Browsing by Author "Sansamma George"

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Agronomic evaluation of biofarming techniques for forage production in coconut gardens
(Department of Agronomy, College of Agriculture, Vellayani, 1996) Sansamma George; Raghavan Pillai, G
Two field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala State to study the potential of biofarming techniques for forage production in coconut gardens. The study was carried out for a period of two years from September 1993 to August 1995. The influence of the different nutrient management techniques on uptake of nutrients, quality of produce and physico-chemical properties of soil was also investigated. In experiment no.1. the influence of two nitrogen fixing organisms., viz. Azospirillum and Azotobacter and the role of Vesicular Arbuscular Mycorrhiza (VAM) in improving the growth and production of guinea grass and congosignal was studied under inoculation alone and also in combination with chemical fertilizers. The nitrogen fixers were tested under varying levels of fertilizer nitrogen and for VAM the level of phosphorus varied between treatments. The prospects for vermicompost use for guinea grass production was examined under experiment no. 2. It was also envisaged to compare the impact of integrated use of manures and fertilizers with the continuous use of chemical fertilizers alone. Results of experiment no.1 revealed that Azospirillum inoculation alone and in combination with fertilizers had significant positive influence on guinea grass production. Azotobacter inoculation showed only limited effects on growth and yield of the forage grass during the first year but the effect was significant during the second year. The results indicated that 25 per cent of the recommended nitrogen could be saved through the use of either of the biofertilizers. VAM inoculation when combined with full dose of recommended fertilizer nitrogen and potassium, showed significant superiority over the POP treatment at 0, 25 and 50 per cent phosphorus doses while the 75 percent P dose gave comparable yields. The quality parameters of the forage recorded values on par or superior to that of the recommended fertilizer treatment. The use of biofertilizers improved the net income and benefit : cost ratio from guinea grass cultivation. The inoculation treatments were found to have a favourable influence on the physical and chemical properties of the soil. Integrated use of the nitrogen fixing organisms with chemical fertilizers was found effective for Congosignal cultivation. Pooled analysis studies indicated that when inoculated with either Azospirillum or Azotobacter, 50 per cent of the recommended fertilizer nitrogen was adequate for yields. VAM inoculation alone elicited significant yield increase over the absolute control. Combind doses of VAM with chemical fertilizers at all levels of applied phosphorus responded more or less similar to the recommended fertilizer treatment. This indicated the possibility of completely substituting the need for fertilizer phosphorus in VAM inoculated congosignal. The VAM effect in promoting growth and yield of the forage was found to decline in the presence of applied phosphorus. The data on economics also favoured the use of biofertilizers. Experiment no. 2 revealed that guinea grass responded well to integrated use of manures and fertilizers. As per pooled analysis vermicompost @ 5 t ha-1 or Farm yard manure @ 10 t ha-1 when combind with 75 per cent of the recommended NPK were comparable with the 100 per cent NPK treatment. Application of the organic manures improved the quality of the produce. The physic-chemical properties of the soil was also favourably influenced by the integrated use of manures and fertilizers. The economic analysis of the data emphasised the need for reducing the reliance on purchased inputs. Coconut yield was found favourably influenced by intercropping of the fodder grasses.
