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ThesisItem Open Access Response of sweet potato [Ipomoea batatas (L.) Lam.] to secondary nutrients(Department of Agronomy, College of Horticulture, Vellanikkara, 2020) Nengparmoi, TH; KAU; Prameela, PSweet potato is an important food crop with short duration and high nutrient requirement. As the deficiency of secondary nutrients is generally encountered in highly leached acid soils of Kerala and the research on supplementation of these nutrients in enhancing the productivity of sweet potato is limited, the present study entitled “Response of sweet potato [Ipomoea batatas (L.) Lam.] to secondary nutrients” was carried out. The objective was to assess the influence of secondary nutrients on growth, yield and quality of sweetpotato. The experiment was conducted from September 2019 to January 2020 at Agronomy Farm, College of Horticulture, Vellanikkara, Thrissur. The experiment was laid out in RBD with 11 treatments replicated thrice. The treatments included five levels of magnesium sulphate i.e., 0, 40, 60, 80 and 100 kg/ha along with N: P2O5 : K2O @ 75:50:75 kg/ha (KAU POP) and N : P2O5 : K2O @ 65:12:20 (soil test based). A high yielding sweet potato variety ‘Sree Kanaka’ was used. Growth parameters like vine length, leaf area, and total dry matter accumulation per plant were significantly influenced by nutrient management. Higher doses of N: P2O5 : K2O (75:50:75) irrespective of MgSO4 dose (0 to 100 kg/ha) showed higher values for these parameters compared to treatments receiving lower doses of N : P2O5 : K2O (65:12:20) along with MgSO4. At 30 days after planting (DAP), vine length ranged from 40.5 cm to 55.6 cm and it increased to 2.5m by 90 DAP. At this stage, all the treatments exhibited comparable vine length irrespective of nutrient doses, except T3 (65:12:20 + MgSO4 @ 60 kg/ha) and T7 (75:50:75 + MgSO4 @ 40 kg/ha) which registered higher values and differed significantly from others. Higher and comparable total dry matter accumulation was also observed in treatments where N : P2O5 : K2O @ 75:50:75 along with varying doses of MgSO4 was applied. The highest leaf area index of 3.48 was noticed in treatment T8 which received N : P2O5 : K2O (75:50:75) with MgSO4 @ 60 kg/ha and the lowest was seen in organic management (T11). Chlorophyll content at 60 DAP was not significantly influenced by varied doses of nutrients applied. Marketable tuber yield ranged from 19.8 to 35.9 t/ha and the treatments T7 (75:50:75 + MgSO4 @ 40 kg/ha) (35.9 t/ha) and T11 (organic management) (32.2 t/ha) resulted in higher tuber yields and were on par. Application of lower dose of N: P2O5: K2O based on soil test values resulted in lower yields compared to recommended dose. The highest harvest index of 0.72 was observed in T11 (Organic management) followed by T7 (0.60). Unmarketable tuber yield ranged from 1.0 to 1.7 t/ha. Higher and comparable unmarketable yield was observed in treatments T2 (65:12:20 + MgSO4 @ 40 kg/ha) and T3 (65:12:20 + MgSO4 @ 60 kg/ha) which received lower doses of N : P2O5 : K2O and MgSO4 and registered lower marketable yield. The unmarketable yield was the lowest in superior treatment T7 (75:50:75 + MgSO4 @ 40 kg/ha). Quality parameters of sweet potato tuber i.e. total, reducing and non-reducing sugar, crude fibre and crude protein were also estimated. In general, higher and comparable reducing sugar and total sugar content was observed in treatments which received higher doses of N : P2O5 : K2O and in tubers from organic nutrient management. Content of non-reducing sugar, crude fibre and crude protein did not vary significantly and the average values were 6.7, 2.6 and 14.3 % respectively. The soil chemical parameters in post-harvest soil showed a decline in pH and EC except in organic management where an increase in soil pH could be observed. The organic carbon was influenced by nutrient management however, it was in medium range in all the treatments. The average N, P and K uptake by sweet potato was 281, 10 and 156 kg/ha respectively, and the corresponding values for calcium, magnesium and sulphur were 20, 13 and 17 kg/ha respectively. Application of recommended dose of N : P2O5 : K2O along with 40 kg/ha magnesium sulphate resulted in the highest gross return (Rs. 5,38,500), net return (Rs. 4,05,619) as well as B:C ratio (4.1). Organic nutrient management system was the next best treatment with a net return of Rs. 2,88,050 and B:C ratio of 2.5. Hence N : P2O5 : K2O @ 75:50:75 along with 40 kg/ha of magnesium sulphate can be recommended in soils deficient in Mg for enhancing productivity of sweet potato. The results also indicate that organic nutrient management also will be economically viable in sweet potato production if premium price can be assured for the produce.ThesisItem Open Access Chemical Priming for improving salinity tolerance in rice(Department of Agronomy, College of Agriculture, Vellanikkara, 2020) Liz J, Kappen; KAU; Deepa, ThomasMeasures to improve abiotic stress tolerance in plants is gaining importance due to raised concerns on climate change and food security issues all over the world. Though different methodologies for combating abiotic stress like conventional breeding and molecular breeding have been in existence, they are often limited by time and biosafety concerns respectively. Chemical priming is a cost-effective approach in managing abiotic stress. It is reported that use of chemicals, both synthetic and natural, prior to stress events can enhance tolerance to abiotic stresses such as salinity and drought. Application of chemical agents externally