the coastal alluvium soil when applied at 1, 2 and 4 mg kg-1 levels were 13.84, 17.10 and 23.88 days under the field capacity and 9.18, 10.72 and 13.35 days under flooded condition respectively. The persistence was higher in coastal alluvium soil and degradation of chlorantraniliprole was faster at flooded condition than in field capacity condition for both the soils. Application of chlorantraniliprole at higher concentrations resulted in prolonged persistence compared to lower application levels. Mobility of chlorantraniliprole in laterite and coastal alluvium were assessed by analyzing the residue at different depths after loading 150μg of chlorantraniliprole followed by subsequent elution with 20ml, 40ml, 80ml and 160 ml of water equivalent to 50mm, 100mm, 200mm and 400mm rainfall. Majority of the residues were accumulated in 0- 5cm cross sections of the tube and presence of residues in lower layers were indicated by increasing the level of irrigation. The percentage of chlorantraniliprole residues in top 0 -5 cm in laterite soil was 63.73, 52.31, 31.48 and 27.77 and coastal alluvium was 73.46, 56.58, 34.48 and 25.70 on elution with 20ml, 40ml, 80ml and 160 ml of water respectively. Leaching potential was higher for laterite soil compared to coastal alluvium soil due to presence of low clay and organic matter content. Chlorantraniliprole residues were detected in leachate water for soil columns eluted with 160 ml of water for both the soils, whereas, the residues detected in leachate water was below limit of quantification (LOQ) in soil columns eluted with 20, 40 and 80 ml of water. Research data revealed that, type of soil, level of irrigation and depth of soil column influenced the mobility of chlorantraniliprole in soil The field experiment was conducted at the research fields of the Integrated Farming System Research Station, Karamana, Kerala Agricultural University. The study proposes to understand the probable side effects and residue accumulation in leaf, grains, and straw after the use of two different formulations of chlorantraniliprole viz., chlorantraniliprole 18.5 SC (Coragen ) and chlorantraniliprole 0.4 % G (Ferterra) each at 30 and 40 g a.i per ha, respectively in rice, the most important staple crop of Kerala, when applied to the treatment plots. The frequency of application was single - 25 days after transplanting (DAT), double (25 and 50 DAT) and triple (25, 50 and 75 DAT) applications. The persistence and dissipation pattern in soil and plant and the respective half-life values were calculated under field condition. The calculated half-life values of chlorantraniliprole for foliar (Coragen 18.5 SC) applications for T1 (single), T2 (double) and T3 (triple) were 6.93, 7.24, 8.9 days, respectively. Similarly, half-life for soil application of chlorantraniliprole (Ferterra 0.4 % G) T4 (single), T5 (double) and T6 (triple) were 7.63, 8.2, and 10.8 days respectively, in soil. The half-life values in plants were 9.15, 11.8 and 12.59 days for T3, T5 and T6, respectively. Chlorantraniliprole residues in straw and grains obtained from field study were also estimated. The residues detected in straw for treatments T3, T5 and T6 were 0.183, 0.076 and 0.282 mg kg-1 respectively. The residues in T1, T2 and T4 were found to be below the limit of quantification (LOQ). The residues in fresh grains and after parboiling were estimated and from which the extent of removal of residues was determined. The parboiling of grains was found to be an effective method of decontamination by higher dissipation of residues. In the case of grains, the initial residues detected in T3, T5 and T6 were 0.143, 0.283 and 0.382 mg kg-1 and on parboiling, this was reduced to 0.045, 0.106 and 0.159 mg kg-1 respectively. The per cent dissipation after parboiling were 68.53, 62.54 and 58.37 per cent for T3, T5 and T6, respectively. The studies on metabolism/ transformation products of chlorantraniliprole revealed that, no toxic metabolites were detected in soil or any plant parts. The soil enzyme activity tests were used as a measure of metabolic activity of micro-organisms in soil from field application. The residual effect of chlorantraniliprole formulations on soil microbes were also assessed indirectly using enzyme assays viz., dehydrogenase and urease activities in soil. The soil samples were collected from field experiment plot, at 0th, 15th, 30th, 45th and 60th day after application of chlorantraniliprole. In coastal alluvium soil, the dehydrogenase as well as urease activity was reduced due to the residual effect of chlorantraniliprole. Granular formulation (Ferterra 0.4 G) had more impact on activity of soil microbes, compared to foliar formulation (Coragen 18.5 SC). The frequency of application also influenced the soil microbial activity and the enzyme activities approached to control conditions by the 75th day after the last application for all the treatments except T6. Leachate study was conducted in tray by application of Ferterra 0.4 % G in two soils viz., laterite and coastal alluvium soil under cropped condition and collection of leachate water as well as soil for residue analysis. The dissipation pattern showed higher persistence of chlorantraniliprole in coastal alluvium soil than laterite soil, but residues detected in leachate water was more in laterite soil. In brief, laterite soils had higher dissipation potential than coastal alluvium soils. The persistence of chlorantraniliprole under field capacity condition was higher than flooded condition for both the soils. The mobility of chlorantraniliprole was found to be slightly higher