1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Seed invigouration and weed management for enhancing productivity in aerobic rice (Oryza sativa L.)(Department of Agronomy, College of Agriculture , Vellayani, 2025) Aswin Mohan; Sheeja, K RajThe experiment entitled “Seed inviguoration and weed management for enhancing productivity in aerobic rice (Oryza sativa L.) was conducted at College of Agriculture, Vellayani, Kerala during the period 2022-2024. The investigation pertaining to the study comprised two experiments. A pot culture experiment was conducted to assess the seed invigouration potential of liquid organic manures and field experiment to study the effect of seed invigouration and weed management regimes for higher productivity in aerobic rice. Pot culture experiment was conducted in September 2023 at the College of Agriculture, Vellayani. The experiment followed a completely randomized design (CRD) with 18 treatments in three replications. Treatments included beejamrit, jeevamrit, panchagavya, and vermiwash at 2.5 per cent, 3 per cent, 5 per cent, and 6 per cent concentrations, along with hydropriming and no priming. Seeds of Prathyasa variety were primed for 16 h and dried to original moisture before sowing. Seed priming with liquid organic manures significantly influenced seed germination parameters, seedling attributes, and vigor indices in rice. Among the treatments, beejamrit at 6 per cent concentration recorded higher germination percentage (90.0%), while beejamrit 5 per cent achieved the highest germination rate index (21.6). However, vermiwash 5 per cent proved superior in terms of overall germination performance, registering the highest germination index (125.3), greater speed of germination, and mean daily germination (2.1 no. d-1). In addition, the coefficient of rate of germination was higher in vermiwash 3 per cent (21.4). The shortest mean germination time (5.2 d) was observed with panchagavya 3 per cent. Beejamrit 6 per cent resulted in higher seedling vigor index I (3123) which was statistically on par with vermiwash at 3 per cent, 5 per cent, and 6 per cent, as well as panchagavya 5 per cent. In terms of seedling vigor index II, the higher value was observed with vermiwash 6 per cent (6.64), and was on par with vermiwash 5 per cent(6.49). Based on the total scores, seed priming with 5 per cent and 3 per cent vermiwash concentrations which scored the highest scores of 253 and 237, respectively, were selected for further evaluation under field condition The field experiment was conducted at the organic farm of Department of Agronomy from January to May 2024, in randomized block design (RBD) with three factors. The first factor was two levels of seed priming [vermiwash 3 per cent (p1) and vermiwash 5 per cent (p2)] and a control (unprimed seeds). The second factor consisted of various weed management regimes [wheel hoe weeding (WHW) performed three times at 15, 30, and 45 DAS (r1), live mulching with cowpea followed by WHW at 45 DAS (r2), Gliricidia maculata leaf mulching at 10 t ha-1 followed by WHW at 30 and 45 DAS (r3), hand weeding (HW) thrice at 15, 30, and 45 DAS (r4), and weedy check (r5)]. The Prathyasa variety of rice was used for the study. Seeds were sown using a seed drill, and cowpea seeds were sown for live mulching at 7 DAS of rice and was uprooted and spread at 45 DAS during wheel hoe weeding. Similarly, Gliricidia maculata leaf mulching was also done on 7 DAS. At 15, 45, and 60 DAS, the treatment combination p2r5 resulted in taller plants. However, at 30 DAS and harvest, p1r3 and p2r3 produced taller plants, respectively. Tillers m² were higher in p2r1 at 30 and 60 DAS, though it was on par with p2r3 at 30 DAS and p2r4 at 60 DAS. At 45 DAS, p2r4 produced a greater number of tillers m², and at harvest, p2r3 had a greater number of tillers m². Dry matter production per plant was found to be higher in p2r4 at 15 DAS, and at the remaining stages, p2r3 resulted in higher DMP per plant. The treatment combination p2r1 exhibited higher LAI at 30, 45, and 60 DAS. The chlorophyll content was higher in p2r1 at 15 DAS, p1r2 at 30 DAS, and in treatments p1r3, p2r1, p2r2 and p1r3 at 60 DAS. At 30 DAS - 45 DAS and 60 DAS - harvest, p2r3 resulted in higher crop growth rate (CGR) (4.74 g m² d⁻¹ and 11.96 g m² d⁻¹, respectively). However, at 45 DAS - 60 DAS, p3r3 exhibited the highest CGR (10.85 g m² d⁻¹). For 15 DAS - 30 DAS, p1r1 resulted in higher relative growth rate (RGR) (0.228 g g⁻¹ d⁻¹). However, at 45 DAS - 60 DAS, p3r3 resulted in significantly higher RGR (0.063 g g⁻¹ d⁻¹), and from 60 DAS - harvest, p1r5 showed the highest RGR (0.038 g g⁻¹ d⁻¹). The number of days to 50 per cent flowering ranged between 54 and 59 days across treatments, with the earliest flowering in seeds primed in p2r4 (vermiwash 5% + hand weeding thrice) (54 days). The treatment combination p2r2 had greater number of panicles m-2 (236 no. m-2) and 1000 grain weight, whereas, p2r4 had greater number of grains per panicle and p2r3 had higher panicle weight. The treatment combination, p2r3 resulted in significantly higher grain yield (2625 kg ha-1), straw yield and harvest index. Compared to p2r4 (unprimed seeds + hand weeding thrice), the percentage increase in grain yield observed in p3r3 (seeds primed in vermi wash 5 per cent concentration + G. maculata green leaf mulching with 10 t ha-1 fb WHW at 30 and 60 DAS) was 48.8 per cent. Weed infestation significantly reduced grain yield in aerobic rice. Among the treatment combinations, p3r5 recorded the highest weed index of 71.5 per cent. Among the quality parameters, the treatment combination, p3r1 resulted in higher starch content and was on par with all treatments except p1r1 and p3r4. At 15 DAS, p1r3 resulted in lower absolute density of BLW, however at 30 DAS, 45 DAS and 60 DAS, p2r4 registered lower absolute density of BLW. The absolute density of grasses was found to be lower in p2r2 and p3r5 at 15 DAS, p1r1 at 30 DAS, p2r1 at 45 DAS and p2r1 and p3r3 at 60 DAS. However, p1r3 resulted in lower total density of weeds at 15 DAS and p2r4 at the remaining stages. Weed dry weight was observed to be lower in p1r3 at 15 DAS and p2r4 at 30 DAS, 45 DAS and 60 DAS. Weed control efficiency also followed the same trend as that of weed dry matter. Nitrogen and P removal by weeds were observed to be lower in p2r4 at 30 DAS and 60 DAS. However, p2r4 showed lower K removal at 30 DAS and p3r4 at 60 DAS. The treatment combination, p2r2 resulted in higher N uptake by aerobic rice (72.6 kg ha-1) and it was followed by p2r3. However, p2r3 and p2r2 resulted in higher P uptake by aerobic rice (12.0 kg ha-1) and K uptake by p2r3 (48.4 kg ha-1). Interaction between seed priming and weed management regimes had significant effect only on organic carbon content and the treatment combination, p3r2 resulted in higher OC content (0.91%) and was on par with p2r3. Available P content of post experiment soil was found to higher in p2r2. The treatment combination, p2r3 resulted in higher gross return, net return (₹ 97070 ha-1) and B: C ratio (2.20) and it was followed by p2r2. The study demonstrated that seed priming with liquid organic manures— particularly vermiwash at 5 and 3 per cent concentrations—significantly enhanced germination, seedling vigour, and early growth parameters in rice. Both seed priming and weed management practices had a substantial impact on crop growth, physiological traits, nutrient uptake, yield, weed suppression, and economic returns. Among all treatments, seed priming with 5% vermiwash combined with green leaf manuring using Gliricidia maculata (10 t ha⁻¹), followed by wheel hoe weeding at 30 and 45 DAS, emerged as the most effective strategy for maximizing yield and profitability under aerobic rice cultivation.Item Conservation tillage and nano nitrogen nutrition in Chinese potato (Plectranthus rotundifolius (poir.) spreng.)