can impart a minor stress which will help to generate stress signals that can lead to certain biological changes resulting in increased stress tolerance in later stages of the crop. Rice is a crop badly affected by salinity. Use of chemicals such as beta amino butyric acid (BABA), sodium nitroprusside and calcium chloride as seed primers to improve salinity tolerance may turn promising. With this objective a study was formulated with three experiments. The experiments were screening rice varieties for salinity tolerance, effect of seed priming on germination of rice varieties under salt stress condition and field trial to assess the effect of priming in rice fields with saline water intrusion. The First experiment was a lab study to screen three rice varieties namely Jyothi, Uma and Vytilla-10 at five salinity levels i.e., non-saline, 3 dS/m, 6 dS/m, 9 dS/m and 12 dS/m. Based on the results it was concluded that at 16 DAS with salinity level of 6 dS/m variety Vytilla-10 was highly tolerant (score 1). Variety Jyothi was found susceptible at 6 dS/m (score 7) whereas variety Uma was moderately tolerant (with score 5). At 21 DAS, varieties Uma and Vytilla-10 were found to be susceptible at salinity levels of 6 and 9 dS/m respectively with a score of 7. Objective of second experiment was to assess whether chemical priming could improve salinity threshold of the three varieties. The design used was two factorial CRD with three replications. The treatments were four priming chemicals and two salinity levels. Based on the results of the first experiment, threshold salinity level for Jyothi, Uma and Vtyilla-10 were estimated. Jyothi and Uma were susceptible at 6 dS/m, while Vytilla-10 was susceptible at 9 dS/m. Therefore, in second experiment variety Jyothi, salinity levels of 6 dS/m and 9 dS/m, for variety Uma salinity levels of 6 dS/m and 9 dS/m and for Vytilla-10 salinity levels 9 dS/m and 12 dS/m were taken. Each variety was primed using three chemicals, namely beta amino butyric acid (BABA 1 Mm/L), sodium nitroprusside (SNP,100 μM) and calcium chloride (CaCl2, 2%), water priming was included as control. The efficacy of each priming chemical was analyzed based on germination percentage, growth parameters and visual salt injury symptoms. Priming seeds with calcium chloride was found to influence both the growth parameters and salinity tolerance of seedlings. Based on the results of second experiment, a field trial was undertaken to assess the efficacy of priming chemicals as seed primers and as foliar spray. An experiment was laid out at Rice Research Station, Vytilla in factorial RBD with three replications. The treatments were three priming chemicals namely beta amino butyric acid (BABA), sodium nitroprusside (SNP) and calcium chloride (CaCl2), with water priming as control and three foliar sprays at weekly intervals, fortnightly intervals and weekly water spray. Rice variety Vytilla-10 was used for the study. The seedlings were transplanted to main field and foliar spraying of priming chemicals was done at weekly intervals at 30, 37 and 45 DAS, fortnightly intervals at 30, 45 and 60 DAS as well as weekly water spray. Calcium chloride seed priming was found effective in increasing plant height at 60 DAT, leaf area index, number of panicles, percentage of filled grains, thousand grain weight, yield, proline content in leaf and chlorophyll content (at 60 DAT). Most of the growth and yield parameters were influenced by weekly spray of calcium chloride. More tillers/m2 was observed in seedlings primed using SNP and weekly foliar spraying of SNP was effective in increasing tillering. Total chlorophyll content was found to increase with SNP seed priming and foliar spraying of SNP at fortnightly intervals was found most effective at 60 DAT to increase chlorophyll content. Grain filling was found to increase with BABA seed priming and weekly foliar spray of the same chemical was highly effective. Priming rice seeds with 2 % calcium chloride and foliar spraying of calcium chloride at 2 % on a weekly basis was found to be a reliable method to combat salinity stress and for improving growth, yield and yield attributes of rice.ThesisItem Open Access Perfomance of high yielding varieties of finger millet [Eleusine coracana (L.)] (Gaertn)(Department of Agronomy, College of Agriculture, Vellanikkara, 2020) Kishore, Neeruganti; KAU; Prameela, PAn experiment entitled “Performance of high yielding varieties of finger millet (Eleusine coracana (L.) Gaertn)” was undertaken during the period from July 2018 to January2019 at the Agronomy Farm, College of Agriculture, Vellanikkara, Thrissur.The objective of the experiment was to evaluate the performance of some prominent high yielding varieties of ragi suitable for Kharif and Rabi seasons in central Kerala. Randomized block design was adopted with nine varieties and three replications in both seasons. The plot size was 5 m x 4 m and the seeds were line sown at a spacing of 25 cm x 15 cm. The high yielding varieties included were VR 708 (Champavathi), Vakula, Hima, Maruthi and PR 202 (Godavari) (released from Andhra Pradesh), GPU 48, GPU 28 and KMR 201 (released from Karnataka) and Co15 (released from Tamil Nadu). All the management practices were done as per Package of Practices Recommendations of KAU. Observations on growth parameters were taken at 30 DAS, flowering and at harvest. Quality parameters of grain (crude protein, crude fibre, Ca and Fe), yield and yield attributes were also recorded. Varietal differences were significant with respect to plant height. In Kharif, when plant height was