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Open Access
Effect of secondary nutrients on yield and quality of turmeric (Curcuma longa L.)
(Department of Agronomy, College of Horticulture, Vellanikkara, 2014) Sanghamithre, V K; KAU; Meera, V Menon (Guide)
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.
Open Access
Production technology of chilli (Capsicum annum L.) under protected cultivation
(Department of agronomy, College of agriculture, Vellayani, 2014) Pintu Roy, Vattakunnel; KAU; Sajitha Rani, T
The field experiment entitled “Production technology of chilli (Capsicum annuum L.) under protected cultivation” was conducted at Instructional Farm, College of Agriculture, Vellayani during March 2013 to September 2013 to study the performance of chilli varieties and the effect of fertigation on productivity of chilli (Capsicum annuum L.) under protected cultivation. The main plot treatments were a combination of growing conditions (poly house and open field) and fertigation (with fertigation and without fertigation) and the subplot treatments consisted of three varieties (Vellayani Athulya, Anugraha and Jwalamukhi). The study revealed that plants grown under poly house situation recorded significantly higher fruit length (11.77cm), number of fruits plant-1 (110.67), fruit yield plant-1 (604.08 g) and total fruit yield (29.54 t ha-1). Plants grown with fertigation registered higher number of fruits plant-1 (113.49), length of fruit (11.55 cm), fruit yield plant-1 (591.92 g) and total fruit yield (26.27 t ha-1). Maximum length of fruits (12.82 cm), fruit yield plant-1 (665.18 g) and total fruit yield (28.41 t ha-1) were obtained from Vellayani Athulya while, highest number of fruits plant-1 (154.21) was from Anugraha. Maximum length of fruits was observed in Vellayani Athulya grown under both poly house (12.91 cm) and open field situation (12.72 cm). Vellayani Athulya grown with fertigation also recorded maximum fruit length (13.67 cm). Vellayani Athulya recorded maximum shelf life (10.19 days) and ascorbic acid content (98.71 mg 100 g-1) where as maximum capsaicin content (1.38 per cent) was recorded by Jwalamukhi. Vellayani Athulya grown under poly house registered maximum shelf life (10.88 days) and ascorbic acid content (102.78 mg 100 g-1). Vellayani Athulya with fertigation recorded maximum ascorbic acid content (101.69 mg 100 g-1) while, Jwalamukhi grown with fertigation recorded maximum capsaicin content (1.40 per cent). Vellayani Athulya grown under poly house with fertigation recorded higher shelf life (12.00 days). Vellayani Athulya grown under poly house with fertigation recorded maximum ascorbic acid (108.74 mg 100 g-1). Maximum capsaicin was also recorded by Jwalamukhi grown under poly house with fertigation (1.43 per cent). Among growing conditions, maximum net return (Rs 5.22 lakhs ha-1) and B: C ratio (2.42) was obtained from poly house. On comparing with and without fertigation treatments, with fertigation treatments recorded maximum net return of Rs 4.46 lakhs ha-1 and among varieties, Vellayani Athulya (V1) recorded maximum net return of Rs 4.95 lakhs ha-1 and B: C ratio of 2.30.
