Design and development of a lime applicator attachment to tractor operated rotavator

Abstract

Lime application is used to reduce the acidity of the soil and to enhance plant root for easy absorption of nutrients for better yield. Usually lime is being applied manually for all crops. In addition to the non-uniformity in application, the manual application of lime causes health hazards and so labourers are reluctant to do this job, moreover it is a costly practice. Hence, a mechanical means of lime application is inevitable. To apply lime mechanically, an investigation was undertaken to design and develop a lime applicator attachment with tractor drawn rotavator, which simultaneously applying lime and till the soil. The unit was developed as a rear mounted attachment to four wheel tractor to having 45 to 65 hp attached with rotavator. The power output to the lime applicator attachment was taken from the rotavator shaft. This study deals with the basal dressing of lime for paddy at the rate of 350 kg ha -1 as per the recommendation of Kerala Agricultural University Package and practices recommendations, 2011. The major components of the lime applicator attachment was hopper, metering mechanism, lime discharge chute, agitator and sprockets and chain with box assembly. The trapezoidal hopper was made up of galvanized iron sheet folded in 54° having dimension of 1600 × 460 × 340 mm. Single shaft baffle type metering mechanism with drive taking from the rotavator was used to metering lime. The field performance evaluation of developed lime applicator was held in Instructional Farm, KCAET, Tavanur. During the field performance evaluation, the soil moisture content, bulk density and soil pH were found as 16.2 %, 1.73 g cm -3 and 5.6 respectively. The data taken during the field evaluation were statistically analyzed. Application rate of lime was increased with increase in engine rpm of tractor. It is because, when engine rpm increases rotavator speed also increases which in turn increased the rotational speed of metering mechanism and agitator.From the statistical analysis, a special range of rate of application of lime of 335 - 360 kg ha -1 with a critical difference of 15 kg ha -1 was obtained. A value near to the desired rate of application of lime of 350 kg ha -1 was resulted at 2000 rpm of tractor engine under L 1 gear with speed ratio of metering mechanism P 3. Similar results equivalent to desired rate of application of lime was achieved at 1800 and 2200 rpm with speed ratio of metering mechanism P 2 and P 3 . The corresponding forward speed obtained was 2.56 km h -1 with wheel slippage of 11.67 per cent. Fuel consumption was 3.7 l h -1 and 26 l ha -1 . For applying lime with proto type lime applicator in an area of 0.4 ha, a time of 1.2 hrs was taken. The actual field capacity, theoretical field capacity and field efficiency were calculated as 0.33 ha h -1 , 0.39 ha h -1 and 84 per cent respectively. Cost of operation of the proto type lime applicator as an attachment to tractor drawn rotavator was found as 567.15 Rs h -1 and 1718.63 Rs ha -1 and manual lime application followed by tractor ploughing was 627.12 Rs h -1 and 1985.21 Rs ha -1 . A cost saving of 59.97 Rs h -1 and 266.58 Rs ha -1 with proto type lime applicator over manual lime application followed by tractor ploughing was observed. Also, a time saving of 2 h ha -1 over the manual lime application followed by tractor ploughing was achieved with proto type lime applicator attachment.