Browsing by Author "Meera V Menon"

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Bio-efficacy of tank mixed herbicides and urea in wet seeded rice
(Department of Agronomy, College of Agriculture, Vellanikkara, 2021) Thumu Venkateswara Reddy; Meera V Menon
The use of herbicides has become an indispensable part of agriculture, particularly in rice cultivation, where weeds are the most harmful of the biotic constraints to production. A usual practice among rice farmers in the Kole lands of Kerala is the tank mixing of herbicides, for a broader spectrum of weed control, enhanced weed control efficiency and reduction in the cost of application. However, mixing of herbicides is done without any knowledge of the probable synergistic or antagonistic interactions on weed flora. Herbicides are also mixed with fertilizers like urea under the common belief that herbicidal efficiency is enhanced by this practice. Application of herbicides may affect various plant pathogens and microbial bioagents which occur naturally in the rice ecosystem. Information of the effect on main disease causing as well as beneficial microorganisms would help in selecting appropriate herbicides. Hence the major objectives of the research programme entitled “Bio-efficacy of tank mixed herbicides and urea in wet seeded rice” were to study the synergistic or antagonistic effect of tank mixing of commonly used herbicides, and to evaluate the efficiency of these herbicides on mixing with urea, on major weeds of rice. The effect of these herbicides on beneficial and pathogenic microorganisms were also investigated. Two field experiments were conducted at Alappad padasekharam in the Kole lands of Thrissur from October to January 2019-20 and 2020-21. The soil of experimental field was clayey in texture, high in organic carbon (1.1-1.3%), low available nitrogen (180-188 kg/ha), and medium phosphorus (20-21.5 kg/ha) and potash (152-159 kg/ha), with a soil pH of 4.5-4.7. The feasibility of mixing herbicides was evaluated in experiment I (Bio-efficacy of tank mixed herbicide combinations in wet seeded rice). There were fourteen treatments and they included tank mixtures and sequential applications of five herbicides viz., fenoxaprop-p-ethyl (0.06 kg/ha), (chlorimuron-ethyl + metsulfuron-ethyl) (0.004 kg/ha), carfentrazone ethyl (0.02 ii kg/ha), bispyribac-sodium (0.025 kg/ha), and (cyhalofop-butyl + penoxsulam) (0.15 kg/ha). These were compared with two broad spectrum herbicides, bispyribac-sodium (0.025 kg/ha) and (cyhalofop-butyl + penoxsulam) (0.15 kg/ha), as well hand weeded and unweeded controls. In experiment II (Bio-efficacy of tank mixed herbicides and urea in wet seeded rice), there were twelve treatments. Six herbicides, viz., cyhalofop butyl (0.08 kg/ha), (cyhalofop butyl + penoxsulam) (0.15 kg/ha), bispyribac-sodium (0.025 kg/ha), fenoxaprop-p-ethyl (0.06 kg/ha), carfentrazone ethyl (0.02 kg/ha) and (chlorimuron ethyl + metsulfuron methyl) (0.004 kg/ha) were applied with and without urea (1%) mixing. Hand weeded and unweeded controls were also included for comparison. Randomized Block Design with three replications was adopted for both experiments. Wet seeding of rice at the seed rate of 100 kg/ha was done. Nitrogen, phosphorus and potassium @ 90:35:45 kg/ha were supplied through urea, factomphos and muriate of potash (KAU, 2016). In experiment III (In vitro evaluation of herbicides on beneficial and pathogenic microorganisms) treatments included the effect of herbicides mentioned in experiment II which were evaluated under in vitro conditions with recommended, higher and lower doses on beneficial microbial bioagents (Trichoderma viride and Pseudomonas fluorescens) and pathogenic microorganisms (Rhizoctonia solani, Pyricularia oryzae and Xanthomonas oryzae pv. oryzae). Factorial Completely Randomized Block Design was adopted with 18 treatments and three replications each. Tank mixing of herbicides was found to be more effective than their sequential application for most of the combinations. Tank mixed combination of (cyhalofopbutyl + penoxsulam) with (chlorimuron-ethyl + metsulfuron-methyl) showed synergistic effect and had lowest weed density (32, 16 and 20 nos./m2 ), lowest weed dry matter production (14.68, 50.50 and 88.95 kg/ha), and highest weed control efficiency (91, 88, and 82%) at 15, 30 and 60 days after application respectively. The number of tillers per sq. m (411), number of panicles per sq. m (288), number of grains per panicle (103), percentage of filled grain (91.6) at harvest, nutrient uptake by rice at 60 DAS (105.06, 14.32 and 74.28 kg/ha of N, P and K respectively), grain iii yield (3.97 t/ha), net returns (Rs.71,406/ha) and benefit: cost ratio (2.25) were highest in the same treatment. The next best treatment was fenoxaprop-p-ethyl + bispyribac sodium. On tank mixing of herbicides with urea, bispyribac-sodium and urea interacted synergistically, resulting in highest weed control