Open Access
Need based nitrogen management in rice (Oryza sativa L.) using diagnostic tools
(Department of Agronomy, College of Agriculture, Vellayani, 2014) Palle Pavan Kumar, Reddy; KAU; Meerabai, M
An investigation entitled “Need based nitrogen management in rice (Oryza sativa L.) using diagnostic tools” was carried during the Virippu season (first crop season), 2013 at farmer’s field, Kalliyoor Panchayath, Thiruvananthapuram district, Kerala state. The main objectives of the experiment were to study the technical and economic feasibility of using chlorophyll meter (SPAD meter), leaf colour chart (LCC) and soil testing kit for assessing the crop nitrogen status, to schedule N application in rice based on crop need and to work out the economics. The field experiment was laid out in Randomised Block Design (RBD) with three replications. The treatments were N application at LCC value 3.0, 4.0 and 5.0, N application at SPAD value 32, 34 and 36, N application based on soil test value using soil testing kit, KAU POP and absolute control. N application at LCC value 5.0 and N application based on soil test value recorded significantly superior values for plant height, LAI, number of tillers per hill, dry matter production, number of productive tillers/m2, higher straw yield, higher uptake of N, P and K and total chlorophyll of leaves. N application based on soil test value recorded higher gross income. N application at LCC value 4.0 and SPAD value 36 recorded higher values for grain weight/panicle, filled grains/panicle, thousand grain weight, net income and B:C ratio. Sterility percentage was also minimum for N application at LCC value 4.0, SPAD value 36 and KAU package of practices. N application at SPAD value 36 and LCC value 4.0 recorded significantly higher grain yield, harvest index, agronomic efficiency, physiological efficiency and apparent recovery efficiency. The grain yield with SPAD- 36 and LCC- 4 which received 70 kg N/ha were on par with KAU POP which received 90 kg N/ha in 3 splits. Hence a saving of 20 kg N/ha was achieved with a higher yield compared to POP. The nutrient status of the soil after the experiment did not show any significant difference except in organic carbon content. The organic carbon recorded was significantly higher under KAU package of practices. The partial factor productivity and internal utilization efficiency decreased with increase in the total amount of N applied due to higher input cost on fertilizer or less grain yield. The relationship between SPAD values and LCC scores was found to be linear. It can be concluded from the present study that the rice variety Uma performed best with application of 20 kg N/ha as basal and 25 kg N/ha each applied as top dressing at 40 and 60 DAT (based on LCC-4 or SPAD-36). P and K were applied as per KAU POP. Thus the use of LCC or SPAD meter are efficient tools which helped in reducing the recommended dose of N from 90 kg/ha to 70 kg/ha. Since, the high cost of chlorophyll meter keeps it out of reach of many farmers, the leaf colour chart (LCC) is an inexpensive alternative to the chlorophyll meter. Hence, the LCC based N management is the better option than SPAD based N management practices in farmer’s point of view.
Open Access
Strategies for off season production of Coleus in the Southern zone of Kerala
(Department of Agronomy, College of Agriculture, Vellayani, 2014) Anju, V S; KAU; Kumari Swadija, O
A field experiment entitled “Strategies for off season production of coleus in the southern zone of Kerala” was undertaken at Instructional Farm, College of Agriculture, Vellayani from November 2013 to May 2014. The objectives of the study were to fix the ideal time of planting and nutrient management for off season production of coleus var. Suphala and to work out the economics of cultivation. The treatments consisted of four dates of planting (d1-November 15; d2-December 1; d3-December 15 and d4-January 1) and three nutrient management practices (n1-Recommended dose - 60:60:100 kg NPK ha -1 through fertilizers; n2-RD through organic manures -6 t farmyard manure + 3 t coir pith compost + 3 t wood ash per ha+ PGPR mix1 and n3-Modified nutrient dose -60:30:120 kg NPK ha -1 through fertilizers). The experiment was laid out in split plot design assigning dates of planting in main plots and nutrient management practices in sub plots with four replications. A uniform dose of FYM @ 10 t ha-1 of and of neem cake @ 1 t ha-1 was applied to all plots. Among four dates of planting tried, planting on November 15 (d1) recorded taller plants, higher number of branches and leaves per plant and higher leaf area index. Yield components like number and weight of tubers per plant were maximum when planted on November 15 (d1) followed by planting on December 1 (d2). Number and weight of marketable tubers per plant showed a decreasing trend when planting was delayed beyond November. The tuber yield also exhibited a similar trend recording the highest tuber yield of 14.89 t ha-1 for November 15 planting and the lowest tuber yield of 10.71 t ha -1 for January 1 planting. The tuber yield was significantly and positively correlated with the total rainfall received during the cropping period. Planting on November 15 recorded the highest utilization index. Total dry matter production and uptake of N, P and K were maximum when the crop was planted on November 15 and it showed a declining trend due to late planting. But quality attributes of tuber were not significantly influenced by date of planting. The highest net income (Rs.167525 ha -1) and BCR (1.84) were obtained by planting on November 15, which decreased with delay in planting. Modified nutrient dose of 60:30:120 kg NPK ha-1 through fertilizers (n3) significantly promoted all the growth characters. Higher number and weight of tubers as well as marketable tubers per plant were recorded by the same treatment which resulted in the highest tuber yield of 14.36 t ha -1. The same trend was noticed in the case of total dry matter production, utilization index, uptake of nutrients and starch content of the tuber. Significantly higher net income (Rs.163900 ha -1) and BCR (1.84) were recorded by the modified nutrient dose (n3) followed by recommended dose of nutrients through fertilizers (n1). Regarding interaction effects, November 15 planting with modified nutrient dose recorded significantly taller plants with higher leaf area index during later stages of crop growth. Similarly, the same interaction produced the highest number of marketable tubers per plant and tuber yield. November 15 planted crop with modified nutrient dose registered the highest net income and benefit cost ratio. Soil analysis after the experiment indicated higher pH and organic carbon contents and lower available N, P and K contents in organically manured plots than fertilizer applied plots. The study revealed that for off season production of coleus var. Suphala in the southern zone of Kerala, the ideal time of planting is November 15 which recorded higher tuber yield, net income and benefit cost ratio. Modified nutrient dose of 60:30:120 kg NPK ha-1 through fertilizers + FYM @ 10 t ha-1 + neem cake @ 1 t ha-1 can be recommended for the crop for getting higher tuber yield, net income and benefit cost ratio.