(Department of Agronomy, College of Agriculture, Vellayani, 2024-04-27) Gopika, K T; Sheeba Rebecca IsaacThe study entitled "Conservation tillage and nano nitrogen nutrition in Chinese potato [Plectranthus rotundifolius (Poir.) Spreng]" was conducted at College of Agriculture, Vellayani during 2021-2023. The objective of the study was to assess the impact of conservation tillage and nano nitrogen nutrition on the growth, tuber yield and quality in Chinese potato, and carbon build up in the soil. The field experiment was executed during December 2022 to May 2023 at College of Agriculture, Vellayani. The experiment was laid out in split plot design with three methods of tillage [c1: Conventional tillage, c2: Reduced tillage (RT)+ surface incorporation of green manure (GM) cowpea and c3: RT+ surface retention of GM cowpea] as main plot treatments, and four N management practices [n1: 100% recommended dose of nitrogen (RDN) + nano urea, n2: 75% RDN+ nano urea, n3: 50% RDN+ nano urea and n4: 100% recommended dose of fertilizers (RDF)] as sub plot treatments, in three replications. In RT treatments, fodder cowpea variety Aiswarya was raised as green manure crop @ 20 kg seeds ha-1 and incorporated/ surface retained as mulch at flowering stage (45 DAS). Secondary ploughing in c2 and c3 plots was confined to the row zone alone. Cuttings of Chinese potato variety Suphala were planted at a spacing of 30 cm x 15 cm in all the plots. The NPK recommendation followed was 60: 60: 100 kg ha-1 (KAU, 2016). Nano urea (@ 0.4%) was sprayed 20 and 40 days after planting (DAP) as per treatments fixed. Other cultural operations were done in accordance with the KAU package recommendation for the crop. The treatment, c2 resulted in significantly taller plants at 90 and 120 DAP, higher number of branches per plant at 120 DAP and superior leaf area per plant at 30, 60 and 120 DAP. Among the subplot treatments, the significantly taller plants at 30 and 60 DAP, plant spread at 30, 60 and 90 DAP and number of branches at 30 DAP were recorded in n3. The treatment n1 recorded the highest leaf area at all the growth stages. Among the interactions, plants in c2n3 were significantly taller at 30 and 60 DAP, with the highest plant spread and leaf area at all stages of observation. The yield attributes and yield, number of tubers per plant (21.59), average tuber weight (12.13g) and marketable tuber yield (130.67 g per plant) were significantly the highest in c2. Tuber yield (16.20 t ha-1) was significantly higher in c3 and comparable with c2. In N management, n3 (50% RDN + nano urea) resulted in highest number of tubers and yield, and were the lowest in n4. Among the c x n interactions, c2n3 produced the highest tuber yield (17.74 t ha-1). Significantly higher chlorophyll contents were observed in c2 and was on par with c3. The chlorophyll content in n1 and n3 remained similar at 30 DAP and at 60 DAP, n1 was superior. The treatment combination c2n3 recorded the highest chlorophyll content at 60 DAP. Crop growth rate computed until 90 DAP, were significantly higher in c2 and during 90-120 DAP, in c3. It remained the highest in n1 upto 60 DAP and thereafter, n3 and n2 recorded the higher values. Leaf Area Index was higher in c2 but on par with c3. The highest LAI was recorded in c2n1 at all growth stages. No significant variations were found in days to start of senescence and biomass partitioning at the start of senescence due to tillage methods and interactions. Biomass accumulation followed the order tuber > stem > leaf, in all treatments. In tubers, significantly the highest biomass (66.4%) was recorded in n3. Nutrient uptake was higher for N and K in c2 and P uptake, in c3. With respect to N management, significantly higher N uptake was computed in n1 while P and K uptake were the highest in n3. Among interactions c2n3 was superior. Quality of tubers in terms of vitamin C and protein contents remained on par in c3 and c2 and among N management treatments, superior vitamin C content was observed in n3, and protein in n1. Starch content was the highest in n1 on par with n2. Among the treatment combinations, the highest starch and protein contents were observed in c2n1, and vitamin C in c2n3. The methods of tillage, N management and their interaction showed varied effects on soil nutrient status and were more pronounced for P, S and Zn. Conservation tillage methods (c2 and c3) elicited significant variations in soil C status. The highest TOC (11.80 g kg-1) and labile C (4.94 g kg-1) were recorded in c2 while non labile C (7.64 g kg-1) was the highest in c3. The C stock (5093 g m-2) was the highest in c3 and among interactions, c2n3 recorded the highest TOC. Soil microbial population and dehydrogenase activity were the highest in c2 and among c x n interactions, the combinations including c2 was superior. Economic analysis revealed c2n3 as the most profitable treatment combination for Chinese potato cultivation. The net income and BCR computed were ₹429657 ha-1 and 2.54 respectively. Based on the results of the study, in Chinese potato, the practice of raising GM cowpea sown @ 20 kg seeds ha-1, incorporation of biomass at flowering, planting stem cuttings in reduced tilled beds and nutrient management with 30 kg N (50% RDN), 60 kg P2O5, 100 kg K2O ha-1 + nano urea foliar spray (0.4%) at 20 DAP and 40 DAP, can be recommended as the most suitable conservation agriculture strategy. The C stock in soil was found to improve with conservation tillage practices.Item Performance of Maize (Zea mays L.) intercropping systems in lowlands(Department of Agronomy, College of Agriculture ,Vellayani, 2024-02-26) Meera, L Raj; Jacob JohnThe study entitled “Performance of maize (Zea mays L.) intercropping systems in lowlands” was undertaken at the College of Agriculture, Vellayani during 2021-2023. The objective was to evaluate different maize based intercropping systems in the summer fallow of double cropped