Browsing by Author "Syama S Menon"

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Agrotechniques for mitigating water stress in vegetable cowpea (Vigna unguiculata (L.) Walp.)
(Department of Agronomy, College of Horticulture,Vellanikkara, 2016) Syama S Menon; Savithri, K E
Water stress is one of the major abiotic stresses that limits crop production. Vegetable cowpea is an important non season bound crop in Kerala and water scarcity limits its area under cultivation during summer season. Research reports indicate that water stress in crop plants can be mitigated by foliar spray of plant growth regulators, seed hardening mulching, antitranspirant sprays and nutrient management. However, research works in this line in Kerala are meagre. Hence a study was taken up to develop a package for mitigating water stress in summer vegetable cowpea by assessing the effect of above practices on the growth and yield of the crop. Field experiments were conducted during the summer season (Jan-Mar) of 2014 and 2015, using the variety Kashi Kanchan. There were three experiments during the first year to evaluate the effect of (1) exogenous application of plant growth regulators (PGRs), (2) seed priming, antitranspirant sprays and soil moisture conservation practices, and (3) nutrient management practices for mitigating water stress in vegetable cowpea. The best treatments from each of the first year experiments were selected and their effects independently and in combinations were evaluated in an experiment during the second year of study. The first experiment was done to evaluate the effect of various plant growth regulators in mitigating water stress in vegetable cowpea. Among the treatments, farmers practice (irrigation at 2 days interval) recorded the highest growth and yield and absolute control the lowest. Among plant growth regulators, salicylic acid 2 per cent and NAA 40 pm recorded higher growth and yield by way of their favourable influence on mitigating water stress. The second experiment was conducted to evaluate the effect of seed priming, mulching, and antitranspirant sprays in mitigating water stress. The results showed that, among seed primers, , seed hardening with 0.5 per cent NaCI recorded better growth and yield of cowpea compared to that with 2 per cent CaCl2 and per cent KH2PO4 due to the comparatively better efficacy of sodium chloride in equipping the cowpea plants for drought tolerance. Mulching with polythene and plant residues were equally effective in recording better plant growth and yield due to their favourable influence on soil moisture availability. Among anitranspirants, foliar spray of lime water as 2 per cent Ca(OH)2 during the water stress imposed period resulted in better growth and yield of cowpea plants due to increased albedo. The third experiment was conducted to evaluate the effect of various nutrient management practices in mitigating water stress. The results revealed that among nutrient managements practices, foliar spray of 2 per cent DAP+I Per Cent KCL, 0.5 per cent ZnSO4 and seed treatment with PGPR mix I+ rhizobium were better in attaining higher growth and yield under water stress. In the second year, the best treatment from each of the first year experiments were selected and their independent and combinations were evaluated. In general, plant growth was higher higher in all mulched treatments, either alone or in combinations, NaCL+PRM+ (PGPR mix 1+rhhizobium)+ Zinc sulphate recorded the highest growth yield income ,net profit (Rs.2,03,389/-) and B:C ratio ( 4.1) which was even higher than farmers practice. Plant residue mulching alone also recorded higher yield and B:C ratio than farmers practice which showed the significant influence of mulching in mitigating water stress. Among the independent treatment, foliar spray of either Zinc sulphate or salicylic acid was found better compared to others in terms of growth and yield of vegetable cowpea.
Efficacy of new post-emergence herbicides for rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 2012) Syama S Menon; Prameela, P
Weeds are the major problem in rice production. Manual removal of weeds is laborious and due to labour shortage and high cost of labour, farmers are resorting to chemical weed control. Many new molecules of selective herbicides are now coming in the market which are having broad spectrum activity or effectiveness against a group of weeds. The present study was conducted to evaluate the relative efficacy of some of these herbicides in wet land rice culture. The experiment was conducted at Alappad Kole in farmer’s field during October 2011 to February 2012. The treatments included application of graminicides alone ( metamifop, fenoxaprop p-ethyl, cyhalofop-butyl); graminicides with follow up application of herbicides to kill non grass weeds (cyhalofop-butyl fb Almix, metamifop fb carfentrazone ethyl, metamifop fb Almix, fenoxaprop p-ethyl fb Almix, fenoxaprop p-ethyl fb ethoxysulfuron) and herbicides with broad spectrum activity (bispyribac sodium, penoxsulam and azimsulfuron). Hand weeded and unweeded controls were also included for effective comparison. All herbicides in the study were post emergent in action and were sprayed at 20 DAS. Observations on weeds as well as crop were taken at 30 DAS, 60 DAS and at harvest. Visual phytotoxicity scoring on rice as well as on weeds was done at three and seven days after spraying. As revealed by the weed spectrum in unweeded control, grasses were the dominant weeds than sedges and broad leaved weeds. Among grasses, Echinochloa stagnina and Echinochloa crusgalli among sedges Fimbristylis miliacea, Cyperus iria and Cyperus difformis and in broad leaved weeds Lindernia crustacea and Ludwigia perennis were the dominant weed species. Sedges and broad leaved weeds were present in treatments applied with graminicides alone at 30 DAS. At 60 DAS and at harvest, higher weed population was observed compared to 30 DAS. Bispyribac sodium, cyhalofop-butyl+Almix and fenoxaprop p-ethyl+Almix continued to perform better in terms of weed control as evidenced by low weed dry matter production both at 60 DAS and at harvest. N, P and K uptake by weeds at different stages of crop followed the same trend as that of weed dry matter production. Among various herbicides or herbicide combinations only carfentrazone ethyl applied treatment showed phytotoxicity to rice. The variations in plant height among treatments were significant only at 30 DAS and the tallest plants with 54 cm height were observed in unweeded control. However, there was a slight reduction in the height of rice in plots applied with Almix, fenoxaprop p-ethyl and bispyribac sodium compared to hand weeded control, though visual phytotoxicity symptoms were not expressed. The highest number of panicles/m2, filled grains per panicle as well as grain yield was registered in hand weeded control. Cyhalofop-butyl+Almix and fenoxaprop p-ethyl+Almix were on par with respect to grain yield and recorded comparable yield with that of hand weeding. Cyhalofop-butyl+Almix and fenoxaprop p-ethyl+Almix also registered low weed index of 5.2 (for both) and high weed control efficiency of 88 and 90 percent, respectively. From this study it can be concluded that, cyhalofop-butyl followed by Almix or fenoxaprop p-ethyl followed by Almix or bispyribac sodium alone can be recommended for effective post emergence weed control and higher yield in wet seeded rice. If grasses are the predominant weeds, cyhalofop-butyl or fenoxaprop p-ethyl alone without follow up spray of Almix can also be recommended.