Open Access
Productivity enhancement in medicinal rice (Oryza sativa L.) cv. njavara
(College of Agriculture, Vellayani, 2014) Jyolsna, Bhaskaran; KAU; Pushpakumar, R
The present investigation on “Productivity enhancement in medicinal rice (Oryza sativa L.) cv. Njavara” was conducted at College of Agriculture, Vellayani for assessing the impact of silicon, modified NK ratios and reduced seed rate on the growth, lodging and yield and the economics of production of Njavara rice. The treatments consisted of three rates of silicon, viz, (S1)-0 kg, (S2)-50 kg and (S3) -100 kg Si02 ha-1.,three seed rates as (R1)-50 kg, (R2)-75 kg and R3- 100 kg ha-1 and three levels of K(modified N:K ratios) as K1- 40 kg(1:1),K2- 80 kg(1:2) and K3-120 kg(1:3) K20 ha-1.The experiment was laid out in split plot design with three replications. It includes 9 main plot treatments as combinations of silicon and seed rate (SR) and 3 sub plot treatments as the levels of K (modified N: K ratios). The results of the investigation are summarised below. Application of silicon influenced the growth attributes like plant height at 40DAS and at harvest, LAI at panicle initiation stage and culm strength at harvest stage. The other growth attributes like rooting depth, tillers m-2 and total biomass were not significantly influenced by silicon. Yield contributing characters like productive tillers m-2; spikelets panicle-1 and thousand grain weight were significantly influenced by silicon application. While silicon @100 kg ha-1 recorded significantly higher number of productive tillers m-2 and thousand grain weight, silicon @50 kg ha-1registered the highest number of spikelets panicle-1. The other yield contributing characters like grain weight panicle-1, filled grains panicle-1, sterility percentage, straw yield, grain yield and harvest index were not significantly influenced by silicon. Seed rate produced significant influence on growth attributes like plant height, LAI, total biomass and rooting depth. Seed @ 50 kg ha-1 produced the highest rooting depth and total biomass and seed @75 kg ha-1 produced highest plant height. Tillers m-2 and culm strength were not significantly influenced by seed rate. Yield attributes like number of productive tillers m-2, thousand grain weight, grain yield, straw yield and harvest index were significantly influenced by seed rate. While seed @100 kg ha-1produced significantly highest number of productive tillers m-2, thousand grain weight, grain yield, straw yield and harvest index were highest at seed @ 50 kg ha-1. Potassium (NK ratio) could not exert any significant influence on growth characters except plant height and number of tillers m-2, registering the superiority at K2 (N:K: 1:2). Number of productive tillers m-2 was the only yield contributing parameter significantly influenced by NK ratio ( K levels ) and the highest value was recorded by K3 (N:K: 1:3). Yield attributes like number of productive tillers m-2, grain yield, net income and B: C ratio varied significantly by interaction of treatments and s2 r3 k2 (S-50 kg ha-1, R-100 kg ha-1, NK 1:2 -80 kg ha-1) registered the highest grain yield. The highest net income and the highest B: C ratio of Rs 93120/- and 1.97 respectively were for s1r2k1. (S-0, R-75 , K-40 kg ha-1). Considering the general performance of the crop with regard to all the growth and yield parameters, the treatment receiving silicon @ 50 kg ha-1, seed @ 100 kg ha-1 and potassium @ 80 kg K2O ha-1(NK ratio 1:2) was found beneficial for Njavara rice.