efficiency (82.5 and 78% at 15 and 30 days after application respectively), highest grain yield (5.03 t/ha), and profitability (Rs. 93,509/ha) over the other treatments. Mixing of (cyhalofop-butyl + penoxsulam) with urea could also be recommended for good results (grain yield of 4.94 t/ha and net returns of Rs.87,463/ha). In vitro evaluation of herbicides revealed that bispyribac-sodium and (cyhalofop-butyl + penoxsulam) had greatest inhibitory effect on pathogenic microorganisms Rhizoctonia solani and Pyricularia oryzae, but showed no effect on Xanthomonas oryzae pv. oryzae, and were less harmful to biocontrol agents Trichoderma viride and Pseudomonas fluorescens at recommended doses. Tank mix combination of (cyhalofop-butyl + penoxsulam) with (chlorimuronethyl + metsulfuron-methyl) was the best treatment with compatibility, efficient weed control, high grain yield and net returns. Tank mixing of bispyribac-sodium with urea 1% had synergistic effect resulting in highest weed control efficiency, production and profitability over the other treatments. Mixing of (cyhalofop-butyl + penoxsulam) with urea 1% could also be recommended for good results. Bispyribac-sodium and (cyhalofop-butyl + penoxsulam) were the best herbicides on in vitro evaluation in their effect on pathogenic microorganisms Rhizoctonia solani and Pyricularia oryzae, and at recommended doses were compatible with biocontrol agents Trichoderma viride and Pseudomonas flourescens.
Diversity of echinochloa spp. and their response to select herbicides
(Department of Agronomy, College of Horticulture, Vellanikkara, 2017) Aparna, K K; Meera V Menon
Effect of preceding fodder crops and fallow on productivity mechanics in first crop season rice
(Kerala Agricultural University, 1999) Meera V Menon; Achuthan Nair, M; Potty, N N
Effect of secondary nutrients on yield and quality of turmeric (Curcuma longa L.)
(Department of Agronomy, College of Horticulture, Vellanikkara, 2014) Sanghamithre, V K; Meera V Menon
Primary nutrients viz. nitrogen, phosphorus and potassium are generally regarded to be instrumental in maintaining growth, yield and quality of crops. The secondary nutrients, sulphur, calcium and magnesium, though reported to play key roles in the growth and development of crops, seldom get the recognition they deserve. There are no recommendations for these nutrients for most crops. At the same time, there are reports of increasing deficiency of sulphur, calcium and magnesium in the laterite soils of Kerala. Turmeric (Curcuma longa L.) is a vital spice crop of the Zingiberaceae family. The rhizome, which is the economic produce, contains an essential oil, curcumin and related compounds as major constituents. There is immense scope for cultivation of turmeric in Kerala due to favourable climatic and soil condition. Turmeric is a crop requiring heavy fertilization for increasing yield and quality. This research programme was taken up to study the effect of secondary nutrients on the yield and quality of turmeric. The field experiment was conducted during 2013-2014 in the farm of the Department of Agronomy, College of Horticulture, Vellanikkara. There were 10 treatments with 3 replications each. Treatments consisted of package of practices recommendations (POPR) of 40 tonnes farmyard manure along with 30:30:60 kg N, P and K/ha and its combinations with S, Ca and Mg applied one and two months after planting. Rhizomes were planted at a spacing of 25 × 25 cm and planting was done on 05 June 2013. Harvesting was done after seven months. Biometric observations were taken at monthly intervals and nutrient contents were analyzed at three and six months after planting and at harvest. Nutrient uptake was also worked out. Curcumin and oleoresin content in rhizomes were also analyzed. The soil pH and chemical parameters were determined before and after the experiment. There were significant differences among the treatments with respect to leaf area index, yield, nutrient content and nutrient uptake. In the case of leaf area index, the treatment receiving Ca as second top dressing (viz. two months after planting) recorded the highest LAI compared to other treatments. Fresh and dry yields of turmeric and benefit: cost ratio was also high in the same treatment. This treatment resulted in the highest uptake of all nutrients except S at harvest. Earlier application of sulphur, calcium and magnesium (viz. one month after planting) also led to higher yield and benefit: cost ratio, confirming the direct positive effect on yield. Absolute control recorded the lowest values for all parameters including yield and quality components. Future research should be focused on altering and testing the dose and schedule of application of S, Ca and Mg, and analysis of their interaction effect to maximize productivity, Application of micronutrients and optimizing their dose and schedule for higher yield and quality should also be attempted.