lowland rice field in terms of weed dynamics, biological efficiency and economics. The field experiment was carried out at the Integrated Farming System Research Station (IFSRS), KAU, Karamana from January to May 2023 in Randomized Block Design with 10 treatments and three replications. The treatments comprised of T1: maize + bush cowpea (1:2), T2: maize + green gram (1:2), T3: maize + black gram (1:2), T4: maize + fodder cowpea (1:2), T5: sole crop of maize, T6: sole crop of bush cowpea, T7: sole crop of green gram, T8: sole crop of black gram, T9: sole crop of fodder cowpea and T10: fallow. Maize (var. TNAU maize hybrid Co-6) was raised as main crop and bush cowpea (var. PGCP-6), green gram (var.TM 96-2), black gram (var. VBN-6) and fodder cowpea (var. Aiswarya) were raised as intercrops. Maize was raised as per the recommendations of TNAU (CPG, 2005) and the intercrops as per KAU Package of Practice Recommendations (KAU, 2016). The results revealed that intercropping had significant effect on the growth and yield of the main crop and intercrops. Growth attributes of maize viz. plant height, number of leaves per plant, leaf area per plant and leaf area index (LAI) showed significant variation with intercropping. The treatment T5 resulted in taller plants, highest number of leaves per plant, leaf area per plant and LAI and it was followed by T1. Seed weight per cob (63.02 g), grain yield (4566 kg ha-1) and stover yield (13122 kg ha-1) were also highest in T5, which was followed by T3. Growth and yield attributes of intercrops were significantly reduced under intercropping systems. Sole crop of bush cowpea (T6), green gram (T7) and black gram (T8) recorded greatest plant height, number of branches per plant, leaf area per plant and LAI. Yield attributes like number of pods per plant, grain yield and haulm yield were also higher in sole cropping system. The plant height, number of branches per plant, leaf area per plant, leaf area index, leaf stem ratio, green fodder yield and dry fodder yield were higher in the sole crop of fodder cowpea (T9). Intercropping with maize profoundly reduced the weed count, weed dry matter production (DMP) and NPK removal by weeds. The lowest weed count was recorded in T9 at 30 DAS. At 60 DAS, lowest weed count was recorded in T3 and T1. The highest weed count was recorded in T10, both at 30 and 60 DAS. Lowest weed DMP was recorded in T1, 30 and 60 DAS. The weed smothering efficiency of maize + bush cowpea system was the highest among the different intercrops at 30 and 60 DAS (41.46 % and 59.04 % respectively). The N removal by weeds was lowest in T1(1.15 kg ha-1), which was on par with T4 (1.54 kg ha-1) at 30 DAS. At 60 DAS the lowest N removal was recorded in T1 (5.58 kg ha-1). P removal by weeds was lowest in T1 (0.62 kg ha-1, 0.64 kg ha-1) which was on par with T3 (1.78 kg ha-1,1.85 kg ha-1) both 30 DAS and 60 DAS respectively. K removal by weeds was lowest in T1 at 30 DAS (0.92 kg ha-1) and 60 DAS (2.22 kg ha-1). All the crops recorded higher values of NPK uptake under sole cropping of main crop and intercrops. The dehydrogenase activity was the highest in the maize + bush cowpea (T1) (175.52 µg TPF g-1 soil d-1) system compared to the others. The highest amount of available N in the soil found after the experiment was in T8 (472.29 kg ha-1) which was on par with T7 (397.23 kg ha-1) and T9 (397.23 kg ha-1). The highest amount of available P was found in T9 (71.00 kg ha-1) while available K was higher in T8 (168.64 kg ha-1). Analysis of the competitive indices of the intercropping system revealed that the land equivalent ratio (LER), monetary advantage index (MAI) and maize equivalent yield (MEY) were highest in the maize + black gram system (T3). The highest relative crowding coefficient and positive aggressivity value of maize indicated the dominance and competitive nature of maize over intercrops. The maize + black gram (T3) intercropping system recorded the highest net income (₹ 102262 ha-1) and B:C ratio (2.15). From the present study, it is inferred that in summer fallows of double cropped lowland, maize + black gram (1:2) system was more suitable in terms of maize equivalent yield, land equivalent ratio, monetary advantage index, net income and benefit cost ratio. Based on weed dry matter production, weed smothering efficiency and nutrient removal by weeds, the maize + bush cowpea (1:2) system was the best.Item Standardization of spacing and nitrogen management of multicut fodder sorghum(Sorghum bicolor x Sorghum sudanense)(Department of Agronomy,College of Agriculture , Vellayani, 2024-07-05) Bukke Sathish Kumar Naik; Usha, C ThomasThe study entitled “Standardization of spacing and nitrogen management of multicut fodder sorghum (Sorghum bicolor x Sorghum sudanense)” was undertaken at Instructional Farm, College of Agriculture, Vellayani, during 2021 to 2023. The key objective was to assess the influence of row to row spacing and nitrogen application on growth, yield, and quality aspects of multicut fodder sorghum. The field experiment was carried out at Instructional Farm, College of Agriculture, Vellayani, from November 2022 to August 2023. It was laid out in randomized block design with (3 x 3) + 1 treatments, replicated thrice. The treatment combinations included three levels each of row spacing (R) (r1- 20 cm, r2- 30 cm, r3- 40 cm) and nitrogen application (N) in seven equal splits (n1- 315 kg ha-1, n2- 245 kg ha-1, n3- 175 kg ha-1), compared against the control treatment (30 cm row spacing, nitrogen application- 315 kg ha-1 in seven equal splits, and MgSO4- 80 kg ha-1). Nitrogen was applied in seven splits- as basal, 20, and 40 days after sowing and after each cut. The variety used for the study was COFS-31, released from Tamil Nadu Agricultural University. A total of five cuts were taken during the study period. The treatment, r2 (30 cm row spacing) resulted in significantly taller plants with more leaves at harvest, the longest and broadest leaves, the highest leaf stem ratio, LAI at harvest, LAD, CGR, and RGR (at 30-60 DAS). The treatment, r3 (40 cm row spacing) resulted in the highest stem girth, and SLA (at harvest). Among the levels of nitrogen application, 315 kg N ha-1 (n1) recorded significantly taller plants with more leaves at harvest, the highest leaf length, leaf breadth, leaf stem ratio, stem girth, LAI, and SLA (at harvest), LAD, CGR, and RGR (at 30-60 DAS). Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in taller plants (235.78 cm), with the highest CGR (30-60 DAS). It resulted in a higher leaf stem ratio (0.55) and was on par with r3n1 (0.53). The treatment combination, r1n1 resulted in the highest LAI (6.19) at harvest. The treatment combination, r3n1 resulted in the highest SLA at harvest. The control treatment was superior over all the treatment combinations concerning growth attributes. The treatments, r2 (30 cm row spacing), and n1 (315 kg N ha-1) resulted in the highest total green fodder yield (148.09 t ha-1 and 159.87 t ha-1 respectively) and dry fodder yield (34.56 t ha-1 and 37.36 t ha-1 respectively). Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in the highest total green fodder yield (172.58 t ha-1) and dry fodder yield (40.60 t ha-1). The control treatment was superior over all the treatment combinations concerning green fodder yield (175.8 t ha-1) and dry fodder yield (41.52 t ha-1). The treatment, r2 (30 cm row spacing) significantly produced the highest chlorophyll content (1.94 mg g-1) at harvest. Among the levels of nitrogen application, 315 kg N ha-1 (n1) recorded significantly the highest chlorophyll content (1.95 mg g-1), and crude protein percent (9.03 %) at harvest. The control treatment did not show any significant influence on chlorophyll content and crude protein content over all the treatment combinations. The treatments, r2 (30 cm row spacing), and n1 (315 kg N ha-1) resulted in the highest NPK uptake. Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in the highest NPK uptake. The control treatment was superior to all the treatment combinations concerning NPK uptake. The treatment, r3 (40 cm row spacing) resulted in significantly the highest soil available P and K, higher soil available N, and Mg which were on par with the treatment r1 (20 cm row spacing). The treatment, n3 (175 kg N ha-1) resulted in the highest soil available P, K, and Mg, with higher soil available N, and was on par with the treatment n2 (245 kg N ha-1). Among the treatment combinations, r3n3 (40 cm row spacing + 175 kg N ha-1) resulted in the highest soil available P, K, and higher soil available N which was on par with the treatment combinations r1n1, r1n2, r3n2. Among the treatment combinations, r3n3 (40 cm row spacing + 175 kg N ha-1) resulted in higher soil available Mg which was on par with the treatment combinations r1n3, and r3n2. The treatments, r2 (30 cm row spacing), and n1 (315 kg N ha-1) resulted in the highest benefit cost ratio (2.09 and 2.23 respectively). Among the treatment combinations, r2n1 (30 cm row spacing + 315 kg N ha-1) resulted in a higher benefit cost ratio (2.52) which was comparable with r3n1 (2.32). The control treatment was superior over all the treatment combinations in terms of benefit cost ratio (2.77). Based on the study, it could be inferred that multicut fodder sorghum is suitable for cultivation in Kerala when grown at a row spacing (30 cm) and nitrogen dose of 315 kg ha-1 y-1 (seven equal splits) along with FYM- 10 t ha-1, P2O5- 40 kg ha-1 y-1, K2O- 40 kg ha-1 y-1, and MgSO4- 80 kg ha-1 y-1.Item Conservation tillage and nano nitrogen nutrition in Chinese potato (Plectranthus rotundifolius (poir.) spreng.)(Department of Agronomy, College of Agriculture, Vellayani, 2024-04-27) Gopika, K T; Sheeba Rebecca IsaacThe study entitled "Conservation tillage and nano nitrogen nutrition in Chinese potato [Plectranthus rotundifolius (Poir.) Spreng]" was conducted at College of Agriculture, Vellayani during 2021-2023. The objective of the study was to assess the impact of conservation tillage and nano nitrogen nutrition on the growth, tuber yield and quality in Chinese potato, and carbon build up in the soil. The field experiment was executed during December 2022 to May 2023 at College of Agriculture, Vellayani. The experiment was laid out in split plot design with three methods of tillage [c1: Conventional tillage, c2: Reduced tillage (RT)+ surface incorporation of green manure (GM) cowpea and c3: RT+ surface retention of GM cowpea] as main plot treatments, and four N management practices [n1: 100% recommended dose of nitrogen (RDN) + nano urea, n2: 75% RDN+ nano urea, n3: 50% RDN+ nano urea and n4: 100% recommended dose of fertilizers (RDF)] as sub plot treatments, in three replications. In RT treatments, fodder cowpea variety Aiswarya was raised as green manure crop @ 20 kg seeds ha-1 and incorporated/ surface retained as mulch at flowering stage (45 DAS). Secondary ploughing in c2 and c3 plots was confined to the row zone alone. Cuttings of Chinese potato variety Suphala were planted at a spacing of 30 cm x 15 cm in all the plots. The NPK recommendation followed was 60: 60: 100 kg ha-1 (KAU, 2016). Nano urea (@ 0.4%) was sprayed 20 and 40 days after planting (DAP) as per treatments fixed. Other cultural operations were done in accordance with the KAU package recommendation for the crop. The treatment, c2 resulted in significantly taller plants at 90 and 120 DAP, higher number of branches per plant at 120 DAP and superior leaf area per plant at 30, 60 and 120 DAP. Among the subplot treatments, the significantly taller plants at 30 and 60 DAP, plant spread at 30, 60 and 90 DAP and number of branches at 30 DAP were recorded in n3. The treatment n1 recorded the highest leaf area at all the growth stages. Among the interactions, plants in c2n3 were significantly taller at 30 and 60 DAP, with the highest plant spread and leaf area at all stages of observation. The yield attributes and yield, number of tubers per plant (21.59), average tuber weight (12.13g) and marketable tuber yield (130.67 g per plant) were significantly the highest in c2. Tuber yield (16.20 t ha-1) was significantly higher in c3 and comparable with c2. In N management, n3 (50% RDN + nano urea) resulted in highest number of tubers and yield, and were the lowest in n4. Among the c x n interactions, c2n3 produced the highest tuber yield (17.74 t ha-1). Significantly higher chlorophyll contents were observed in c2 and was on par with c3. The chlorophyll content in n1 and n3 remained similar at 30 DAP and at 60 DAP, n1 was superior. The treatment combination c2n3 recorded the highest chlorophyll content at 60 DAP. Crop growth rate computed until 90 DAP, were significantly higher in c2 and during 90-120 DAP, in c3. It remained the highest in n1 upto 60 DAP and thereafter, n3 and n2 recorded the higher values. Leaf Area Index was higher in c2 but on par with c3. The highest LAI was recorded in c2n1 at all growth stages. No significant variations were found in days to start of senescence and biomass partitioning at the start of senescence due to tillage methods and interactions. Biomass accumulation followed the order tuber > stem > leaf, in all treatments. In tubers, significantly the highest biomass (66.4%) was recorded in n3. Nutrient uptake was higher for N and K in c2 and P uptake, in c3. With respect to N management, significantly higher N uptake was computed in n1 while P and K uptake were the highest in n3. Among interactions c2n3 was superior. Quality of tubers in terms of vitamin C and protein contents remained on par in c3 and c2 and among N management treatments, superior vitamin C content was observed in n3, and protein in n1. Starch content was the highest in n1 on par with n2. Among the treatment combinations, the highest starch and protein contents were