Open Access
Evaluation of the new generation herbicide penoxsulam in transplanted rice(Oryza sativa L.)
(College of Agriculture, Vellayani, 2014) Sasna, S; KAU; Elizabeth, K Syriac
The study entitled “Evaluation of the new generation herbicide penoxsulam in transplanted rice (Oryza sativa L.)” was conducted during the period, December 2012 to April 2013 at farmer’s field in Nemom block, Thiruvananthapuram district. The objective of the study was to assess the bio-efficacy of the post emergence micro herbicide penoxsulam in transplanted rice and to work out the economics. The experiment was laid out in randomised block design with eight treatments and three replications. Four doses of penoxsulam i.e. 17.5, 20.0, 22.5 and 25.0 g a.i ha-1 (T1 - T4 ), bispyribac sodium @ 30.0 g a.i ha-1 (T5 ), 2, 4 –D sodium salt @ 1 kg a.i ha-1 (T6), hand weeding twice (T7) and weedy check (T8) constituted the treatments. Study of the weed flora dynamics of experimental field indicated the dominance of broad leaved weeds (7 sp.), followed by sedges (3 sp.) and grasses (2 sp.) All the herbicide treatments reduced the population and biomass of weeds substantially over weedy check. The lowest density and dry weight of weeds and highest weed control efficiency was recorded with penoxsulam @ 25.0 g a.i ha-1 (T4) at all the stages of observation, viz., 20 DAT, 40 DAT and 60 DAT. With respect to density of weeds, T4 was found to be on par with T3 at 20, 40 and 60 DAT. Regarding dry weight of weeds, at 20 DAT, T4 was on par with T3 ; however, at 40 DAT, all other herbicide treatments were on par with T4. None of the herbicides produced any phytotoxic symptom on rice plant. Critical analysis of the growth factors indicated the favourable effect of weed control treatments especially penoxsulam @ 25.0 and 22.5 g a.i ha-1 on plant height at harvest, number of tillers at 40 and 60 DAT and dry matter production at harvest. All the weed control treatments significantly improved the yield attributes viz., number of productive tillers m-2, grain weight panicle-1 and significantly lowered the sterility percentage as compared to weedy check. Penoxsulam @ 22.5 g a.i ha-1(T3) registered highest grain yield (5404 kg ha-1), net income (Rs 49065 /- ha-1) and B:C ratio (1.67) which was on par with other doses of penoxsulam(T4 , T2 and T1) as well as bispyribac sodium @ 30.0 g a.i ha-1 (T5) and 2,4 - D sodium salt (T6). Even though hand weeding twice registered grain yield comparable to herbicide treatments, due to very high labour cost involved, net income and B:C ratio were significantly low for this treatment. The weedy check recorded significantly lower values for grain yield, net income and B:C ratio compared to herbicide treatments and the yield loss due to weeds in this treatment was 22.13 per cent. Enumeration of soil microbial population 6 days after herbicide spraying revealed that the herbicides caused an initial reduction in the population of bacteria; but, there was no significant variation in the population of fungi and actinomycets , compared to weedy check where the rhizosphere was undisturbed. Considering weed control efficiency, grain yield, net income and B:C ratio, the new generation herbicide penoxsulam @ 22.5 g a.i ha-1 at 10 DAT can be adjudged as the best treatment for weed management in transplanted rice.