recorded at harvesting, GPU 28 (109.71 cm) and PR 202 (111.07 cm) were superior to all other varieties with statistically comparable values. The shorter varieties were GPU 48 (77.75 cm) and VR 708 (78.39 cm). At this stage in Rabi, CO15 had the tallest plants (100.41 cm). However, PR 202 also had statistically comparable plant height (98.65 cm). VR 708, Maruthi and GPU 48 were statistically on par and were inferior to other varieties with plant height in the range 72.17cm to 73.99cm. The varieties differed significantly with respect to total number of tillers in both the seasons. In general, Rabi crop had a greater number of basal tillers than the Kharif crop. The average number of basal tillers was 5.80 in Kharif and 6.80 in Rabi. In Kharif, variety VR 708 (9.27) was statistically superior with respect to basal tillers produced than other varieties. Variety Vakula produced only 3.6 tillers per plant. In Rabi, the greater number of tillers were produced by VR 708 (10.27) and CO15 (9.93). Total number of tillers showed an increase in most of the varieties, and in Hima and Vakula, a sharp increase in tiller number during Rabi was registered compared to Kharif. Seasonal differences were not pronounced in many varieties with respect to days to flowering but variation to the extent of up to 11 days was noticed in variety GPU 28. On an average, the days to 50 per cent flowering was 69 in Kharif and 72 in Rabi season. In Kharif season, PR 202 took the longest period for 50 percent flowering (79 days). The calcium content in ragi grain showed wide variability among varieties ranging from 326mg/100g to 564 mg/100g over the seasons and Fe content was in a narrow range of 6.25 – 8.91 mg/100g. There was no significant difference in fibre content of various varieties. More productive tillers were produced by CO15 and the minimum number of productive tillers were produced by Maruthi. Wide variations in finger length was observed among varieties and the values ranged from 5.30cm to 11.87 cm in Kharif and 6.23 to 11.97 cm in Rabi season. Vakula had the highest value in both seasons and was significantly superior to all others. The test weight ranged from 1.53 to 3.53 g in Kharif and from 1.51 to 3.25 g in Rabi among the varieties. Variety PR 202 had the highest 1000 grain weight of 3.53g. The average straw yield was 3592 kg/ha in Kharif whereas a higher value of 4010 kg/ha was realized in Rabi. The highest straw yield was for KMR 201(5100 kg/ha & 5141 kg/ha in Kharif and Rabi)) which was on par with GPU 48 (4578 kg/ha) in Kharif. The straw yields were low in Maruthi (3059.7 kg/ha), Vakula (3388.8 kg/ha) and VR 708 (3550 kg/ha) in both seasons. Among the nine varieties tried, six varieties - GPU 48, GPU 28, Hima, CO15 , PR 202 (Godavari) and KMR 201 performed better in Kharif as well as in Rabi season. The variety KMR 201 was found to be superior in terms of yield in both the seasons (3008.3 and 2737 kg/ha, respectively), whereas the white seeded variety Hima was found to be ideal for Rabi season due to its superior yield of 3092 kg/ha . Variety CO15 showed more adaptability to Kharif with grain yield of 2355 kg/ha and the performance was poor in Rabi (1833.33 kg/ha). Three varieties VR 708, Vakula and Maruthi are not ideal varieties for Kerala especially for Kharif seasonThesisItem Open Access Weed management for upland rice(Department of Agronomy, College of Horticulture, Vellanikkara, 2020) Basila, Y; KAU; Anitha, SRice is one of the principal food crops in Asia and can be grown in wetland and upland conditions. Upland rice is grown in rainfed, naturally well drained soils with bunded or unbunded fields without surface water accumulation. Moisture stress, weed infestation, poor soil fertility and incidence of pests and diseases are major problems in upland rice cultivation. Among these, weeds are considered to be most serious. Hence an effective and timely control of weed is essential to achieve higher productivity in upland rice. Field experiment was conducted at Agronomy Farm, College of Horticulture, Vellanikkara from June 2019 to September 2019 to develop cost effective weed management strategy for upland rice. The experiment was laid out in RBD with eight treatments and three replications. Treatments were T₁: Brown manuring (Cowpea) by application of 2,4-D on 25 DAS, T₂: In situ green manuring (Cowpea), on 25 DAS, T₃: Oxyfluorfen on the day of sowing fb HW at 30 DAS, T₄: Oxyfluorfen on the day of sowing fb bispyribac sodium on 20 DAS, T₅: Pyrazosulfuron on 6 DAS fb HW at 30 DAS, T₆: Pyrazosulfuron ethyl on 6 DAS fb bispyribac sodium on 20 DAS, T₇: Hand weeded control and T₈: Unweeded control. Dominant grass weed species observed were Echinochloa colona, Digitaria sanguinalis, Eleusine indica, Panicum maximum, Setaria spp, and Brachiaria spp. Dominant broad-leaf weed species were Alternanthera bettzickiana, Mitracarpus hirtus, Euphorbia hirta, Euphorbia geniculata, Ludwigia perennis, Scoparia dulcis, Ageratum conyzoides, Phyllanthus amara, Cleome burmannii, Commelina benghalensis, Lindernia crustacea, Catharanthus pusillus, Trianthema portulacastrum, Mollugo disticha and Hemidesmus indicus. Cyperus iria was the only sedge observed in the experimental field. Lowest weed dry matter production was recorded in hand-weeded control at 20 and 45 DAS. Application of oxyfluorfen fb HW at 30 DAS was as effective as hand weeded control and resulted in lesser weed count, weed dry matter, weed index and high weed control efficiency. Application of oxyfluorfen fb HW at 30 DAS resulted in maximum WCE of 92.60 % at 20 DAS and 98.58 % at 45 DAS. Lowest