observed in c2n1, and vitamin C in c2n3. The methods of tillage, N management and their interaction showed varied effects on soil nutrient status and were more pronounced for P, S and Zn. Conservation tillage methods (c2 and c3) elicited significant variations in soil C status. The highest TOC (11.80 g kg-1) and labile C (4.94 g kg-1) were recorded in c2 while non labile C (7.64 g kg-1) was the highest in c3. The C stock (5093 g m-2) was the highest in c3 and among interactions, c2n3 recorded the highest TOC. Soil microbial population and dehydrogenase activity were the highest in c2 and among c x n interactions, the combinations including c2 was superior. Economic analysis revealed c2n3 as the most profitable treatment combination for Chinese potato cultivation. The net income and BCR computed were ₹429657 ha-1 and 2.54 respectively. Based on the results of the study, in Chinese potato, the practice of raising GM cowpea sown @ 20 kg seeds ha-1, incorporation of biomass at flowering, planting stem cuttings in reduced tilled beds and nutrient management with 30 kg N (50% RDN), 60 kg P2O5, 100 kg K2O ha-1 + nano urea foliar spray (0.4%) at 20 DAP and 40 DAP, can be recommended as the most suitable conservation agriculture strategy. The C stock in soil was found to improve with conservation tillage practices.Item Management of submerged aquatic weeds by pond liming(Department of Agronomy, College of Agriculture, Vellanikkara, 2024-04-15) Sajjana Gandla GowthamThe aquatic weed infestations are proliferating at an alarming rate resulting in various adverse effects such as the water quality degradation, water flow disruption, reduced water storage capacity, and the establishment of habitats for vectors. Though physical or mechanical measures can be adopted for their control, it is not feasible due to practical difficulty or cost and drudgery involved. There is no registered herbicide for effectively managing aquatic macrophytes. Hence, a study entitled “Management of submerged aquatic weeds by pond liming” was conducted at the Department of Agronomy, College of Agriculture, Vellanikkara, Kerala Agricultural University, during 2022-23. The objective was to assess the efficiency of different liming materials against three common submerged aquatic weeds (Cabomba furcata, Lymnophila heterophylla, and Hydrilla verticillata), and its effects on water and sediment quality. The impact of different liming doses on phytotoxicity, chlorophyll degradation, water, and sediment quality over time was analysed through ANOVA, and the significant differences between treatments were studied using TUKEY's test. Correlation and regression studies on percentage control, phytotoxicity, chlorophyll degradation, water, and sediment quality were conducted to elucidate the trends over time. The experiment consisted of three tank studies and one field study. The tank studies were conducted to standardize the doses of various liming materials. The treatments in the first tank study were three different liming materials (calcite, quicklime, and dolomite) at varying doses of 50, 100, 200, 400, and 600 mg L-1. As these doses were found ineffective, in the second tank study, treatments included higher concentrations (0.8, 1.0, 1.2, and 1.4 g L-1) of calcite, quicklime, and dolomite. Only CaO was found effective in the second tank study. Hence varied doses of CaO @ 2, 4, 6, 8, and 10 g L-1 were included in the third tank study and higher doses were found more effective. In field study, varying doses of quicklime @ 2, 4, and 6 g L-1 was tested in lined irrigation channels of Kole lands infested with limnophila during May 2023.The total quantity of CaO to be applied was arrived at based on quantity of water in the waterbody. From the first and second tank studies, it was revealed that, calcite and dolomite were not effective in controlling the weeds whereas quicklime at 1.0 g L 1 and above was effective. However, there was a noticeable influence on pH and EC of water when calcite and dolomite was used. Conversely, the higher dose of quicklime resulted in considerable effect on both water and sediment quality. From the third experiment, the efficacy of quicklime on weeds was evident across all liming doses (2, 4, 6, 8, and 10 g L-1). Notable impacts on chlorophyll content and phytotoxicity were observed from 7 days after application. More than 50 per cent reduction in chlorophyll content was noted at higher doses after 14 days of liming. By 21 days, a substantial decrease from 0.98 mg g-1 to 0.07 mg g-1 was observed in cabomba and from 1.65 mg g-1 to 0.07 mg g-1 in hydrilla, achieving 85 per cent control. Similarly, in limnophila, chlorophyll content reduced from 0.83 mg g-1 to 0.15 mg g-1 with a 75 per cent control. In the field experiment, when applied in lined channels, quicklime applied @ 6 g L-1 of water in the channel resulted in complete weed control (100 %), while 4 g L-1 resulted in 50 per cent control only. The water quality parameters like pH, EC, carbonates, bicarbonates, alkalinity, total hardness, calcium, and Chemical Oxygen Demand (COD) were positively correlated with increasing doses of quicklime. However, all parameters except COD were in the acceptable range by 30 days after liming. pH values were in the range of 9.27-9.71 by 30 days at higher doses. Alkalinity, total hardness, carbonates, bicarbonates, and calcium increased by 15 days after application and thereby, a slight reduction was observed. Bicarbonates ranged from 2.83 meq L-1 to 9.0 meq L-1. Alkalinity was within the permissible limit (600 mg L-1) and ranged from 53.33 mg L-1 to 266.66 mg L-1 in treated tanks. In all the treatments COD was above the acceptable limit of 1 mg L-1. By 30 days after liming, nutrient content in both water and sediment parameters showed a negative correlation with the increasing dose of quicklime. In field study pH was within a narrow range of 6.47 to 6.87 by 21 days. The pH, EC, organic carbon, and calcium content of sediment were positively correlated with doses of quicklime. Whereas the available N, P, K, magnesium, iron, and manganese were negatively correlated. Organic carbon content linearly increased with increasing quicklime concentration in all the treatments and was in the medium range (0.50 % to 0.75 %). The current study revealed that the quicklime can effectively control submerged aquatic weeds with no regrowth. In tank study, chlorophyll degradation progressed with time and complete chlorophyll degradation was observed by 21 days after liming in higher doses starting from 6 g L-1 and by 30 days complete control was observed even at lower doses. However, in the field study, the lower doses of 2 and 4 g L-1 were less effective and the higher dose of 6 g L-1 resulted in complete chlorophyll degradation and death of weeds by 21 days. When quicklime was applied, there was an immediate hike in water quality parameters and over time, followed by a