Open Access
Relative efficiency of ameliorants on rice productivity in lateritic soils of Kerala
(College of Horticulture, Vellanikkara, 2014) Anila, M A; KAU; John, P S
The correction of soil pH, reduction of toxic accumulation of native elements and supplementation of secondary nutrients may enhance the growth and productivity of rice grown in lateritic lowlands. A field study was conducted during January to May, 2013 at the rice field of College of Horticulture, Vellanikkara to evaluate the response of soil ameliorants on growth and yield of rice. The experimental design was RBD with 3 replications.Transplanted Jyothi was grown at 15 cm x 10 cm spacing in 5.0 m x 4.0 m plots. The soil was having an initial pH of 5.3. The treatments were amelioration of soil with different amendments such as CaO, dolomite, and ‘Mangalasetright’, which is a commercial product. The ameliorants were applied with or without fertilizer. The package of practices recommendation for low land rice, an absolute control treatment and fertilizer only treatment were also included for effective comparison. Nitrogen and potassium were applied in three equal split doses, first as basal dressing, second at tillering stage and the third at panicle initiation stage. The full dose of phosphorus was applied as basal dressing. CaO @ 377 kg ha -1 together with FYM and NPK, and ‘Mangalasetright’ @ 375 to 774 kg ha -1 constantly maintained a pH of more than 6, which is considered good for rice.Soil amelioration significantly increased the growth characters of rice such as height and tiller count in the presence or absence of fertilizers.Higher doses of ‘Mangalasetright’ resulted in significantly higher LAI than its lower doses.Application of CaO @ 377 kg ha -1 or ‘Mangalasetright’ @ 500 to 774 kg ha-1 together with fertilizer application also resulted in significantly higher improvement in root weight, root spread and leaf chlorophyll content.The leaf chlorophyll content was improved due to the combined effect of soil amelioration, organic manure addition and fertilizer application.The treatment which received the recommended POP for rice cultivation resulted in the constant improvement in rice dry matter production at all the growth stages, which was significantly highest.‘Mangalasetright’ at all the doses and CaO @ 377 kg ha -1 with fertilizer application have produced similar dry matter at 60 DAT and harvest than non application of ameliorants.Ameliorants other than dolomite created a favorable soil environment with an optimum pH and nutrient content which resulted in greater nutrient uptake by crop and consequent development of chlorophyll, enhanced photosynthesis and ultimately higher dry matter production. Amelioration improved all the yield attributes and consequently the yield. Among different ameliorants ‘Mangalasetright performed better than CaO and the lowest effect was observed for dolomite.The highest dose of ‘Mangalasetright’ and the treatment which received POP recommendation resulted in the highest and similar yield of 6.7 t ha-1. The superiority of ‘Mangalasetright’ even in the absence of organic manure addition is attributed to its Mg and S contents. The enhanced growth and yield characters of rice observed in the ameliorated treatments are due to the favorable nutritional rhizosphere environment in the soil and consequent nutrient availability and uptake. While CaO did the ameliorative function ‘Mangalasetright’ did both soil amelioration and secondary nutrient supplementation.
Open Access
Liquid formulations for production of organic oriental pickling melon (Cucumis melo var. conomon L.)
(College of Horticulture, Vellanikkara, 2014) Vemaraju, A; KAU; Usha, K
The study on “Liquid formulations for production of organic oriental pickling melon (Cucumis melo var. conomon L.)” was carried out in College of Horticulture, Kerala Agricultural University, Vellanikkara, Thrissur during 2013- 2014. There were two experiments viz. Effect of seed treatment with liquid formulations on germination and seedling vigour in oriental pickling melon and Evaluation of liquid organic manures on growth and yield of oriental pickling melon. The seeds treated with liquid organic manures showed better results in all observations such as germination percentage, length of radicle, length of plumule, dry weight, fresh weight and vigour index. The treatments receiving Panchagavyam+ Pseudomonas, Beejamrutham+ Pseudomonas, Panchagavyam and cow dung slurry were superior in early germination and seedling growth. The second experiment consisted of 11 treatments including different combinations of organic manures and supplements and package of practices recommendation by KAU. Saubhagya variety of oriental pickling melon was used for the study. The organic manures viz. poultry manure, coir pith compost, ground nut cake, neem cake and liquid organic manures viz. Jeevamrutham, Panchagavyam, Fish amino acid, Green leaf extract and Liquid extract of composite organic manures were the sources of nutrients. All the treatments except T were given basal and top dressing applicaton of organic manures as per the Package of practices recommendations (Adhoc) for organic farming : Crops. Seeds except in T 9 were treated with (Panchagavyam+ Pseudomonas) and have shown early germination and seedling vigour. Growth parameters like