Combine harvesting efficiency as affected by rice field size and other factors and its implication for adoption of combine contracting service

Abstract

Small combine harvesters have become popular in SE Asia recently, but small rice fields appear to limit its field operation and hence its wide adoption by smallholders. Combine harvesting efficiency, the area of paddy field harvested per unit time, was determined for 6 seasons in Central Lao PDR for over 400 fields varying in size and toposequence position, rice varieties grown, crop establishment methods and crop conditions particularly lodging at harvest. Combine harvesting efficiency was commonly about 3 ha/day in small fields of less than 1000 m 2 and increased with the increase in field size up to 5 ha/day in the size of about 2000-3000 m 2 , but not beyond this range. Lower efficiency was also found in wet season than dry season, and also crops established from broadcasting compared with transplanting and drill seeding, at least partly because broadcasted crops tended to lodge more often than crops established from other methods. Photoperiod sensitive, long duration varieties grown in lower field positions also tended to have lower combine efficiency. Using the data obtained in this work, net return of combine adoption to farmers was estimated for different combine charge fees and yield levels. Increasing combine harvesting efficiency by 50% with increased field size would increase the net income of combine harvesting contractors by around 50% at current charges, allowing them to reduce the combine harvesting fees they charge. This would aid the adoption of combine harvesting services.

Research strategies for mechanised production of rice in transition from subsistence to commercial agriculture: a case study from Khammouan in Lao PDR

“…Combine harvested crops do not require the additional threshing process as it is in-built in the combine harvester, and this again saves further time and cost. Economic analysis indicates large benefits to farmers adopting combine harvesting contracting service, particularly in areas with high labour cost (Bunna et al, 2018;Xangsayasane et al, 2019c). Their study also indicated that combine harvested grain yield was similar to hand harvested yield and grain harvesting loss was about 1.5% of the total yield, which was less than the total loss for manual harvested crops when the losses during threshing and handling of paddies was included.…”

“…In the province, 24 combines (Kubota DC70) are now available compared to 2 in 2015 (Table 1), and they are mostly operated by contractors. When the fees are based on 10-20% of the crop produced with a yield of 2.3-3.2t/ ha (Table 4), the charge is in the range of 69-190USD/ha (Xangsayasane et al, 2019c). While combine service fees have become cheaper in Laos including Khammouan from (Bunna et al, 2018).…”

“…This high combine charge appears to be related to limited competition because of only a small number of contractors available, low combine harvesting efficiency particularly due to small field size (Xangsayasane et al, 2019c), the short time period for payback of credit for purchase of combines, and the limited number of days per year that combine contractors can operate in Laos. The combine contracting saves time and the cost of labour where typically 30 people are employed to manually harvest 1 ha of land (Xangsayasane et al, 2019c). Combine harvested crops do not require the additional threshing process as it is in-built in the combine harvester, and this again saves further time and cost.…”

“…While these measures will help improve rice yield and as a result labour productivity to some extent, greater impact on the labour productivity may be achieved when the labour input is reduced greatly without reducing yield. Thus, mechanization is a key to improving labour productivity, reducing production cost and yet maintaining grain yield (Bunna et al, 2018;Xangsayasane et al, 2019c). Khamphoukeo (2014) described the extent of current mechanization practices in Laos, and mentioned that Viengkham Agricultural Machinery Centre that was developed in the 1980s as a result of the Government's recognition of the importance of agricultural mechanization could not be sustained.…”

“…Key rice mechanisation technologies for crop establishment, harvesting and grain drying have been trialled in these provinces, and major results published in the current Special Issue and elsewhere. Thus, mechanised operations have been compared with manual operations for seed drill (Sengxua et al, 2018;Xangsayasane et al, 2019a), transplanter (Xangsayasane et al, 2019a), combine harvester (Xangsayasane et al, 2019c;Xangsaysane et al, 2016) and flatbed dryer (Vongxayya et al, 2019;Xangsayasane et al, 2019b) in terms of grain yield, grain quality particularly head rice yield, and financial gain to farmers of adoption of contracting services for mechanised operations. This paper summarises the recent research achievements for mechanised rice production in this and other provinces in the country and suggests research strategies that would further enhance the mechanised rice production.…”