~ 997 ~ International Journal of Chemical Studies 2020; 8(5): 997-1002 P-ISSN: 2349–8528 E-ISSN: 2321–4902 www.chemijournal.com IJCS 2020; 8(5): 997-1002 © 2020 IJCS Received: 22-06-2020 Accepted: 24-08-2020 T Krishnakumar Scientist, Division of Crop Utilization, ICAR-CTCRI, Trivandrum, Kerala, Thiruvananthapuram, Kerala, India MS Sajeev Division of Crop Utilization, ICAR-Central Tuber Crops Research Institute (CTCRI), Sreekariyam, Thiruvananthapuram, Kerala, India G Suja Division of Crop Production, ICAR-Central Tuber Crops Research Institute (CTCRI), Sreekariyam, Thiruvananthapuram, Kerala, India Corresponding Author: T Krishnakumar Scientist, Division of Crop Utilization, ICAR-CTCRI, Trivandrum, Kerala, Thiruvananthapuram, Kerala, India Effect of planting methods and varieties on performance of modified TNAU cassava harvester T Krishnakumar, MS Sajeev and G Suja DOI: https://doi.org/10.22271/chemi.2020.v8.i5n.10427 Abstract Cassava is one of the most important tropical tuber crops that ensure food and nutritional security in the developing countries. In India, cassava is cultivated mainly in the southern states viz., Tamil Nadu, Kerala and Andhra Pradesh. Harvesting is one of the major difficult and labour intensive operations in cassava cultivation. In India, cassava is mostly harvested manually by hand. This study was attempted to evaluate the performance of tractor operated Tamil Nadu Agricultural University (TNAU) cassava harvester with two industrial varieties (H-165 and Mulluvadi) and two commercial planting system (Mound and Ridge) using six treatments in a randomized complete block design (RCBD). Based on the field performance trial, the shank length and width of digging blade were modified and then their dimensions were optimized for better performance. Among the selected treatments, it was found that a minimum damage of 4.12% was observed for H-165 variety under manual harvesting and a maximum damage of 9.05% for Mulluvadi variety in mound planting system under mechanized harvesting was noticed. The tuber spread length was highly correlated with the per centage damage (%) of cassava tubers. Thus, the tuber spread length is an important agronomical parameter to be considered while selecting the variety for mechanization of cassava harvesting. This study also confirmed that the ridge planting system is highly suitable for operating mechanized harvester as compared to mound planting system. Keywords: Cassava, industrial varieties, ridge planting, mound planting, harvesting, damage loss Introduction Cassava (Manihot esculenta Crantz) is one of the major tuber crops, locally called as tapioca and cultivated in tropical and subtropical regions of the world. It is the third largest source of carbohydrates after rice and wheat for people all over the world and the starch content of cassava tubers varies according to varieties (Krishnakumar et al. 2019) [7] . In India, it is cultivated about 0.20 million hectares with a total production of 8.13 million tonnes and a productivity of 22.3 metric tonnes per hectare (Krishnakumar et al. 2020) [8] . Tamil Nadu stands first in the production and processing of tapioca into starch and sago. In Kerala and North-Eastern States, tapioca is consumed directly by the people whereas in Tamil Nadu more than 80% production of tapioca tubers is being processed into sago and starch (Krishnakumar and Sajeev, 2017) [6] . The dried cassava tubers consist of about 80 to 90 per cent (%) carbohydrate, out of that starch which ranges from 78 to 90% on dry basis. It is also considered as a good source for minerals such as calcium, iron, magnesium and phosphorus and has higher calorific value compared to other tubers such as yam, potato and sweet potato. Native cassava starch is mainly used for production of sago, monosodium glutamate (MSG), glucose and bakery products, whereas modified cassava starch is used for textile, glue, paper, plywood and the pharmaceutical industries (Sheriff et al. 2005). The cultivation of cassava is currently facing a labour shortage, topographic constrains and non-availability of appropriate machineries for replacing labour. In cassava cultivation, labour requirement is invasive during planting, weeding, fertilization and earthing up besides harvesting. Harvesting is one of the major difficult and labour intensive operations in cassava cultivation. This is because cassava is highly perishable and prone to deteriorate after harvest within 48 hrs due to surface damage and post-harvest physiological deterioration (PPD). Thus enough moisture to be maintained at the time of harvest in order to reduce the damage of fresh cassava tubers. The cassava crop is ready for harvest after 10 to 12 months after planting.