Mechanization of Sweet Sorghum sowing operation

In sweet sorghum crop, the best sowingwindowwas limited 2 to 5 days depending on the moisture availability after monsoon arrival. Success of sweet sorghum farming depends on completion of sowing operation within this limited period. Otherwise the entire crop cycle will be affected by delayed sowing. The recommended plant to plant spacing was 20 cm and row to row spacing was 60 cm. However most of the farmers were not convinced for this spacing with preconceived apprehensions on yield, hence the sowingmachine setting was changed to 20 cm and 45 cm respectively.  In conventional practice, sowing operation was done by a country plow to open the furrow followed by two women labour to place the seed and fertilizer. This resulted in poor germination as there was no synchronization between the labours. To overcome this, improvedsowing implements suitable for the cluster were introduced to meet the timelinessand precision to complete the sowing in this short window period. The implements included in the trials were  4-row bullock drawn planter, 6-row and 9-row tractor drawn planters which were designed and developed by Central Research Institute for Dryland Agriculture and extensively popularized in dryland regions of India.  Specifications of 4-row and 9- row planters are given (Table 1).

Table 1: Specifications of the CRIDA planters

Specification	4-row Planter	6-row planter
Weight (kg)	120	240
Source of Power	Bullock	Tractor (35 hp)
Plant to Plant spacing (cm)	20	20
Row-row spacing(cm)	45	45
Row coverage	3	4
Field Coverage (ha/day)	3-3.5	7-8
Cost of operation (Rs/ha)	800	600

 Initially, to propagate the concept of mechanization in the backward and tribal areas of Medak district, a field demonstration cum training was arranged in farmer’s fields at Ibrahimbad thanda village to demonstrate working of the planter condition and to create awareness among the farmers in the cluster area. During field testing, the performance of 4-row bullock drawn and 6-row tractor drawn planters was found to be satisfactory. The farmers could not use the 9-row tractor-drawn planter since their land holdings are verysmall. Some of the modificationsregardingseed metering mechanism were done to planters to achieve 20 cm plant to plant spacing. Though the row to row distance of 60cm is recommended for sweet sorghum, the farmers could not adopt it because of preconceived perception in yield reduction with less plant population. Hence a demonstration was conducted with 45cm row to row spacing only.  As part of the training programme, farmers were also trained in repair and maintenance of sowing machines which helped them to understand the basic principles of the machinery. Poor response for bullock drawn planters was recorded as it covers lesser area in the limited sowing time available .The field evaluation of CRIDA 6- row planter was given in Table 2.  The crop grown with CRIDA planter (Fig.1) and conventional method (Fig.2) are shown below for visual comparison.

It is observed that mechanized sowing operation helped in time saving by 65 % under limited sowing window period. Though the bullock drawn planters were introduced, it was very difficult to popularize among the farming community. This intervention resulted in 15 % saving in seed cost, 30 %labour cost apart from yield increase by 15 % which can be contributed to  better usage of available moisture content and placement of seed and fertilizer at proper depth and spacing (Mayandeetal 2004).

Table 2:  Performance of CRIDA planter for sweet sorghum

Method of sowing	Average plant to plant spacing (cm)	Average row to row spacing (cm)	Biomass yield (t/ha)
Farmer’s practice(country plough)	10	40	20
CRIDA6-row planter	20	45	23

 

Effect of mechanized sowing on crop growth

As expected mechanized sowing improved the crop growth in terms of plant height and stem girth which normally influence the juice recovery.The observations on height and thickness of stalk for the consecutive three years are recorded to know the performance of seed drills on crop physical properties and results are given in Table3.

The stem diameter and height of mechanized sowing are more than the farmer’s practice which may be attributed to the proper placement of fertilizer and seed in proper place with the planter when compared with the farmer’s practice. The well spaced row sowing improved the yields considerably apart from making the stem more suitable for crushing.

 Table 3: Effect of sowing methods on Crop physical properties

Methods	Plant height at harvest(cm)(in 100 m x 100 m plot)	Stem diameter at harvest stage (mm)
Farmer’s practice	294	17.4
Mechanized sowing	315	21.2