Effect of summer cropping and fallowing on the productivity of rice lands
(Kerala Agricultural University, 1999) Meera V Menon; Achuthan Nair, M; Potty, N N
Herbicidal management of chinese sprangletop (Leptochloa chinensis(L.) Nees.) in direct seeded rice)
(Department of Agronomy, College of Horticulture, Vellanikkara, 2014) Geethu Jacob; Meera V Menon
Integrated weed management in green gram (Vigna radiata (L.) Wilczek)
(Department of Agronomy, College of Agriculture, Vellanikkara, 2021) Saveri Gopakumar; Meera V Menon
Weeds are known to cause substantial yield losses in green gram, owing to the slow initial growth of the crop and severe competition by weeds. Although hand weeding has been proved effective in reducing weed infestation, unavailability of timely labour and high labour costs have created practical difficulties in adopting manual weeding on a large scale, thus increasing the dependency on chemical weed control using herbicides. However, continuous use of herbicides results in problems like environmental contamination and resistance development. The present study entitled “Integrated weed management in green gram [Vigna radiata (L.) Wilczek]” was undertaken with the objective of developing an economically viable integrated weed management strategy that provided broad spectrum weed control in green gram. The field experiment was carried out from December 2020 to March 2021 at Kotteppadam rice field under the Department of Agronomy, College of Agriculture, Vellanikkara. The experiment included eight treatments replicated thrice in a randomized block design (RBD). The treatments were: stale seed bed for 14 days followed by (fb) shallow digging (T 1 ), stale seed bed for 14 days fb shallow digging fb oxyfluorfen at 0-3 DAS (T 2 ), oxyfluorfen at 0-3 DAS fb hand weeding at 25 DAS (T 3 ), imazethapyr at 0-3 DAS fb hand weeding at 25 DAS (T 4 ), imazethapyr + imazamox at 0-3 DAS fb hand weeding at 25 DAS (T 5 ), diclosulam at 0-3 DAS fb hand weeding at 25 DAS, hand weeding at 20 DAS and 40 DAS (T 7 ) and unweeded control (T 8 ). The major broad leaved weeds observed were Melochia corchorifolia, Aeschynomene indica, Grangea maderaspatana, Phyllanthus amara, Heliotropium indicum, Mimosa invisa and Mimosa pudica, whereas Brachiaria mutica, Digitaria ciliaris, Echinochloa colona, Oryza sativa and Cynodon dactylon were the predominant grasses. Hand weeding resulted in the lowest weed density as well as weed dry matter production at all stages of observation. All the pre-emergence herbicidesintegrated with hand weeding were also equally effective, among which imazethapyr+ imazamox fb hand weeding and diclosulam fb hand weeding recorded the highest weed control efficiency of 97 per cent. Similarly, nutrient removal by weeds was the lowest in hand weeding, which was statistically similar to all the treatments where herbicide application was integrated with hand weeding. Stale seed bed provided effective control of weeds only during the early stages of crop growth. Weed density, weed dry matter production, nutrient removal by weeds and weed index were invariably the highest in unweeded control. Number of branches/plant, number of pods/plant, grain yield and haulm yield of green gram were higher in hand weeding and the treatments where herbicide application was integrated with hand weeding. Uncontrolled weed growth resulted in yield losses up to 70 per cent in green gram, which was reduced to 5.82 per cent and 8.22 per cent in imazethapyr + imazamox fb hand weeding and diclosulam fb hand weeding respectively. These treatments registered high grain and haulm yields of 549 kg and 1296 kg, and 535 kg and 1271 kg respectively. Although the application of pre-emergence herbicides resulted in a reduction in the soil microbial count at flowering as compared to the untreated plots, the population recovered by harvest stage in the plots treated with oxyfluorfen, imazethapyr and imazethapyr + imazamox. However, diclosulam was found to have a pronounced inhibitory effect on the soil microbial population at harvest as well. Available N, P and K contents in soil were found the lowest in unweeded control. Although the gross returns were the highest in hand weeding, imazethapyr + imazamox fb hand weeding and diclosulam fb hand weeding registered the highest net returns of Rs. 9,126/ha and Rs. 8,733/ha, respectively. Accordingly, B:C ratio was also the highest in imazethapyr + imazamox fb hand weeding (1.28) and diclosulam fb hand weeding (1.27). Thus, application of these two pre-emergence herbicides followed by hand weeding at 25 DAS proved highly successful in achieving season- long weed control in green gram, thereby enhancing the yields and fetching higher monetary returns.