in laterite soil compared to coastal alluvium soil and indicates its moderate mobility behavior. There exists a possibility of groundwater pollution with the application of higher concentration of chlorantraniliprole or due to heavy rainfall. The application of chlorantraniliprole formulations on crops in laterite soil may cause higher risk of groundwater contamination than coastal alluvium soils. The presence of higher amount of organic matter content in coastal alluvium soils is responsible for reducing the downward flow in soil profile to an extent. Field study revealed that, foliar application had lower residual effect than soil application of chlorantraniliprole. The frequency of application and type of formulation also affect the residual activity in soil and plants. Soil microbial activity was reduced initially but shifted to normal conditions within 60 days after application for single and double application, and by 75 days in the case of triple application of chlorantraniliprole (Ferterra 0.4 % G). The present findings may be used for modelling the environmental fate of chlorantraniliprole in laterite and coastal alluvium soils under different moisture levels and field conditions. The optimum use of chlorantraniliprole with recommended dosage on crops and soil along with field application of organic matter can prevent the ground water contamination significantly. Detailed study in undisturbed soil column is recommended in future studies to give better insight on leaching and mobility of chlorantraniliprole in soil.Item Sustainable rice production in Wayanad district: a tribal perspective(Department of Agricultural Extension, College of Agriculture, Vellayani, 2023-01-28) Shahlas Binth T; Anil Kumar AThe study on “Sustainable rice production in Wayanad district: A tribal perspective” was conducted during 2018 to 2021 with the objectives to study the perception of tribal farmers on the issues of sustainable rice farming and develop a sustainability index. Besides, study the livelihood status of tribal agricultural labourers based on gender analysis and attitude of tribal and non-tribal rice farmers towards the sustainability of rice farming. Three panchayats of Wayanad district, Thavinjal from Northern high hills (AEU 15), Panamaram from Wayanad central plateau (AEU 20) and Thirunelli from Wayanad eastern plateau (AEU 21) were selected as the locations for the study. Thirty tribal rice farmers and 30 non tribal rice farmers from the identified panchayats were randomly selected in consultation with the Krishi Bhavans concerned, amounting to 180 respondents. For the study on agricultural labourers, 20 male and 20 female tribal labourers each were randomly selected from the three identified panchayats thus amounting to a total of 120 respondents. A focus group comprising 30 members who were the officials and social activists representing the society were selected to identify, analyse and triangulate the social issues of rice farming. To conclude, identification of issues of sustainable rice production, its perception by tribal farmers and development of a sustainability index were relevant and important in the present socio-economic milieu of Wayanad district. Sustainability index for tribal rice farmers can be used as an effective tool to assess their social, economical and environmental sustainability and to formulate strategies for strengthening their overall sustainability at the community level. An attitude scale was developed for the study which provided insights into the attitude of tribal and non-tribal farmers towards the sustainability of rice farming by developing an attitude scale. Study on gender analysis of livelihood status among tribal agricultural labourers could bring out the real issues faced by women agricultural labourers who were forced to make decisions and borrow money due to lack of involvement of their male counterparts in family affairs.Item Medicinal properties and process optimisation for GABA enrichment in rice(Department of Community Science, College of Agriculture, Vellanikkara, 2023-12-15) Simla Thomas; Aneena, E RRice, the grain of life is consumed worldwide and serves as the cornerstone of global food security. Brown rice in its whole form contains various nutritive and bioactive components and has numerous health benefits. Germination is an effective method to enhance the organoleptic, textural and nutritional qualities of rice grains, including functional compounds such as gamma amino butyric acid (GABA). The present study revealed that, GABA content in rice can be enhanced by adopting optimum soaking and germination durations. In GABA enriched rice, the antioxidant, antiproliferative activities, nutritional benefits and sensory qualities were found to be higher than ungerminated rice. The developed processed rice products showed good sensory qualities and retained GABA content. Germination is an effective and low cost strategy to transform rice into a functional food.Item Bridging productivity loss in aerobic rice (Oryza sativa L.) through land configuration and intercropping(Department of Agronomy ,College of Agriculture,Vellayani, 2023-03-10) Shahana Begum.; Shalini Pillai, PItem Irrigation scheduling and water stress mitigation strategies in upland rice (Oryza sativa L.)