Effect of shade on growth, nodulation and yield of cowpea (Vigna unguiculata (L) walp)
(Kerala Agricultural University, 1987) Sansamma George; Vikraman Nair, R
Evaluation of new generation herbicides in transplanted rice (Oryza sativa.L)
(Department of Agronomy, College of Agriculture, Vellayani, 2013) Rajagopal, K; Sansamma George
An investigation entitled “Evaluation of new generation herbicides in transplanted rice (Oryza sativa L.)” was undertaken during December 2011 to April 2012. The main objectives were to evaluate the weed control efficiency of two new generation herbicides; ie;bensulfuron methyl + pretilachlor and azimsulfuron, in transplanted rice, to assess their selectivity and influence on growth and yield of rice, and to work out the economics. The design was Randomised Block Design and the treatments were , bensulfuron methyl + pretilachlor @ 45+450 g ai ha-1, 60+600 g ai ha-1 and 75+750 g ai ha-1, azimsulfuron @ 25 g ai ha-1, 30 g ai ha-1 and 35 g ai ha-1, hand weeding at 20 and 40 days after transplanting (DAT) and weedy check. The results indicated that both bensulfuron methyl + pretilachlor and azimsulfuron were broad spectrum herbicides. Bensulfuron methyl + pretilachlor, applied as pre emergence herbicide was found effective for controlling weed growth especially during the early crop growth stages and among the three doses tried, bensulfuron methyl + pretilachlor @ 75+750 g ai ha-1 was found performing better than the lower doses. The efficiency of azimsulfuron for managing weeds as a broad spectrum post emergence herbicide was evident from observations on 40 DAT, 60 DAT and at harvest stage. On 40 DAT azimsulfuron @ 35 g ai ha-1 recorded 100 per cent weed control efficiency and at later stages also it was superior to other treatments. Grain yield recorded was significantly higher under azimsulfuron @ 35 g ai ha-1. The next best treatment was hand weeding andit was followed by bensulfuron methyl + pretilachlor @ 75+750 g ai ha-1 and azimsulfuron @ 30 g ai ha-1. Straw yield also was highestin azimsulfuron @ 35 g ai ha-1 but it was on par with bensulfuron methyl + pretilachlor @ 75+750 g ai ha-1, hand weeding and azimsulfuron @ 30 g ai ha-1.The lowest grain and straw yield were recorded underweedy check. The net income under the herbicide treated plots was found to be substantially higher than that of hand weeding and weedy check. Among the various herbicide treatments, the best result was under azimsulfuron @ 35 g ai ha-1.The B: C ratio also confirmed the superiority of the new generation herbicides for weed management in transplanted rice. None of the treatments showed any phytotoxic symptoms on rice plants. The results on soil microbial population showed that the soil samples from the herbicide treated plots had a higher microbial population than that of the untreated plots. Overall inference from the study is that both azimsulfuron and bensulfuron methyl + pretilachlor are promising broad spectrum herbicides for transplanted rice.
Floristic diversity, autecology and competitive behaviour of weed flora in wetland rice ecosystem
(Department of Agronomy, College of Agriculture, Vellayani, 2010) Sajith Babu, D; Sansamma George
Floristic diversity, autecology and competitive behaviour of weed flora in the wetland rice ecosystem were studied by conducting a field survey and two field experiments. The field survey was conducted during the first and second crop seasons of 2003 in the rice fields of 30 panchayaths in Thiruvananthapuram district having more than 50 hectares of net sown area, covering all the four thaluks of the district. Weed flora was surveyed from both cultivated and fallow fields. The design adopted for conducting the floristic survey was Stratified Multistage Random Sampling and the methodology was Census Quadrate Method. The field experiments were conducted during the first crop seasons of 2003 and 2004 at College of Agriculture, Vellayani. The design adopted was Strip plot. The treatments included four levels of nutrient management and three levels of crop spacing and the number of replications was five. Part III of the investigation was an autecological study wherein the growth and development pattern of two of the major weed flora observed in the experimental area was studied by keeping an area of 1.2 X 4.2 m2 on the same side of all the plots in Part II. Perusal of the results of the field survey indicated that substantial diversity of weed flora existed in the wetland rice ecosystem in Thiruvananthapuram district of Kerala. In the cultivated rice fields, there were 46 weed specii during the first crop season and 49 species during the second crop season. In the rice fallows during the first crop season there were 43 specii while during the second crop season there were 54 specii. In the cultivated fields during both seasons, the most prominent species among the different classes of weeds (grasses, sedges and broad leaved weeds) were Isachne miliacea Roth ex Roem et Schult, Cyperus iria L. and Monochoria vaginalis (Burm.f.) Presl. Ex Kunth respectively. Isachne miliacea Roth ex Roem et Schult was the dominant grass weed in the fallows as well. However the dominant sedge weed in the fallows was Cyperus distans L.f. during the first crop season while it was Fimbristylis miliacea. during the second crop season. Monochoria vaginalis (Burm.f.) Presl. Ex Kunth and Ludwigia perennis topped the list of broad leaved weeds in the rice fallows during first and second crop seasons respectively. Results of the field experiment showed that weed growth in the rice field was influenced significantly