weed index was resulted from oxyfluorfen fb HW at 30 DAS (5.02 %) and was on par with pyrazosulfuron-ethyl on 6 DAS fb HW at 30 DAS (10.35 %). In situ green manuring and brown manuring resulted in significant reduction in weed dry matter production and high WCE at early stages of crop growth as compared to unweeded control, but it was not as effective as herbicide application. Application of oxyfluorfen fb HW at 30 DAS resulted in highest number of tillers per hill, leaf area index and number of hills/m². Hand-weeded control resulted in significantly higher grain yield (2888 kg/ha) and was on par with application of oxyfluorfen fb HW at 30 DAS (2743 kg/ha) and pyrazosulfuron-ethyl fb HW at 30 DAS (2589 kg/ha). Weed competition resulted in 78.05 % yield reduction in upland rice. Oxyfluorfen fb HW at 30 DAS resulted in highest straw yield (5898 kg/ha), which was on par with pyrazosulfuron-ethyl fb HW at 30 DAS (5886 kg/ha) and hand-weeded control (5415 kg/ha). Unweeded control resulted in significantly lower grain yield (634 kg/ha) and straw yield (943 kg/ha). Application of oxyfluorfen fb HW at 30 DAS resulted in higher N uptake by rice at all stages of observation and higher P uptake at harvest. At 30 DAS, application of pyrazosulfuron-ethyl fb bispyribac sodium resulted in higher P and K uptake by rice. At 60 DAS, the treatment brown manuring resulted in higher P uptake and application of oxyfluorfen fb bispyribac sodium resulted in higher K uptake by rice. At harvest, application of pyrazosulfuron-ethyl fb HW at 30 DAS resulted in higher K uptake by rice. Less N, P and K removal by weeds was observed in treatments oxyfluorfen fb HW at 30 DAS and hand-weeded control. Brown manuring resulted in higher organic carbon and soil microbial biomass carbon. Higher soil N and P availability was recorded in plots sprayed with oxyfluorfen fb bispyribac sodium and higher soil K availability was in pyrazosulfuron-ethyl on 6 DAS fb HW at 30 DAS. Application of oxyfluorfen 23.5 EC @ 0.15 kg/ha on the day of sowing fb HW at 30 DAS resulted in higher gross return, net return and B: C ratio, which was on par with pyrazosulfuron-ethyl 10 WP @ 0.03 kg/ha on 6 DAS fb hand weeding at 30 DAS. Hence, either of these pre-emergence herbicides followed by one hand weeding at 30 DAS can be recommended for a cost effective weed management in upland rice.ThesisItem Open Access Micronutrient management of sweet corn (Zea mays var. saccharata) hybrids for yield and quality(Department of Agronomy, College of Agriculture, Padannakkad, 2020) Deepa Mary, Varghese.; KAU; Vandana, VenugopalAn investigation entitled “Micronutrient management of sweet corn (Zea mays var. saccharata) hybrids for yield and quality” was undertaken with the objectives to evaluate the performance of sweet corn hybrids for yield and quality and to study the role of zinc and boron in increasing the productivity, quality and profitability of the crop. The study was carried out at College of Agriculture, Padannakkad and Regional Agricultural Research Station, Pilicode during 2019-2020. The experiment was laid out in factorial randomized block design with 12 treatments replicated thrice. The treatment combinations included three hybrids viz., H1- Sugar 75, H2- KSCH 333, H3- Misthi and four levels of micronutrient application viz., M1- RDN of Maize as per KAU POP (control), M2- RDN of Maize as per KAU POP + Spray of Boron as Solubor @ 0.15 per cent once at tasseling and silking, M3- RDN of Maize as per KAU POP + Spray of Zinc as ZnSO4 @ 1.0 per cent at 20 and 40 days after sowing and M4- RDN of Maize as per KAU POP + Spray of Boron as Solubor @ 0.15 per cent once at tasseling and silking + Spray of Zinc as ZnSO4 @ 1.0 per cent at 20 and 40 days after sowing. Perusal of the results on growth attributes revealed that sweet corn hybrids did not significantly influence plant height, number of leaves, leaf area, days to 50 per cent tasseling and silking, days to maturity and number of harvests. However, significant effects of hybrids were recorded in dry matter production. Highest dry matter accumulation was noticed in Sugar 75 (12027 kg ha-1) and was statistically on par with Misthi (9962 kg ha-1). Recommended dose of nutrients alone had resulted in highest plant height at 15 DAS and was on par with combined foliar application of zinc and boron. Leaf area was recorded maximum at 15 and 45 DAS in control plot and at 45 DAS, the treatment was on par with foliar application of zinc. Number of days taken for 50 per cent tasseling, silking and maturity was least in the control plot. Number of harvests did not differ significantly with micronutrient application. However, growth attributes did not show any significant variation between hybrids and their interaction with zinc and boron. Hybrids did not differ in any of the yield attributes recorded. However, total cob yield and green stover yield varied significantly with hybrids. Among the different hybrids tested, Sugar 75 was superior recording a cob yield of 11102 kg ha-1. Green stover yield was the highest in Sugar 75 (20667 kg ha-1) and was on par with Misthi (19111 kg ha-1). Among the yield attributes, the highest cob length was noticed in the control plot and was on par with foliar application of zinc and boron. Maximum cob girth was recorded in the control plot and was statistically on par with foliar application of zinc. Cob weight without husk was maximum when treated with recommended dose of fertilizers alone and was on par with foliar application of boron. Foliar nutrition with either zinc, boron or both had no influence on number of cobs