Nutrient management in finger millet (Eleusine Coracana (L) Gaertn)
(Department of Agronomy, College of Agriculture, Vellanikkara, 2024-02-15) Ribin Usman, T; Syama S Menon
The study entitled “Nutrient management in finger millet [Eleusine coracana) (L.) Gaertn.].” was undertaken at the Agronomy Farm, College of Agriculture, Vellanikkara during October 2021 to February 2022. The objective of the experiment was to standardize the optimum nutrient dosage for maximum growth and yield of finger millet. The experiment was laid in randomized block design with eight treatments with replicated thrice. The plot size was 4.8 m x 4 m and transplanting were done at a spacing of 30 cm x 10 cm. The treatment included different levels of nutrients which was compared with an absolute control (T1–5 t FYM ha-1 ,T2–5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1, T3-5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1, T4- 5 t FYM ha-1 + 50: 25: 25 kg NPK ha-1, T5- 5 t FYM ha-1 + 40: 20: 20 kg NPK ha-1, T6- 5 t FYM ha-1 + 30: 15: 15 kg NPK ha-1, T7- 5 t FYM ha-1 + 20: 10: 10 kg NPK ha-1). The ragi variety used for the study was Hima. The results of the experiment revealed that plant height washigher in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1at 30 DAT (75.33 cm), flowering (76.63 cm) and harvest (77.90 cm) which was on par with 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1and 5 t FYM ha-1 + 50: 25: 25 kg NPK ha-1.Significantly higher leaf area index recorded highest in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 (2.91). Higher number of fingers per panicle, weight of grains per panicle and dry mater production (at 30 DAT, flowering and harvest) also showed the same trend with significantly highest values in higher level of fertilizer dose (5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1). Significantly highest yield was recorded in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1(1523 kg ha-1) followed by 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1,. Similarly highest straw yield was also noticed in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1(2568 kg ha-1) followed by 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1, which was on par with other lower dose of fertilizers. This is due to, increased availability of the nutrients in the root zone enabled higher uptake of the nutrient and it led to a better nutrient status in plant system. On the other hand, the increased net photosynthesis and increase in mobilization of photosynthates toward the reproductive structure contributed to grain yield. Crude protein content, even though significantly different, the values are on par with different levels of fertilizer doses and recorded higher in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1, 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1 and t FYM ha-1 + 50: 25: 25 kg NPK ha-1 than absolute control. This can be due to higher nitrogen contents present in these treatments as evidenced by the higher N uptake values.Calcium content in the grain was highest in 5 t FYM ha-1(431.6 mg 100 g-1) and showed a reduced content in5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 (419.4 mg 100 g-1). Iron and fibre content was not influenced by application of nutrients levels. Nitrogen, phosphorus and potassium uptake by ragi was highest in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 (59.58, 31.39 and 65.73 kg ha-1 respectively). It followed the same trend as that of dry matter production. The available nutrient status in the soil after the experiment in general showed a decrease due to plant utilization.P status varied significantly with treatment combination, while the changes in available N and K were not significant. Available phosphorus content was recorded highest in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1(75.13 kg ha-1), Highest net income (Rs. 28,355 ha-1) and BC ratio(1.43) was obtained in5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 due to maximum yield compared to other nutrient levels. From the results it can be concluded that application of FYM @5 t ha-1as basal and NPK @90: 45: 45 kg ha-1, where full dose of P and K along with half dose of N applied as basal and the remaining half of N applied 30 DAT will result in higher yield and net returns. Hence, can be recommended for the high yielding finger millet variety Hima in AEU 10 (North Central Laterite of Kerala) and multi location trials are required to arrive at a final recommendation.