by the sources and levels of nutrients as well as by crop spacing. During both the years at 20 and 40 DAT the weed density and dry weight were the lowest when the rice crop was treated with NPK @ 90:45:45 kg ha-1 applied with 25 per cent N as organic (N2) while at 60 DAT enhanced nutrient level (NPK @ 112.5:56:25:56.25 kg ha-1) applied with 25 per cent N as organic (N4) recorded the lowest value. During both the years, at all growth stages the weed density and dry weight were the lowest under the closer spacing of 15 X 15 cm (P1) The grain and straw yield were maximum under NPK @ 112.5:56:25:56.25 kg ha-1 applied with 25 per cent N as organic in combination with widest spacing (n4p3). Dead heart occurrence was minimum under the widest crop spacing The net income and Benefit : Cost ratio were the highest when rice crop was treated with 125 per cent of the recommended NPK with 25 per cent organic substitution in combination with widest spacing (n4p3) Autecological studies showed that the growth and development of Isachne miliacea Roth ex Roem et Schult. was significantly influenced by the management practices for the associated rice crop. The higher dose of NPK applied as chemical fertilizers only (N3) along with widest spacing (P3) stimulated all the vegetative parameters (shoot / root length and plant spread) of the weed. During both the years plants growing in rice fields treated with recommended dose of NPK with 25 per cent organic substitution (N2) and rice crop planted at wider spacing (P3) recorded delayed flowering but produced more seeds per panicle The root and shoot length of Cyperus iria L growing in rice fields treated with 100 per cent recommended NPK as chemical fertilizers (N1) with minimum spacing (P1) recorded the maximum value during the both years. Delayed flowering of the sedge was noticed under N2. The number of seeds produced per plant was significantly high under N4 and P3. The general trend was that addition of organic manures in rice delayed flowering but increased seed production in the associated sedge weed From the studies it may be concluded that by altering nutrient management and adjusting the plant population, the competitive ability and productivity of rice crop can be improved substantially. Though, closer spacing of 15 X 15 cm significantly reduced the density and dry weight of weeds, the wider spacing of 20 X 20 cm in conjunction with enhanced fertilizer dose of 112.5:56:25:56.25 kg NPK ha-1 applied with 25 per cent N as organic manures significantly enhanced the rice grain and straw yield. The treatment also resulted in significant enhancement in net income and B:C ratio in medium duration variety Aiswarya in first crop season.
Integrated weed management in brinjal (Solanum melongena L.)
(Department of Agronomy, College of Agriculture, Vellayani, 2000) Mandira Chakrabarti; Sansamma George
A field experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvanantbapuram to study the technical and economic feasibility of different weed management practices for brinjal. The study was carried out during the period from August to November, 1999. The experiment was laid out in Randornised Block Design with fourteen treatments and three replications. The treatments consisted of physical, cultural and chemical methods of weed control alone or in combination. Unweeded check and completely weed free check were included as control treatments. 'Swetha' was the variety of brinjal used for the study. Results of the study revealed that grasses, broadleaved weeds and sedges competed with the brinjal crop. The weed intensity and distribution was found significantly influenced by the weed management practices included in the study. It was evident that weeds failed to emerge under the black polythene mulching and the few weeds recorded were those emerging from the planting hole. There was no distinguishable weed growth even from the planting hole beyond 30 days after transplanting (OAT). The farmers practice of giving two manual weeding at 15 and 30 OAT allowed unchecked weed growth upto 15 OAT, but had comparatively high weed control efficiency at later stages. Application of fluchloralin as pre-plant incorporation (PPI) was found to inhibit early emergence of grasses and broadleaved weeds, but gave poor control of sedges. Fluchloralin + one hand weeding at 20 OAT was found to give season long control of weeds and was a better option than fluchloralin alone and fluchloralin + smother cropping. The cultural practices of stale seed bed technique and smother cropping gave early season weed control but allowed weed emergence later and gave improved weed control efficiency when integrated with one hand weeding. The effect of glyphosate application also was found to respond in similar lines. The weed management practices were found to exert considerable influence on growth and yield characters of the crop. Under weed free situation the plant produced the highest number of branches and leaves and had the maximum number of flowers and fruit also. The crop yield was found to bear a direct positive correlation with the weed control efficiency of the management practices. Weedy check recorded the lowest yield and the yield losses worked out was 58.43 per cent. Excluding the weed free check, the yield loss was minimum under black polythene mulching followed by fluchloralin + one hand weeding. The most remunerative treatment was found to be fluchloralin + one hand weeding (T9) followed by two manual weeding (T3). The herbicides were found non persistent leaving little toxic residue in the soil after the experiment.