per plant, number of kernel rows per cob, number of kernels per cob, hundred fresh kernel weight, cob weight with husk, total cob and stover yield. Visual symptoms of boron deficiency were observed in cobs irrespective of the treatments. The hybrids and their interaction with foliar application of micronutrients did not show significant influence on yield attributes. However, maximum cob yield (11640 kg ha-1) was recorded when recommended dose of nutrients alone were given and among interaction effects, the highest cob yield (13813 kg ha-1) was recorded when Sugar-75 was provided with recommended dose of nutrients alone and was on par with KSCH 333 and recommended dose of nutrients alone (13247 kg ha-1). Organic carbon and available boron content in the soil was not significantly influenced by hybrids, micronutrient application and their interaction. However, after harvest, there was an increase in the organic carbon content in the soil. Available boron content in the soil was in deficient range before and after the experiment. Chlorophyll content did not vary significantly with hybrids and micronutrient application. Highest chlorophyll content (2.44 mg g-1) was recorded when KSCH 333 was treated with recommended dose of fertilizers alone and was on par with all the interaction effects except when KSCH 333 was treated with foliar application of zinc and boron. Ascorbic acid content and moisture content was not significant among treatments. Among the hybrids, mean per cent damage by fall army worm was recorded the lowest in Misthi. Micronutrient application and their interaction with hybrids did not significantly influence the pest incidence. Highest net profit of ₹ 225710 ha-1 and BCR of 2.03 was realized with Sugar 75. Therefore, it can be concluded from the study that growing sweet corn hybrid Sugar 75 is beneficial for getting higher yield per unit area and maximum economic returns. Visual symptoms of boron deficiency were evident, reflected as unfilled kernel rows within the cobs of sweet corn. The study also reveals that boron is a critical nutrient that influences the yield and yield attributes in sweet corn. Foliar application of boron @ 0.15 per cent once at tasseling and silking did not meet the requirements of the crop when grown in boron deficient soil. Hence, foliar application of a nutrient alone cannot alleviate the nutrient deficiency in the crop when grown under limited soil nutrient supply.ThesisItem Open Access Biology and management of goose weed (Sphenoclea zeylanica Gaertner) in wetland rice(Department of Agronomy, College of Agriculture, Vellayani, 2020) Mallu Sai Sarath Kumar, Reddy.; KAU; Ameena, MAn investigation entitled ‘Biology and management of goose weed (Sphenoclea zeylanica Gaertner) in wetland rice’ was conducted at College of Agriculture, Vellayani during 2018-2020. The major objectives were to study the biology of the weed, its allelopathic effect on crop and also to develop an effective and economic management strategy using herbicides in wet seeded rice. The field experiment was undertaken at IFSRS, Karamana during kharif 2019. Weed biology was studied by observing randomly selected sample plants in weedy check plots starting from the emergence of the weed. The field experiment was laid out in randomized block design with eight treatments and three replications. The weed control treatments included T1: bensulfuron methyl + pretilachlor @ 60+600 g ha-1 at 5 days after sowing(DAS), T2: pyrazosulfuron ethyl @ 25g ha-1 at 5 DAS, T3: bispyribac sodium @ 25 g ha-1 at 15-20 DAS, T4 :penoxsulam + cyhalofop butyl 6% OD at 150 g ha-1 at 20 DAS, T5: metsulfuron methyl + chlorimuron ethyl @ 4g ha-1 at 20 DAS, T6: ethoxysulfuron @ 15 g ha-1 at 20 DAS, T7 : hand weeding at 20 and 40 DAS, T8 : weedy check ( unweeded control) and the treatments T1 to T6 were followed by hand weeding at 35-40 DAS. The lab experiment on allelopathic effect of goose weed on germination and growth of rice seedlings was evaluated with treatments T1: Fresh leaves aqueous extract 10%, T2: Dry leaves aqueous extract 10%, T3: Fresh stem aqueous extract 10%, T4: Dry stem aqueous extract 10%, T5: Fresh inflorescence aqueous extract 10%, T6: Dry inflorescence aqueous extract 10%, T7: Fresh whole plant aqueous extract before flowering 10%, T8: Fresh whole plant aqueous extract after flowering 10%, T9: Distilled water (control). The data on weed biology identified goose weed as an annual. The weed seeds took 3-7 days for germination, 15 days for flowering and 36 days for first spike maturity with an average duration of 69 days in wet seeded rice fields. The weed was observed to propagate by seeds with enormous seed production potential. The average dry matter produced per plant and total dry matter production were to the tune of 26.24 g per plant and 3.75 t ha-1 respectively in the weedy check. The weed was analysed to contain 1.306, 0.087 and 1.695 per cent N, P and K respectively. In the field experiment, Sphenoclea zeylanica was the dominant weed flora during all the growth stages of the crop. Initially, a lower weed density was recorded in T1, but taken over by T4 at 30, 45 and 60 DAS. The weed dry weight was the lowest in T1 at 15 and 30 DAS (0.08 and 6.41 g m-2), whereas at 45 and 60 DAS, T4 recorded the lowest values (1.35 and 4.61 g m-2). T1 registered lesser relative weed density of S. zeylanica up to one month and later by T4. Unweeded plot showed dominance of the weed over other flora with a relative density of 70.33 per cent. Though weed control efficiency was higher in T1 upto 30 DAS (99.28 and 96.22 per cent), T4 recorded