TY - BOOK AU - Lekshmi Sekhar AU - George Thomas, C (Guide) TI - Weed management in elephant foot yam[amorphophallus paeoniifolius (dennst.)nicholson] U1 - 630 PY - 2017/// CY - Vellanikkara PB - Department of Agronomy, College of Horticulture KW - Agronomy N1 - MSc N2 - Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson) is a popular tropical tuber crop grown in Kerala because of high production potential and net returns. In Kerala, elephant foot yam is second in importance as a tuber crop after cassava and in 2015 - 16, it was grown in 7143 ha. In general, weed competition is an important constraint in the production of tuber crops owing to their initial slow growth. Elephant foot yam, being a widely spaced crop, takes 50 - 60 days or more to spread into full ground cover. Therefore, in the early growth stage of this crop, enough sunlight and space are available for weeds to flourish. Manual weeding is the most common method of weed control practiced in elephant foot yam, and two weedings, one at 45 days and the second at 75 days followed by earthing up, are recommended in Kerala. However, the high cost of manual weeding and non- availability of labour are major constraints in weed management, and so, farmers seek alternate methods of weed control. The present experiment entitled “Weed management in elephant foot yam [Amorphophallus paeoniifolius (Dennst.) Nicolson]” was conducted in the Department of Agronomy, College of Horticulture, Vellanikkara during March to December 2016 to study the effect of frequency of weeding and various weed management techniques on the growth and yield of elephant foot yam. Treatments included manual weeding (twice, thrice, and four times), weed management by herbicides, mulching with black polythene sheet, mulching with dry grasses, intercropping with cowpea, and unweeded control. Among various treatments, mulching with black polythene displayed superior biometric characters and yield. Mulching with black polythene showed the highest per plant leaf area of 83.11 dm2 and leaf area index of 1.02. The treatments with herbicides were next in order. All the plots receiving manual weeding were on parwith respect to leaf area and LAI. Irrespective of the stage of crop, mulching with black polythene produced higher plant dry weight throughout the crop period. The treatments, mulching with dry grasses and intercropping with cowpea were not effective in suppressing weeds to any marked level as shown by lesser crop dry weight throughout the growth period. Mulching with black polythene greatly influenced the height, diameter, and volume of corm followed by pre emergence application of oxyfluorfen and directed spray of glyphosate. Mulching with black polythene also positively influenced the fresh weight of corm, recording the highest fresh weight of 2.70 kg/ plant and corm yield of 35.77 Mg/ha, which was 63 per cent higher than unweeded control. Increase in frequency of manual weeding also caused significant effects on fr esh weight of corm and corm yield per hectare. Mulching with dry grasses, intercropping with cowpea, and pre emergence application of pendimethalin were not very effective in obtaining higher corm yields. Mulching with black polythene was the best option to manage weeds in elephant foot yam fields at all growth stages. In general, application of herbicides limits the weed dry weight greatly but pre emergence application of pendimethalin was not that effective compared to oxyfluorfen and glyphosate. Mulching with black polythene maintained the highest weed control efficiency at all the stages except at 165 DAP. However, mulching with black polythene gave consistent weed control efficiency upto 105 DAP after manual weeding four times, and at 165 DAP, it was the second best in controlling weeds. An increase in soil acidity and organic carbon content was observed after the harvest of crop. In general, mulching with black polythene recorded higher contents of all nutrients except N in soil. Mulching with black polythene resulted in higher nutrient contents in corms both at 90 DAP and harvest. Uptake of major nutrients was also higher in this treatment. Among manually weeded plots, weeding thrice and four times resulted in on par uptake of N and P at harvest. Directed spray of glyphosate and pre emergence application of oxyfluorfen resulted in higher nutrient uptake among the plots receiving herbicidal application. The highest benefit - cost ratio of 2.33 was recorded with mulching with black polythene. The B : C ratio of pre emergence application of oxyfluorfen and post emergence spray of glyphosate were 2.28 and 2.24 respectively. Manual weeding four times resulted in a B : C ratio of 2.02. From this experiment, it can be concluded that mulching with black polythene, pre emergence application of oxyfluorfen and post emergence application of glyphosate can be effectively utilized for weed management in elephant foot yam. UR - http://krishikosh.egranth.ac.in/handle/1/5810140422 ER -