Invasion impact of greater club rush (Scirpus grossus L.f) on wetland rice ecosystem
(Department of Agronomy, College of Agriculture, Vellayani, 2017) Gayathri Karthikeyan, P; Sansamma George
Investigation on allelopathic influence and control of purple nuts edge
(Department of Agronomy, College of Agriculture, Vellayani, 1999) Ameena, M; Sansamma George
Lab and field experiments were conducted at the Instructional farm, College of Agriculture, Vellayani to study the allelopathic influence of Purple nutsedge (Cyperus rotund us L) on important field crops; to investigate the effectiveness of systemic herbicides for control of nutsedge and also to assess the effect of chemical weed control on growth and yield of subsequent field crops. In Ex. no. I, allelopathic influence of purple nutsedge on important field crops like rice, ragi, cowpea, green gram, bitter gourd and bhindi were studied. The treatments comprised of aqueous extracts and blended extracts of fresh and dry plant parts of nutsedge. The results revealed that aqueous extracts of nutsedge inhibited germination of rice, ragi, bitter gourd and bhindi while it had some stimulatory effect on germination of cowpea and green gram. The early growth characters of the field crops were found suppressed by the aqueous extract treatment while the blended extract showed no effect. In general, the dry plant parts showed greater effect than the fresh material. Under Ex.no.Il, field studies were made to investigate the effectiveness of systemic herbicides viz. Glyphosate and 2,4-D for control of nutsedge. The treatments included different doses of the herbicides with and without adjuvants and Glyphosate combined with sublethal dose of 2,4-D. The results revealed that lowest dose of the herbicides were sufficient for complete kill of the purple nutsedge plants in the experimental area and there was no regrowth upto 6 weeks. There was significant reduction in viability of tubers collected one month after herbicide application, but the tubers tested 45 days after spraying showed an increase in germinability over the record on 30th day. Tubers from treatments involving Glyphosate with sublethal dose of 2,4-D recorded the lowest sprouting percentage indicating the possibility for weed control for a longer period. In Ex. no. In, the persistence of the herbicides in soil were monitored and it was observed that early growth of cucumber sown on the same day of herbicide application was affected while that sown on soils collected 10 days after spraying recorded growth characters comparable to that of control. From Ex.no.IV, it could be inferred that chemical weed control did not show any deleterious effect on growth and yield characteristics of ragi and cucumber sown 15 days after the treatments. Application of 2,4-D for nutsedge control was found superior to other treatments in terms of net income and B:C ratio and the lower unit cost of the chemical was precisely the reason for its superiority.
Investigations on the allelopathic influence of eupatorium (Chromolaena odorata(L.) King and Robinson and utilization as organic manure
(Department of Agronomy, College of Agriculture, Vellayani, 2002) Navaz, M; Sansamma George
Lab and field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani during June 2001 to February 2002 to study the allelopathic influence of eupatorium (Chromolaena odorata (L.) King and Robinson) on important field crops and weed species and to investigate the potential of the weed biomass as organic manure. In Experiment I, allelopathic influence of eupatorium on three important field crops ie., rice (Oryza sativa L.), cowpea (Vigna unguiculata (L.) Walp.) and Bittergourd (Momordica charantia L.) and two weed species. ie ., Thatch grass (lmperata cylindrica (L.) Beauv.) and eupatorium (Chromofaena odorata (L.) King and Robinson) was studied. The treatments comprised of aqueous plant part leachates of fresh and decayed eupatorium at five and ten per cent co ncentr at io n. The results revealed that aqueous fresh plant part leachates inhibited germination and early seedling growth of rice, cowpea and bittergourd severely. Germination of thatch grass and eupatorium were also suppressed by the treatments. In general, the aqueous fresh plant part leachates showed greater effect than the decayed plant part leachates, and the effect was more -with leaf leachate. The inhibitory effect was more with the higher concentration of the leachate. Under Experiment II, field observations were made to study the biology of eupatorium under Kerala conditions. Composting of mature eupatorium was tried and the response of bhindi to eupatorium as compost and green leaf manure was observed in comparison with poultry manure, vermicompost, coirpith compost and farmyard manure. The results revealed that eupatorium took about 293 days from germination to seed maturity under Kerala conditions. The plant flowering was during December - January and seeds dispersed in the months of February - March. Each plant produced about 25,000 seeds on an average and had a germination percentage of about 30 per cent. When the mature and dried eupatorium weed biomass was composted, the C : N ratio came down from 62.72 to 18.88 in four months and was ready for use as organic manure. The NPK content of the composted material was 0.76, 0.58 and 0.81 per cent respectively. The yield response of bhindi to eupatorium as organic manure revealed that eupatorium compost was on par with poultry manure and farmyard manure treatments. However when the fresh weed biomass was used as green leaf manure, the yield was considerably lower. The results indicated the need and usefulness of composting the weed biomass before using it as sole source of organic manure in bhindi.