Morphology, ecology and management of monochoria vaginalis (Burm.f.) Kunth
(Department of Agronomy , College of Horticulture, Vellanikkara, 2019) Athira G R; Meera V Menon
Non-chemical weed management in chilli (Capsicum annuum L.)
(Department of Agronomy, College of Agriculture, Vellanikkara, 2021) Fasna P; Meera V Menon
One of the major problems in any crop production system is weed infestation which causes reduction in both the yield and quality of produce. Although the use of herbicides provides effective and sustained weed control, it is not a preferred option because of environmental concerns. This is particularly true in the case of vegetables, some of which are consumed either partially cooked or raw. The research programme entitled ‘Non-chemical weed management in chilli (Capsicum annuum L.)’ was carried out with the objective of evaluation of non-chemical methods of weed management in chilli. The experiment was conducted at the Department of Agronomy, College of Agriculture, Vellanikkara from June 2020 to September 2020. The field was infested with broad leaf weeds, grasses and sedges. Randomized block design used for laying out the experiment, with seven treatments and three replications. The treatments were, T1: stale seed bed for 14 days followed by shallow digging and planting of chilli, followed by two hand weedings at 30 DAT and 60 DAT, T2: stale seed bed for 14 days followed by shallow digging and planting of chilli, followed by one hand weeding at 45 DAT, T3: black polythene mulch (30 microns), T4: straw mulch at 7.5 t/ha applied twice, at planting and one month after planting, T5: straw mulch at 7.5 t/ha applied twice, at planting and one month after planting followed by one hand weeding at 60 DAT, T6: hand weeding at 30 and 60 DAT and T7: unweeded control. Black polythene mulch (T3) recorded highest weed control efficiency and lowest weed density, weed dry matter production and weed index, whereas straw mulch when applied alone (T4) and when followed by one hand weeding (T5) were the next best treatments with high weed control efficiency and low weed index. The treatments hand weeding (T6), stale seed bed when followed by two hand weedings (T1) and one hand weeding (T2) were not effective in controlling weeds. The lowest weed control efficiency and the highest weed index values were recorded for the unweeded control (T7) at all stages of observation. Various weed management practices had significant effect on growth and yield parameters of chilli. At all stages of observation, the plant height of chilli in polythene mulching (T3) was found to be the greatest followed by straw mulching when done alone (T4) and when followed by one hand weeding (T5). Unweeded control (T7) had the lowest values. Chilli plants in polythene mulching (T3) recorded the highest number of fruits per plant (218) and fruit yield (22.44 t/ha), followed by straw mulching both when done alone (T4) (182 nos. and 18.89 t/ha respectively) and when followed by one hand weeding (T5) (177 nos. and 18.38 t/ha respectively). Hand weeding (T6) and stale seed bed when followed by two hand weedings (T1) recorded lower yields than straw mulching. Unweeded control (T7) recorded lowest values for fruit length, fruit girth, fruit weight, number of fruits per plant and fruit yield. The soil physico-chemical characteristics pH, EC, organic carbon, and available N, P and K were influenced by different weed management practices. The organic carbon content in soil was highest in polythene mulching (T3) at 60 DAT (1.45 %) and after the final harvest (1.49 %). At both stages of observation, straw mulching (T4) had highest values of available P (77 and 79 kg/ha respectively) and K (414 and 408 kg/ha respectively), whereas available N was found higher in black polythene mulch (T3) at 60 DAT (246 kg/ha) and in stale seed bed followed by one hand weeding (T2) after the final harvest (239 kg/ha). Considering the economics of cultivation, black polythene mulching (T3) recorded highest gross returns (Rs.22.44 lakhs/ha), net returns (Rs. 9.94 lakhs/ha) and B:C ratio (1.84) and was followed by straw mulching when done alone (T4) and when followed by a hand weeding (T5). Black polythene mulching was thus identified as the best non-chemical weed management technique in chilli, having highest weed control efficiency leading to enhanced growth and yield parameters and highest net returns and B:C ratio. Straw mulching when done alone or when followed by one hand weeding were the next best treatments with respect to weed control efficiency, growth, yield and net returns of chilli.
Performance of some fodder legumes in rice fallows
(Kerala Agricultural University, 1993) Meera V Menon; Achuthan Nair, M
Soil-plant-shade interaction on the productivity of kacholam (Kaempferia galangal L.)
(Department of Agronomy, College of Horticulture, Vellenikkara, 2003) Hani Gangadharan; Meera V Menon