higher values during critical stages of crop growth at 45 and 60 DAS (99.54 and 98.85 per cent). T4, T1 and T5 recorded minimum NPK removal and to be precise only one tenth of N removal registered in weedy check in comparison to others due to lower weed dry matter accumulation Among the weed management practices tested, T1 recorded higher plant height at 30, 60 DAS and at harvest. Both T1 and T4 recorded higher yield and yield attributes like number of panicles m-2(320 and 308.3), number of grains panicle-1 (173 and 177), grain yield (5461 and 5355 kg ha-1) and straw yield (7710 and 7646 kg ha-1). Bensulfuron methyl + pretilachlor @ 60+600 g ha-1 at 5 DAS followed by hand weeding at 35-40 DAS turned out to be the most economic weed management practice with a higher B: C ratio of 1.83. This was followed by penoxsulam + cyhalofop butyl 6% OD at 150 g ha-1 at 20 DAS followed by hand weeding at 35-40 DAS with a B: C ratio of 1.77. Higher nutrient uptake by the crop was noticed in bensulfuron methyl + pretilachlor (T1), T4 and T5 due to higher dry matter production. The extent of yield reduction due to presence of weeds in wet seeded rice was estimated to be 57 per cent. The study on allelopathic influence of goose weed revealed strong inhibitory influence for its dry leaves and dry inflorescence on germination percentage (92.67 and 80%) and dry weight (96.98 and 96.12%) of rice seedlings. Shoot length, root length, fresh weight, dry weight and vigour index were also recorded the lowest in T2 and T6. From the results of the study, it could be concluded that Sphenoclea zeylanica could become a serious weed in wetland rice fields being a prolific seed producer with high dry matter production. Application of bensulfuron methyl + pretilachlor @ 60+600 g ha-1at 5 DAS followed by hand weeding at 35-40 DAS was found to be the most effective and economic management strategy. The inference of allelopathic studies indicated that dry leaves and inflorescence of goose weed have strong inhibitory influence affecting germination and growth of rice.ThesisItem Open Access Performance evaluation of rice varieties and their response to zinc nutrition in uplands(Department of Agronomy, College of Agriculture, Vellayani, 2020) Ramya Chandra, C.; KAU; Prathapan, KA field trial entitled “Performance evaluation of rice varieties and their response to zinc nutrition in uplands” was conducted during Kharif 2019 (May – August 2019) at Coconut Research Station, Balaramapuram. The objective of the study was to find out a suitable rice variety for uplands in red loam tracts of Kerala and to standardize the dose and method of zinc application. The experiment was conducted in Factorial Randomized Block Design with varieties as first factor and zinc sulphate application as second factor in three replications. Three varieties were used for the experiment were Anna 4 (V1), APO 1 (V2), and Prathyasa (V3) and the zinc sulphate application comprised of seed priming with ZnSO4 @ 2g kg -1 seed (S1), foliar application with ZnSO4 @ 0.5 per cent at active tillering stage and panicle initiation stage (S2), combination of S1 and S2 (S3), soil application of ZnSO4 @ 20 Kg ha-1 (S4), and control (without ZnSO4 application) (S5). Crop was manured with FYM @ 5 t ha-1and N:P:K @ 90:30:45 kg ha-1 (Suman, 2018). Varieties had significant effect on plant height, tillers per m2, root shoot ratio and dry matter production (DMP). Among the varieties V2 (APO 1) shown significantly higher plant height and root shoot ratio. Variety V3 (Prathyasa) shown significantly higher tiller m-2 and DMP. Zinc sulphate application had significant effect on growth attributes viz., tillers m-2, Leaf area index (LAI), root shoot ratio and DMP. Combination of seed priming and foliar application (S3) recorded significantly higher tillers per m-2, Leaf area index, root shoot ratio and DMP. Interaction of varieties and zinc sulphate application was significant in tillers m-2, LAI, root shoot ratio and DMP. The treatment V2S4 recorded the highest DMP (11732.37 kg ha-1). Varieties, zinc sulphate application and their interaction shown significant effect on crop growth rate (CGR), relative water content, soluble protein, proline content and stomatal conductance but only zinc sulphate application had significant effect on chlorophyll content. Varieties, zinc sulphate application and their interaction had significant effect on nutrient uptake. Among the varieties phosphorus and Zn uptake was higher in V3 (prathyasa) and potassium uptake was higher in V2 (APO 1). Among the method of zinc sulphate application higher uptake was noted in soil application (S4). Varieties had significant effect on available potassium and zinc. Zinc sulphate application had significant effect on available nutrients after the experiment. Varieties had significant effect on yield attributes viz., panicle length, panicle weight, panicles m-2, filled grains per panicle, sterility percentage and thousand grain weight. However, zinc sulphate application had significant effect only on panicle weight, filled grains per panicle, sterility percentage and thousand grain weight. Among the varieties, the highest number of panicles m-2 and the highest number of filled grains per panicle were recorded in the V3 (Prathyasa). The highest panicle weight was recorded in V2 (APO 1) and the highest panicle length, the highest thousand seed weight and the lowest sterility percentage were recorded in V1 (Anna 4). Among the method of zinc sulphate application, foliar application (S2) recorded the highest panicle weight, combination of seed priming and foliar