A decision support system for selection of tractor–implement system used on Indian farms C.R. Mehta * , Karan Singh, M.M. Selvan Central Institute of Agricultural Engineering, Nabi Bagh, Berasia Road, Bhopal 462 038, India Received 19 November 2009; received in revised form 25 February 2010; accepted 14 May 2010 Available online 11 June 2010 Abstract The selection of tractor and its matching implements has now become very difficult in India because of availability of variety of tractor models ranging from 10 to 45 kW. To overcome the problem of matching of tractor–implement system, an expert system modelling approach leading to decision support system (DSS) was adopted to make the step wise decision. The application of DSS was demon- strated in the paper to select either an implement to match the tractor or to select a tractor to match the implement under different soil and operating conditions. The DSS leading to computer software developed in Visual Basice programming provided the intuitive user interfaces by linking databases such as specifications of tractors and implements, tractor performance data, soil and operating condi- tions, to support the decision on selection of tractor–implement system. The programme calculates working width of implement based on input data for the most critical field operation and helps in selection of a suitable implement having width nearer to the calculated value among the commercially available implements. The software calculates the required drawbar power of the tractor based on draft and working speed of the selected implement. Finally, the PTO power requirement of a tractor is calculated by the software. Based on calculated PTO power, the software suggests available makes and models of tractor/machinery from the compiled data bank. The devel- oped DSS was tested with a case study to demonstrate the flexibility of the software. The DSS can be used effectively in selection of a tractor or an implement of particular size from various makes and models of commercially available tractors and implements. Ó 2010 ISTVS. Published by Elsevier Ltd. All rights reserved. Keywords: Decision support system; Tractor; Matching implements; Drawbar power; PTO power 1. Introduction Indian agriculture is characterized by small fragmented land holdings, hill agriculture and shifting cultivation. Twenty-two percent of semi-medium (2–4 ha), medium (4–10 ha) and large (more than 10 ha) farm holders, own 111.79 Mha (67.54%) of the total cultivable area of 165.51 Mha. The average size of farm holding is 1.55 ha which is further divided into 2–3 parcels. About 78% of the farm holders have less than 2 ha of land with poor resources especially in rainfed regions. However, 22% farm holders have an average holding of about 5 ha and are eco- nomically sound to invest in farm machinery. The growth in tractor production and sales in India has increased con- siderably during the last six decades. As a result, today around 300,000 tractors are sold annually. The average availability of tractors in the country is one tractor per 64 ha and the most popular size of tractor is in the range of 23–30 kW. Besides being used for ploughing and har- rowing operations, Indian agriculture uses tractors for har- vesting, threshing and transportation of agricultural and agro-industrial commodities. Unfortunately, due to varia- tion in soil conditions, operating practice, etc., most of the Indian tractors are operated in part-load conditions. Probably, a fallacy exists among the operators and tractor owners that operating the tractor on full load may lead to early deterioration of tractor performance. This factor also contributes to the under loading of tractors. Zoz [1] described a methodology for predicting tractor field performance based on drawbar performance for 4 WD tractor. Gould et al. [2] explained that the matching 0022-4898/$36.00 Ó 2010 ISTVS. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jterra.2010.05.002 * Corresponding author. Tel.: +91 755 2521124; fax: +91 755 2734016. E-mail address: crmehta@ciae.res.in (C.R. Mehta). www.elsevier.com/locate/jterra Available online at www.sciencedirect.com Journal of Terramechanics 48 (2011) 65–73 Journal of Terramechanics