length of vine, number of leaves, dry matter production were significantly influenced by the treatments. The treatment receiving Fish amino acid recorded the highest length of vine (114.16cm) and number of leaves (37.66). Early flowering and harvesting could be achieved in Fish amino acid (22.66 9 and 50.66 DAS respectively) treated plots. Jeevamrutham treated plants had the highest dry matter production of 96.4g. Yield and yield attributes like number of fruits per plant, mean fruit weight, volume of fruit and yield per ha were also significantly influenced by the application of different liquid organic formulations. Highest number of fruits per plant (3.83) and weight of fruits (2.5 kg/plant), volume of fruit (770 cm 3 ) and yield per ha (30.33 t/ha) were observed in Jeevamrutham and Panchagavyam treated plots. With regard to the soil microbial count at different intervals of crop growth, the treatment receiving liquid extract of composite organic manure resulted in highest fungal population meanwhile Jeevamrutham had the highest bacterial and actinomycetes population . All the micro organisms were minimum in the treatments receiving Package of Practices recommendations of KAU. With regard to microbial count in liquid formulations the highest fungal and bacterial count was recorded in Panchagavyam followed by Jeevamrutham. NPK content was more in liquid extract of composite organic manure followed by fish amino acid. Kendall's test by ranks of the acceptability score revealed that there was significant variation among the treatments in the quality attributes of fruits. The highest score for appearance, texture, taste and colour was noticed in the treatment receiving Jeevamrutham followed by Panchagavyam and Fish amino acid. The overall acceptability was also more for the fruits from the organically treated plots. The treatment receiving Jeevamrutham was found to be significantly superior to other treatments in getting higher gross income, net return and B: C ratio followed by Green leaf extract and Panchagavyam.
Open Access
Weed management in ash gourd (Benincasa hispida (Thunb.) Cogn.)
(College of Horticulture, Vellanikkara, 2014) Sajeera, C Chathoth; KAU; Prameela, P
A field experiment on “Weed management in ash gourd” [Benincasa hispida (Thunb.) Cogn.] was conducted during July to November 2013 at Krishi Vigyan Kendra farm at KAU campus, Thrissur using the variety KAU local. The main objectives of the study were to compare the efficacy of cultural, physical and chemical methods of weed control and their combinations to arrive at an integrated weed management practice in ash gourd and to work out the economics of various weed management practices. The experiment was laid out in a Randomised Block Design with three replications. The treatments included pre- emergence application of oxyfluorfen @ 0.2 kg/ha, pre emergence application of pendimethalin @ 1.5 kg/ha, pre emergence application of oxyfluorfen @ 0.2 kg/ha followed by post emergence directed application of glyphosate @ 0.8 kg/ha, pre emergence application of pendimethalin @1.5 kg/ha followed by post emergence directed application of glyphosate @ 0.8 kg/ha, mulching with coconut fronds, mulching with polythene sheet, weeding using tiller, manual weeding by hoeing and no weeding. Major weeds found in experimental field were dicots which comprised of Alternanthera betzikiana, Borreria hispida, Celosia argentia etc. Pennisetum pedicellatum was the dominant grass species followed by Brachiaria sp. Plastic mulching of the field resulted in almost cent percent weed control efficiency. The lowest weed dry weight and highest nutrient uptake was recorded in plastic mulched plot which was statistically superior to all other treatments at all stages of observation. N, P and K uptake by weeds was higher in unweeded control and lower in plastic mulched, and the uptake increased from 30 DAS to harvest stage. The plant growth parameters like branches/vine and leaves/vine were significantly high in plastic mulched plots followed by hand weeded plot. The highest fruit yield (22,680 kg/ha) and seed yield (212 kg/ha) was recorded in plastic mulched plots which was statistically superior to all other treatments. Manual weeding was the next best practice and resulted in 16.54 t/ha fruit yield and 144.12 kg/ha of seed yield. Weed competition resulted in 91.5 per cent reduction in crop yield. Though total cost of cultivation was the highest for plastic mulching, it resulted in the highest net return and B:C ratio (2.73). Coconut frond mulching cannot be recommended as a weed control measure as it was found ineffective in suppressing weed growth and no net profit could be obtained. Application of pre-emergence herbicide alone could not take care of weed problem and hence can be recommended only for weed control during a short span of 30 days. The two pre-emergence herbicides tried viz; oxyfluorfen and pendimethalin had similar performance. Even a follow up spray of post emergence herbicide was found not sufficient to enhance the yield level. However this can be integrated with other weed control methods like manual weeding or mechanical weeding. It is concluded that plastic mulching is the best method for weed control in ash gourd in areas where weed problem is very severe.

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