application (S3) recorded higher number of panicles m-2, filled grains per panicle, the lowest sterility percentage and grains with higher thousand grain weight. Grain yield was also significantly influenced by varieties and zinc sulphate application. Among the varieties, V3 (Prathyasa) recorded significantly higher grain yield among the varieties (3,524.03 kg ha-1). Compared to control, all method of zinc application recorded higher grain yield. Combined application of seed priming and foliar application (S3) recorded the highest grain yield (3,877.71 kg ha-1) among the different methods of zinc sulphate application. The interaction between varieties and zinc sulphate application also had significant effect. Among the varieties, APO 1 (V2) recorded the highest straw yield and it was significantly superior to other treatments. Soil application of ZnSO4 @ 20 kg ha-1 recorded the highest straw yield. Among the varieties, prathyasa (V3) recorded the highest net returns (38,921 ha-1) and B C ratio (1.58). Among zinc sulphate application, S3 (seed priming with zinc sulphate 2 g kg-1 seed + foliar application of zinc sulphate 0.5 per cent at active tillering and panicle initiation stage) recorded highest net returns (47,897 ha-1) and B C ratio (1.71). Considering the yield, economics and B:C ratio, variety prathyasa (V3) performed well with application of NPK @ 90:30:45 kg ha-1,seed priming with zinc sulphate 2 g kg-1 seed + foliar application of zinc sulphate 0.5 per cent at active tillering and panicle initiation stage (S3) for uplands in red loam tracts of Kerala.ThesisItem Open Access Standardisation of growth media and organic nutrient schedule for container cultivation of spinach beet (Beta vulgaris var. bengalensis)(Department of Agronomy, College of Agriculture, Vellayani, 2020) Aisha, Majeed; KAU; Ameena, MAn investigation entitled ‘Standardization of growth media and organic nutrient schedule for container cultivation of spinach beet (Beta vulgaris var.benghalensis)’ was conducted at College of Agriculture Vellayani, Thiruvananthapuram during 2019-20. The objective of the study was to identify an ideal growth medium and to standardise an organic nutrient schedule for container cultivation of spinach beet. The study was conducted as two separate experiments with a field study and a concurrent lab incubation study on nutrient availability in different growth media. The first experiment was conducted during the rabi season of 2019 at College of Agriculture, Vellayani. The treatments consisted of five growth media {M1: soil : sand : FYM (1: 1 : 1), M2 - soil: rockdust: FYM (1:1:1), M3 - soil: compressed coirpith: FYM (1:1:1), M4- soil: rockdust: compressed coirpith: FYM (1:0.5:0.5:1), M5 - soil: suchitha : FYM (1:1:1) and three nutrient levels (N1 - 100% of 80:40:80 kg NPK ha-1 , N2 - N1 + 50% N topdressed in 3splits , N3 - N1+ 100% N topdressed in 3splits). The recommended dose of NPK@ 80:40:80 kg ha-1 was given as basal through the nutrient source poultry manure. In N2 and N3, nitrogen was topdressed as fermented groundnut cake at 20, 40 and 60 DAT. The experiment was laid out in completely randomized design with three replications. The crop was raised in UV stabilized woven plastic sacks of thickness 1400 denier capable of holding 15 kg potting mixture with 15 treatment combinations. Results of the study indicated that among the growth media, M5 registered superior values for growth parameters, viz., leaf yield per plant (118.08 g), leaf area index (2.07 at 75 DAS), dry matter production (33.05 g plant -1) and leaf yield per harvest (32.67 g per plant at second harvest) and was on par with M2. The major yield determining parameter viz., number of leaves harvested per plant was superior in M2 and was on par with M5 and M1. Root parameters including root weight and root shoot ratio were also found higher in M5. The quality parameters including vitamin A and C were found higher in M2 and the iron content was found higher in M1. M5 recorded higher uptake of N, P and K and it was significantly superior over all other growth media. The different nutrient levels did not exert any significant influence on leaf yield per harvest, leaf yield per plant and dry matter production. Between the nutrient levels, N1 recorded the highest number of leaves harvested per plant (23.29), Leaf Area Index (1.63 at 75 DAS) root weight (12.66 g) and iron content (2.5). However, the vitamin C and A content were significantly higher in N3. N2 recorded higher N uptake and nutrient levels didn’t exert significant influence on P and K uptake. Among the interactions, m5n1 was found significantly superior with respect to leaf yield per plant, LAI and dry matter production. Maximum leaf yield per harvest was also recorded in m5n1which was on par with m2n1. The root weight and root shoot ratio were found higher in m5n2. The treatment combination m5n3 registered the highest vitamin C and vitamin A content was higher in m4n3, m3n3 and m3n1.The treatment combination m1n1 recorded higher iron content. The interactions m4n2 recorded higher uptake of N which was on par with m5n1. The interaction m5n1 recorded higher K uptake and it was significantly superior over all other interactions. Even though m5n1 recorded higher leaf yield, the net income and BC ratio were lower due to higher unit cost of suchitha. The individual effects of M2, N1 and their combination m2n1 recorded the highest net income (4.85 ₹ bag-1) and benefit cost ratio (1.67). The concurrent lab incubation study on nutrient availability in different growth media was conducted in Completely Randomised