gradual decline and reached the acceptable range by 21 days after liming. Similarly, no adverse effects on aquatic fauna such as fishes and snails were observed. Hence, the study indicates the possibility of CaO application as an eco friendly and effective means for managing submerged freshwater aquatic weeds. However, the size and nature of the waterbody, weed density and volume of water contained are the three important factors which decides the practical feasibility of the technology. The present technology has to be extended to ponds and crop lands for a comprehensive investigation and validation of its effectiveness in managing submerged aquatic weeds and algae.Item Integrated weed management in foxtail millet [Setaria italica(L.)P. Beauv.](Department of Agronomy, College of Agriculture,Vellanikkara, 2025) Shafna, P H.; Syama, S MenonMillets serve as a vital staple food in Asia and Africa, ensuring food security and nutrition. Millet cultivation is found to be increasing due to its climate resilience and nutraceutical importance. Foxtail millet (Setaria italica (L.) P. Beauv) locally known as thenai, is one of the oldest cultivated millets in India. However, millets also face challenges from weeds, especially in rainfed conditions, causing drastic yield reduction. The present study entitled “Integrated weed management in foxtail millet [Setaria italica (L.) P. Beauv.]” was carried out at the Department of Agronomy, College of Agriculture, Vellanikkara, from January 2024 to April 2024. The objective of the experiment was to develop economically viable integrated weed management practices for foxtail millet. The experiment was laid out in a randomized block design with eight treatments and three replications. The variety used for the experiment was DHFT-109-3, released from UAS, Dharwad. The crop was sown at a spacing of 30 cm x 10cm. The eight treatments were T1- stale seedbed technique, T2- straw mulching in the interspaces, T3 – pre-emergence application of oxyfluorfen @ 0.10 kg/ha (at 0-3 DAS) followed by hand weeding at 25-30 DAS, T4 - pre-emergence application of pretilachlor 30% + pyrazosulfuron ethyl 0.75% WG (premix) @ 0.10 kg/ha (at 0-3 DAS) followed by hand weeding at 25-30 DAS, T5 - Live mulching with green gram @25 kg ha-1, T6 - Brown manuring with green gram @ 25 kg ha-1, T7 - Handweeding at 25 and 45 DAS, T8 - Unweeded control. In the stale seedbed technique, after land preparation, weeds were allowed to germinate for 15 days before sowing the crop, and the emerged weeds were destroyed using non-selective herbicide glufosinate ammonium @ 0.5 kg ha-1. In straw mulching (T2), rice straw (@ 5t ha-1) was spread in the interspaces of the crop to prevent weed germination. In live mulching(T5), green gram grown in the interspaces of the crop was uprooted at 15 DAS and spread in between rows. Similarly in brown manuring, 2,4-D @ 0.5 kg ha-1 was sprayed 15 days after the establishment of green gram. Weed management had no significant effect on plant height within the treatments throughout the crop growth period. The number of tillers and productive tillers was higher in weed managed plots compared to unweeded control, and all the tillers were found to be productive irrespective of the treatments. The highest grain yield (1655 kg ha-1) was recorded in hand-weeded control, which was followed by straw mulching in the interspaces (1516 kg ha-1). The highest straw yield (3620 kg ha-1) was obtained from hand-weeded control, which was on par with straw mulching in the interspaces (3466 kg ha-1). Hand-weeded control (5275kg ha-1) resulted in higher drymatter production, and it was followed by straw mulching in the interspaces (4983 kg ha-1). Hand weeding twice at 25 and 45 DAS reduced the weed density and weed dry matter which in turn increased the yield. Straw mulching in the interspaces of foxtail millet increased the moisture availability to crop and weed suppression due to the unavailability of sunlight, which ensured healthy growth of the crop and ultimately enhanced grain production. High soil moisture, smaller grain size, and selective nature of the pre-emergence herbicides (oxyfluorfen and pretilachlor +pyrazosulfuron ethyl) resulted in phytotoxicity causing 66 per cent reduction in foxtail millet population though they were effective in weed control. Weed density and weed dry matter accumulation at 15 DAS were lowest in herbicide-applied treatments (T3 and T4), while unweeded control and hand weeding showed higher values. At 25 DAS, hand weeding twice at 25 and 45 DAS showed lower weed density and weed dry weight, and it was statistically on par with herbicide applied treatments (T3 and T4), followed by straw mulching (T2). At 45 and 75 DAS, hand weeding twice (at 25 and 45 DAS) recorded as the lowest weed dry weight and highest weed control efficiency, followed by herbicide-applied treatments (T3 and T4). There were no significant differences among treatments with respect to soil physiochemical properties after the experiment. The highest net returns and B: C ratio were realized in treatment brown manuring with green gram (Rs. 17330/- and 1.26 respectively) followed by straw mulching in interspaces (Rs. 11930/- and 1.17 respectively). Increased net returns and benefit-cost (B: C) ratio obtained from brown manuring with green gram can be due to the reduced labour cost compared to other treatments, and it was lower in straw mulching due to the increased cost of straw. Eventhough hand weeding at 25 and 45 DAS was found to be the best and efficient method of weed control in foxtail millet, it is economically not feasible. Straw mulching in the interspaces of foxtail millet was economically effective for summer rice fallows in terms of easiness in straw availability as well as soil moisture conservation. Pre-emergence application of herbicides (oxyfluorfen, pretilachlor + pyrazosulfuron ethyl) is not suitable for weed management in direct sown foxtail millet due to the small grain size of crop and non-selective action of the herbicides, which inhibited the germination of the crop along with weed seeds.Item Weed management in semi-dry rice of semi-dry rice Onattukara sandy plains(Department of Agronomy, College of Agriculture, Vellayani, 2024-03-14) Rachana, V R; Jacob, DThe study entitled “Weed management in semi-dry rice of Onattukara Sandy Plains” was conducted at College of Agriculture, Vellayani during 2021-2023. The objective of the study was evaluation of ready-mix pre-emergence and post-emergence herbicides for weed management and their effect on growth and yield of semi-dry rice in Onattukara region. The field experiment was carried out in farmer’s field at Onattukara Sandy Plains (AEU 3) during kharif season 2023. The experiment was laid out in RBD with eight treatments and three replications. The treatments comprised pre-emergence (PE) pendimethalin + pyrazosulfuron ethyl 787 g ha-1 followed by (fb) post-emergence (PoE) triafamone + ethoxysulfuron 60 g ha-1 (T1), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb PoE penoxsulam + cyhalofop butyl 135 g ha-1 (T2), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb PoE bispyribac sodium 25 g ha-1 (T3), PE pendimethalin + pyrazosulfuron ethyl 787 g ha-1 fb mechanical weeding at 25 DAS (T4), PE pendimethalin 770 g ha-1 fb mechanical weeding at 25 DAS (T5), mechanical weeding twice at 15 and 30 DAS (T6), hand weeding twice at 15 and 30 DAS (T7), and weedy check (T8). Ready-mix formulations of pendimethalin + pyrazosulfuron ethyl, triafamone + ethoxysulfuron and penoxsulam + cyhalofop butyl were used in the study. Pre-emergence herbicides were applied on the next day after sowing and post emergence herbicides were applied at 25 DAS. Mechanical weeding was done with wheel hoe weeder. The short duration rice variety ‘Bhagya’ was used in the study. Weed management practices significantly influenced the growth parametres such as plant height, number of tillers per square metre, and dry matter per hill. In comparison to other weed management treatments, treatments (T1, T2, T3, and T4) that recieved PE pendimethalin + pyrazosulfuron ethyl had taller plants and more tillers per square metre at 20 DAS. PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) recorded significantly higher plant height (64, 92, and 106 cm), more number of tillers per square metre (486, 552, and 515) and dry matter production per hill (8.08, 14.47, and 17.70 g) at 40 DAS, 60 DAS and harvest. 98 Leaf area index (LAI) was higher in T1, T2, T3, and T4 at 20 DAS. Treatment T2 resulted in higher LAI at 40 DAS (3.27) and 60 DAS (6.23). Crop growth rate (CGR) observed in T2 during 20-40 DAS (18.20 g m-2 d-1) was higher and showed an increase during 40-60 DAS (21.29 g m-2 d-1). Relative growth rate (RGR) was higher in T2 during 20-40 DAS (0.057 g g-1 d-1) than T1, T3, T4, T5, and T6. During 40-60 DAS, RGR in T2 was comparable. Weed management practices significantly influenced the yield attributes of rice. Treatment T2 resulted in higher number of productive tillers per square metre (462), greater number of spikelets (120) and filled grains per panicle (108), heavier grains per panicle (3.09 g), and the lowest sterility percentage (10.40 %). The combination of PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) resulted in significant increase in grain yield (4960 kg ha-1), straw yield (6175 kg ha-1), and harvest index (0.45). Compared to treatment T7 (hand weeded twice at 15 DAS and 30 DAS) treatment T2 exhibited about a 40 per cent increase in grain yield. Treatment T2 had the lowest weed index (0.00 %), followed by T1 (7.63 %). Highest weed index in weedy check indicated that presence of weed resulted in 56.32 % yield reduction. Treatment T2 had the lowest weed index (0.00 %), followed by T1 (7.63 %). Highest weed index in weedy check indicated that presence of weed resulted in 56.32 % yield reduction. The major weed species observed in the experimental field were categorised in to grasses, sedges and broad leaf weeds. Oryza sativa f. spontanea, Isachne miliacea Roth ex Roem et Schult, Eleusine indica (L.) Gaertn, Echinochloa colona L., Sacciolepis interrupta (Wild). Stapf, and Paspalum distichum L. were the major grasses. Cyperus iria L., Cyperus difformis L., and Fimbristylis miliacea (L.) Vahl were the major sedges. Ludwigia perennis L., Melochia corchorifolia L., Marsilea quadrifolia L. and Monochoria vaginalis (Burm. f.) C. Presl ex Kunth were the major broad leaf weeds observed in the experimental field. Weed management practices significantly reduced the absolute density of weeds. The treatments T1, T2, T3, and T4 exhibited lower absolute densities of grasses, sedges, and broad leaf weeds at 20 DAS. Whereas, T2 resulted in lower absolute density at 40 99 DAS and 60 DAS. At 40 DAS, the relative densities of grasses (34.95%), sedges (33.73%), and broad-leaf weeds (31.21%) in T2 indicating a larger proportion of grasses in total weed population. Compared to other treatments, T2 significantly lowered weed dry weight at 40 DAS (14.68 g m-2) and 60 DAS (26.14 g m-2) which resulted in higher weed control efficiency of 82.83 %, and 80.77 % at 40 DAS and 60 DAS. The treatment T2 resulted in higher nitrogen (140 kg ha-1) uptake by crop at harvest and it was on par with T1. The phosphorus uptake was highest in T2 (34 kg ha 1). The higher potassium (118 kg ha-1) uptake was recorded in treatment T2 and was comparable with T1, T3 and T4. The treatment T2 recorded lower weed removal of N, P, and K at 40 DAS and 60 DAS. The post-experimental soil available NPK were also observed to be higher in T2. The soil enzyme activity was significantly influenced by weed management treatments. Among the treatments, T2 recorded higher dehydrogenase activity at 40 DAS and 60 DAS. Urease activity at 40 DAS and 60 DAS were higher in T2 and was comparable with T1 and T3. Considering the treatments, PE pendimethalin + pyrazosulfuron ethyl fb PoE penoxsulam + cyhalofop butyl (T2) resulted in highest gross income (₹ 204488 ha-1), net income (₹ 58943 ha-1) and Benefit: Cost ratio (1.41). It could be concluded from the study that, the pre-emergence application of ready-mix pendimethalin + pyrazosulfuron ethyl 787 g ha-1 at 0-3 DAS followed by post emergence application of ready-mix penoxsulam + cyhalofop butyl 135 g ha-1 at 25 DAS can be recommended as a cost-effective weed management practice for better weed control, higher yield and net income in semi-dry rice at Onattukara Sandy Plains.Item Irrigation and crop establishment techniques in Bajra Napier hybrid(Department of Agronomy, College of Agriculture, Vellayani, 2025-07-23) Greeshma, U; Usha C ThomasThe research entitled “Irrigation and crop establishment techniques in Bajra Napier hybrid” was conducted at Department of Agronomy, College of Agriculture, Vellayani, during 2022 to 2025. The major objectives of the study were standardization of irrigation levels for popular Bajra Napier hybrid varieties in Kerala and standardization of sett size, age and method of planting of Bajra Napier hybrid. The study was undertaken as two separate parts. Part 1 entitled “Standardization of irrigation levels for popular Bajra Napier hybrid varieties in Kerala” was conducted from March 2023 to August 2024 at Instructional Farm, College of Agriculture, Vellayani. The experiment was laid out in split plot design with 4 main plots (i1 - IW/CPE- 1.00, i2 - IW/CPE- 0.80, i3 - IW/CPE- 0.60 and i4 - Rainfed), 3 sub plots (v1 – Susthira, v2 – Suguna and v3 – CO-5) and three replications. Crop was irrigated to a depth of 2.5 cm. Initial 6 months was taken as establishment period and after that, observations were recorded for 12 months. The results revealed that irrigation scheduling at IW/CPE ratio of 1.0 significantly enhanced the growth attributes including mean plant height, number of