(Department of Agronomy, College of Agriculture, Vellayani, 2021) Gritta Elizabeth Jolly; Sajitha Rani, TThe study entitled “Irrigation scheduling and water stress mitigation strategies in upland rice (Oryza sativa L.)” was carried out as two field experiments at the Instructional Farm, College of Agriculture, Vellayani from 2017 to 2020 to identify a suitable variety and irrigation method for upland rice, to standardize irrigation scheduling and to assess the effect of moisture stress mitigation strategies on the growth, yield and economics of upland rice. Experiment I entitled “Identification of suitable variety and standardization of irrigation method” was conducted from January 2019 to May 2019. The experiment was laid out in split plot design with five main plot treatments and two sub plot treatments, in four replications. The treatments included sprinkler irrigation at 100% PE, sprinkler irrigation at 75% PE, drip irrigation at 100% PE, drip irrigation at 75% PE and hose irrigation (farmer’s practice-irrigation given thrice in a week) as main plot treatments and rice varieties Uma and Prathyasa as sub-plot treatments. The height of the plant, number of tillers m -2 , leaf area index and dry matter production were observed to be significantly the highest for the variety Prathyasa irrigated using sprinkler irrigation at 100% PE and hose irrigation was significantly inferior to all other methods of irrigation. The variety Prathyasa irrigated using sprinkler irrigation at 100% PE also recorded the highest number of panicles m -2 (226.00), number of grains per panicle (159.75) and grain yield (4.37 Mg ha -1 ). The highest RLWC and consumptive use (434.25 mm) by the crop was observed in the variety Uma irrigated using sprinkler at 100% PE, followed by drip irrigated plots at 100% PE. The highest crop water use efficiency (1.53 kg m -3 ) was observed in the variety Prathyasa irrigated using hose method and the highest field water use efficiency (0.95 kg m -3 ) was observed in the variety Prathyasa irrigated using sprinkler at 100% PE. 282The economics of cultivation in terms of net returns ( ₹ 1,32,465.50 ha -1 ) and B:C ratio (2.67) were observed to be the highest in the variety Prathyasa irrigated using sprinkler irrigation plots at 100% PE, followed by the variety Prathyasa irrigated using drip irrigation at 100% PE. Field experiment II entitled “Standardization of irrigation scheduling and moisture stress mitigation strategies for upland rice” was conducted during January 2020 to April 2020. The experiment was laid out in split plot design with four main plot treatments and five sub plot treatments in five replications (the best treatment from the experiment I - sprinkler method of irrigation at 100% PE and the variety Prathyasa were used for the experiment II). The main plot treatments included approaches of scheduling irrigation: IW/CPE of 0.8, critical growth stage approach, irrigation to maintain soil moisture at 100% FC and irrigation to maintain soil moisture at 75% FC. The sub-plot treatments included field application of hydrogel polymer (20 kg ha -1 ), seed treatment with hydrogel polymer (10 g kg -1 ), hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @10g kg -1 ), foliar application of PPFM (1%) and absolute control. The plant height, number of tillers m -2 , leaf area index and dry matter production were observed to be significantly higher in the plots irrigated at 100% FC, treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @10 g kg -1 ), which was followed by the plots irrigated to maintain 2 cm depth of water at critical stages of crop growth. The number of days for 50% flowering, the number of panicles m -2 (233.20), length of panicle (20.36 cm), weight of panicle (3.07 g), number of grains panicle -1 (169.20), grain yield (5.00 Mg ha -1 ) and straw yield (8.07 Mg ha -1 ) were the highest in the plots irrigated at 100% FC and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @10g kg -1 . . The consumptive use by the crop was significantly the highest in the plots irrigated at 100% FC (1265.60 mm) and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 ).The crop water use efficiency recorded the highest value (0.69 kg m -3 ) in the plots irrigated at IW/CPE 283of 0.8 and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 ) and a significantly higher field water use efficiency (0.58) was recorded in the plots irrigated at IW/CPE of 0.8 and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 ) The highest B: C ratio (2.92) and net returns ( ₹ 1,58,000.00 ha -1 ) were obtained from the plots irrigated at 100% FC and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 . The results of the study revealed suitability of the variety Prathyasa, irrigated using sprinkler irrigation at 100% PE for higher yield and monetary returns under upland conditions. It also reflected the suitability of irrigating upland rice at 100 % FC as an effective approach of scheduling irrigation, along with the application of hydrogel polymer (field application @ 2.5kg ha -1 + seed treatment @ 10 g kg -1 ) as the most suitable moisture stress mitigation strategy for upland rice cultivation for enhanced yield and economic returns under water stress conditions.Item Physiological biochemical and molecular studies in medicinal rice (Oryza sativa L.) njavara as influenced by abiotic stresses(Department Of Plant physiology, College Of Agriculture, Vellayani, 2020) Wagh Yogesh Sahebrao; Viji, M MItem Biology and management of Sacciolepis interrupta (Wild.) stapf in rice(Department of Agronomy, College of Horticulture, Vellanikkara, 2020) Pujari Shobha Rani; Meera Menon, VItem Identification of molecular markers and quantitative trait loci(QTLs)associated with drought tolerant and plant production traits in rice(Oryza sativa L.)using association genetic analysis(Department Of Plant physiology, College Of Agriculture, Vellayani, 2020) Nithya, N; Beena, R