Design with 15 treatments replicated thrice. The five-growth media combinations were uniformly supplied with the recommended dose of NPK (80:40:80 kg ha -1) as poultry manure and groundnut cake at respective intervals. The growth media samples analysed at monthly intervals indicated an increased release of nutrients in available form over the period. Prior to the experiment all the growth media recorded a pH range of 6.5 to 7 which showed an increasing trend. The growth combination with coirpith (M3) recorded slightly higher EC values (1.52) compared to other combinations. Initial content of organic carbon, available N and P in the media were higher in M5 and it gradually increased during the period of incubation with M2 recording a higher organic carbon content at second and third month. The available nitrogen status showed an increasing trend among the growth media combinations during incubation with M2 and M3 recording higher values. Though M5 recorded a higher initial available P status, M4 with rockdust and coirpith as media components recorded a significantly higher available P status after second and third month of incubation. Though higher initial available K was observed in M3, M1 recorded higher available K after incubation. Among the nutrient levels, N3 recorded higher available N, P and K during the period of incubation. Among the interactions, m2n2, m4n3 and m3n1 recorded higher available N, P and K status during incubation. From the results of the experiments conducted, the best growth medium and nutrient schedule for container grown spinach beet can be summarised as • Growth media: soil: suchitha: FYM in 1: 1: 1 ratio on volume basis with respect to yield and soil: rockdust: FYM in 1: 1: 1 ratio on volume basis with respect to quality and economics • Organic nutrient schedule: 100% recommended dose of 80:40:80 kg NPK ha-1 with entire dose as basal applicationThesisItem Open Access Intercropping vegetables in baby corn (Zea mays L.)(Department of Agronomy, College of Agriculture, Vellayani, 2020) Anna, Emmanuel; KAU; Rajasree, GThe study entitled “Intercropping vegetables in baby corn (Zea mays L.)’’ was conducted at College of Agriculture, Vellayani, Thiruvananthapuram during 2018-20 to investigate the feasibility of intercropping vegetables (cowpea and amaranthus) in baby corn and to find the effect of crop geometry on growth, yield, productivity and economics of intercropping systems. The field experiment was conducted during March to May 2019 and was laid out in Randomized Block Design with 3 replications. Baby corn (var. G 5414) was raised as main crop and cowpea (var. Bhagyalakshmi) and amaranthus (var. Arun) were raised as intercrops in various cropping geometries. The treatments consisted of different planting geometries of baby corn with cowpea and amaranthus as intercrops along with sole crop treatments, viz., T1- baby corn + cowpea (skip row), T2- baby corn + amaranthus (skip row), T3- baby corn + cowpea (paired row), T4- baby corn + amaranthus (paired row), T5- baby corn + cowpea (2:1 ratio), T6- baby corn + amaranthus (2:1 ratio), T7- sole crop of baby corn, T8- sole crop of cowpea and T9- sole crop of amaranthus. The results indicated that intercropping cowpea or amaranthus in baby corn had significant influence on the growth and yield of both main crop and intercrops. The cob yield with husk (11.39 t ha-1), marketable cob yield (3.53 t ha-1) and cob weight with husk (49.50 g) of baby corn were found to be significantly higher in T3 compared to other treatments including sole crop of baby corn. The number of cobs per plant recorded was the highest in T1 which did not differ from T2. Cob-to corn ratio of baby corn was significantly lower in treatments T4 and T3. The highest dry matter production (24453 kg ha-1) and green stover yield (39.33 t ha-1) of baby corn were recorded in T3 which was on par with T7.Growth and yield of intercrops were significantly reduced under intercropping. Sole crop of cowpea (T8) produced higher number of primary branches, LAI, total dry matter production, root volume, root depth, number of pods per plant, pod yield per plant and pod yield per ha compared to intercropping systems. Sole crop of amaranthus (T9) also produced significantly higher LAI, total dry matter production, yield per plant and yield per ha when compared to intercropping systems. The light interception by the crop canopy of baby corn was found to be the highest in T3. Higher uptake of N, P and K were recorded in intercropping treatment T3 (growing baby corn and cowpea in paired row). The sole cropping of intercrops however resulted in the highest N, P and K uptake compared to the intercropping. Analysis of competitive indices of intercropping system revealed that the land equivalent ratio (LER), baby corn equivalent yield (BEY) and monetary advantage index (MAI) were the highest in T3. The positive aggressivity value (Abv) and higher relative crowding coefficient of baby corn (Kb) indicated the competitive nature and dominance of baby corn over intercrops. The paired row planting of baby corn with cowpea (T3) produced the highest net returns (₹ 222830 ha-1) and benefit: cost ratio (3.18). The results of the study indicated that compared to amaranthus, vegetable cowpea was more suitable for intercropping with baby corn. Paired row planting of baby corn with cowpea (T3) was found to be the best intercropping system considering the planting geometry in terms of baby corn equivalent yield, monetary advantage index, net income and benefit: cost ratio.
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