Management of blood grass(isachne miliacea roth ex roem et schult) in wetland rice ecosystem
(Department of Agronomy, College of Agriculture, Vellayani, 2018) Renjan, B; Sansamma George
Management of greater club rush (Scirpus grossus L.f) in wetland rice ecosystem
(Department of Agronomy, College of Agriculture, Vellayani, 2011) Sreethu, G S; Sansamma George
An investigation entitled“ Management of greater club rush (Scirpus grossus L.f) in wetland rice ecosystem’’was undertaken in a wetland rice ecosystem heavily infested with the weed. The study was taken up during February 2010 to January 2011. The main objectives of the experiment were to develop a management strategy for recovering the wetland rice ecosystem invaded by greater club rush, economical analysis of rice cultivation in the land recovered from the invaded weed and study of the weed biology. Laboratory studies conducted at College of Agriculture, Vellayani, were also included to achieve the objectives envisaged. The field experiment on weed management (part I) was laid out in Randomised Block Design with nine treatments and three replications. The treatments included farmer’s practice of tillage, application of lime at two different doses after tillage and application of glyphosate and 2, 4 – D alone and in combination on weed re-growth with and without tillage. Before applying the treatments, the thick growing weed was given an initial mowing. The laboratory studies were done to analyse the herbicide residue in the treated plots and to study the effect of the applied herbicides on the soil microbial population. The treatment adjudged as the most efficient was verified further in a larger plot, by comparing it with the farmer’s practice of weed management to study the economics of rice cultivation in the land recovered from the invasive weed (part II). The biology of greater club rush was also studied simultaneously (part III). The results of the weed management study indicated that all the herbicidal treatments were significantly superior to farmer’s practice of tillage in reducing the weed dry weight. Weed control efficiency was found to be 100 percent throughout the study, when the thick infestation was mowed once and treated with a combination of (glyphosate @1kg ai ha-1 + 2,4-D @ 2 kg ai ha-1) Tillage + glyphosate @1kg ai ha-1 + 2,4-D @ 2 kg ai ha-1 was also effective in controlling the weed, but fragments of root system was found remaining in the soil even after nine months; as a possible source of reinfestation. However, application of lime as a means of controlling greater club rush was found to have no effect on the weed growth. Considering all factors, T7 (glyphosate @1kg ai ha-1 + 2,4-D @ 2 kg ai ha-1) was adjudged as the best treatment for testing further in the farmer’s field (part II ). There was substantial increase in the floristic diversity after the experiment in herbicide treated fields which were completely cleared of greater club rush within 45 days of herbicide application. The residue analysis of the soil collected on the next day of herbicide application revealed that the residue was below detectable limit in the case of both 2, 4 – D and glyphosate, alone as well as in combination. The results on soil microbial population indicated that the soil treated with any of the herbicides had a much higher microbial population than the untreated plots. The cost worked out for the management of the thick infestation of greater club rush was prohibitively high in all the treatments. Economic analysis of rice cultivation in the land recovered from the invasive weed indicated that the grain and straw yield in the treated plot was substantially higher than that from the non treated plots. When the economics was worked out inclusive of the cost of land recovery through eradication of greater club rush, the net profit from rice cultivation was not very high. But the important indication was that the farmers suffered great loss when they followed the present practice of mowing followed by tillage. The observations on the weed biology indicated that in greater club rush, propagation was exclusively through vegetative means. The nutrient composition of the weed was comparable to that of rice plant. Due to its very high biomass production, the nutrient uptake of greater club rush was much higher than that of rice crop.