tillers per hill, leaf stem ratio (1.85), leaf area, and leaf area index compared to lower irrigation levels. Among the varieties, CO-5 consistently recorded superior growth performance, achieving the highest mean plant height (208.07 cm), leaf stem ratio (1.69), leaf area (228.87 cm²), and leaf area index (12.13). The mean number of tillers per hill was the highest in Suguna (v2). Among the interactions, CO-5 irrigated at an IW/CPE of 1.0 (i1v3) yielded the highest growth values like mean leaf stem ratio, leaf area and leaf area index. The results on yield revealed that total green and dry fodder yield were the highest in irrigation at an IW/CPE of 1.0 (175.45 t ha-1 and 40.95 t ha-1, respectively). Variety CO-5 (v3) produced the highest total green fodder (186.74 t ha-1) and dry fodder yield (39.05 t ha-1). Among the treatment combinations, i2v3 (CO-5 at an IW/CPE of 0.8) recorded the higher total green fodder (206.06 t ha⁻¹) and dry fodder (51.26 t ha⁻¹) yield, and remained comparable with i1v3. Across all harvests, green fodder yield and dry fodder yield followed a declining trend from the first to the fifth cut, with consistently higher yields recorded under IW/CPE of 1.0 and CO-5 variety at each harvest. Root studies revealed that rainfed conditions encouraged deeper rooting (46.56 cm), whereas irrigation at IW/CPE 1.0 improved root biomass (318.83 g per plant), with CO-5 exhibiting superior root dry weight (389.08 g per plant). Among the interactions, the treatment combination of rainfed irrigation with variety CO-5 (i4v3) recorded the deepest roots (51.73 cm). Conversely, the highest root dry weight (503.83 g per plant) was recorded in the combination of IW/CPE 1.0 with CO-5 (i1v3). Biochemical analysis showed significantly higher chlorophyll content in treatments involving IW/CPE 1.0 and CO-5, although crude protein content remained unaffected by treatments. Lower crude fibre content was noticed in IW/CPE of 0.8 (29.91%) and was on on par with i1. Crude protein yield was the highest in i1v3 (IW/CPE of 1.0 in CO-5) recording the maximum crude protein yield of 4739 kg ha⁻¹, which was statistically on par with i2v3. Analysis of post-experiment soil showed no significant effect for interactions in soil pH, electrical conductivity, organic carbon and available N. However, available phosphorus was the highest under rainfed conditions (i4). Interaction between irrigation levels and varieties also influenced soil potassium status, with i1v3 (IW/CPE of 1.0 x CO-5 variety) recording the highest value. Nutrient uptake studies revealed that nitrogen, phosphorus, and potassium uptake closely followed the same trend as that of dry fodder yield, with the highest uptake under IW/CPE of 1.0 and in the variety CO-5, particularly in the treatment combination i1v3 (CO-5 at an IW/CPE of 1.0). The water use efficiency and economic water productivity was found to be higher in irrigation scheduling at IW/CPE ratio of 0.8 (45.67 kg ha-1 mm-1 and 161.55 ₹ ha-1 mm-1) and it was on par with IW/CPE ratio 1.0. Among varieties, CO-5 recorded higher WUE and economic water productivity. CO-5 irrigated at an IW/CPE of 0.8 recorded higher WUE and the highest economic water productivity. Economic analysis showed that CO-5 irrigated at an IW/CPE of 0.8 (i2v3) achieved the highest net returns (348655 ₹ ha-1) and B: C ratio (1.94). The part II of the study for “standardization of crop establishment methods in Bajra Napier hybrid” was conducted from June to October 2023 and the confirmatory trial was conducted from June – October 2024 at Instructional Farm, College of Agriculture, Vellayani. The experiment was laid out in randomized block design with 3 factors and at three levels each, replicated thrice. The treatments comprised three levels of nodes per cutting (n1 – Single noded cutting, n2 – Two noded cutting, n3 – Three noded cutting), three planting method (p1 – Horizontal planting, p2 - Vertical planting, p3 – Planting at 45 degree) and three stages of maturity (s1 – 3 months, s2 – 4 months, s3 – 5 months). The observations were recorded to two harvests and the variety used for the study was Susthira. The results revealed that growth, yield, establishment, and economics were significantly influenced by nodes per cutting, planting methods, stage of maturity and their interactions. Among the nodes per cutting, three noded cutting (n3) recorded tallest plants (170.93 and 227.72 cm respectively), mean number of tillers per hill (8.92 and 8.32 respectively), leaf stem ratio, leaf area, LAI (8.07 and 8.54 respectively), total green fodder yield (88.49 and 85.27 t ha-1 respectively) and total dry fodder yield (22.12 and 21.32 t ha-1 respectively) in first and second year. But the specific leaf area was the highest in single noded cutting (n1). Among the planting methods, horizontal planting (p1) recorded the highest mean number of tillers per hill, leaf stem ratio, LAI, mean specific leaf area, total green fodder yield (92.78 and 90.84 t ha-1 respectively), total dry fodder yield (23.19 and 22.71 t ha-1 respectively) and crude protein yield (2032 and 2131 kg ha-1 respectively) in first and second year. Among the stages of maturity, cuttings from 4 month old plants (s2) recorded the highest number of tillers per hill, leaf stem ratio, LAI, total green (85.91 and 86.30 t ha-1 respectively) and dry fodder yield (21.48 and 21.57 t ha-1 respectively) and crude protein yield (1892 and 2034 t ha-1 respectively) in first and second year. The lowest number of days for first harvest (75 days in both years) was observed in 4 month old cutting (s2). Horizontal planting of three noded cutting taken from 4 month old plants (n3p1s2) recorded the highest mean number of tillers per hill, mean leaf stem ratio, mean LAI, total green (156.46 and 155.80 t ha-1 respectively) and dry fodder yield (39.12 and 38.95 t ha-1 respectively) and crude protein yield in both years. Among the establishment characters, 4 month old cutting (s2) established earlier (10.33 and 10.52 respectively) in both years. The treatment combination n3p1s2 (horizontal planting of three noded cutting taken from 4 month old plants) recorded higher establishment percentage in first and second year. The economic analysis revealed that, horizontal planting of three noded cutting taken from 4 month old plants (n3p1s2) recorded the highest B: C ratio in first (3.91) and second (3.89) year. It could be concluded that, among the Bajra Napier hybrid screened, the variety CO-5 irrigated at an IW/CPE of 0.8 could be recommended for realizing higher green fodder yield, dry fodder yield, WUE, economic water productivity, net returns and B:C ratio. In Bajra Napier hybrid variety Susthira, horizontal planting of three noded cutting taken from 4 month old plants could be adjudged as the best establishment method for higher growth, yield, establishment and B:C ratio.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.