Management of water cabbage (Limnochairs flava (L.) buchenau) in wetland rice ecosystem
(Department of Agronomy, College of Agriculture, Vellayani, 2012) Nishan, M A; Sansamma George
An investigaton entitled ‘Management of water cabbage (Limnocharis flava (L.) Buchenau) in wetland rice ecosystem’ was carried out in the wetland of the Instructional farm attached to the College of Agriculture, Vellayani from February 2011 to January 2012. The major objectives of the experiment were, to study the biology of water cabbage (Limnocharis flava (L.) Buchenau), to evaluate certain new generation herbicides for managing it and to assess the potential of the weed biomass as an organic source. For the study of weed biology (Part I), a part of the weed infested field was selected for the experiment and prepared thoroughly as in the case of rice cultivation and the sample plants were observed from their emergence onwards. The ontogeny of the weed, its vegetative, and reproductive characters and also their allelopathic influence on germination and early growth of rice were studied. The field experiment on weed management (Part II) was laid out in Randomised Block design with eight treatments replicated thrice. The treatments included azimsulfuron @20 and 30 g a.i. ha-1, bispyribac sodium @20 and 30 g a.i. ha-1), (metsulfuron methyl+ chlorimuron ethyl) @ 4 and 6 g a.i. ha-1 and 2, 4-D @ 1 kg a.i. ha-1 along with a weedy check as control. The potential for utilization of the weed biomass through vermicomposting (Part III) was also assessed during the investigation. The data on weed biology indicated that water cabbage had very efficient reproductive mechanism which explains the invasive nature of the weed. A single plant was found capable of producing more than one lakh seeds and about 90 per cent of them germinated under favourable conditions. The plants exhibited pseudovivipary, through production of ramets which gave an additional advantage for the plant to spread. Germination studies revealed that maximum weed seed germination occurred under direct sunlight in crowded condition in the wetland soil condition. Direct sunlight was found necessary for the seed germination. Allelopathic studies showed that the fresh leachate of water cabbage was found to exert a positive effect on the vigour index of rice seedlings while substantial reductions in seedling growth were observed when treated with decayed plant leachate. The results of the field study on weed control efficiency of the different herbicides indicated that 2, 4-D @1 kg a.i. ha-1 was most effective for controlling water cabbage. Among the new generation herbicides (metsulfuron methyl + chlorimuron ethyl) @ 6 g a.i. ha-1 and bispyribac sodium @ 30 g a.i. ha-1 were equally effective for controlling water cabbage. The results of soil microbial studies indicated that the soil treated with the herbicides had much higher microbial population than the untreated plots except in the case of bispyribac sodium. The cost of managing the weed by using new generation herbicide was found considerably lower than that by manual weeding. The chemical analysis of the vermicompost prepared from the weed biomass recorded favourable nutrient composition. The micronutrients and heavy metals were within the safe limits except for the copper content. More over, the luxuriantly growing weed biomass was promising for bioremediation, to remove pollutants from aquatic ecosystems.
Performance evaluation of certain rice cultivars
(Kerala Agricultural University, 1993) Susamma P George; Devadas, V S; Sansamma George; Pillai, G R
Experiments were conducted with 12 rice cultivars for three consecutive years from 1984-85 to 1987-88 during kharif and rabi seasons in randomised block design. Pooled analysis of the data for kharif and rabi seasons indicated that MO 4 registered the highest grain yield in the kharif (5068 kg/ha) and rabi (4891 kg/ha) crop seasons. Hence MO 4 can be recommended for cultivation in Wynad in both the seasons. Edavaka was also found to be a promising cultivar when grain yield, straw yield and comparatively shorter duration were considered and hence requires further studies.
Shade response of common rainfed intercrops of coconut part II legumes
(Department of Agronomy, College of Horticulture, Vellanikkara, 1982) Sansamma George; Vikraman Nair, R
The experiment was laid out in randomised block design with four levels of shade and five replications. The study revealed that all the legumes tried viz., cowpea, blackgram, groundnut and redgram, were all shade sensitive.
Weed control in wetland rice in the high ranges of Wynad
(Kerala Agricultural University, 1993) Sansamma George; Aipe, K C; Susamma P George; Pillai, G R; Balakrishna Pillai, P
A field investigation was carried out at the Regional Agricultural Research Station, Ambalavayal, Wynad, Kerala for evaluating some of the herbicides for weed control in rice and also to standardise the best time of hand weeding for rice in Wynad. Four herbicides, alone and in different combinations and also two different time of hand weeding were compared. The results indicated that use of herbicides for weed control in rice was economically advantageous for the high ranges of Wynad. Though not statistically significant, hand weeding on 30th and 60th days after transplanting (DA I) was found superior to hand weeding at 20th and 40th DAT both in terms of weed control and yield.