Vol XIII. No. 311. 



TBE AGRICULTURAL NEWS. 



103 



AGRICULTURAL ENGINEERING. 



SUBSOILING IN SOUTHERN INDIA. 



The employment of dynamite for soil improve- 

 ment purposes is becoming more and more general. 

 The following is an account of an interesting demon- 

 stration carried out in Southern India and described 

 in the Planters Chronicle, of January -"U, 1914:— 



Thiee plots of Jacre each were treated. In the first 

 two plots a piece of coffee t-jVe years old was treated. The 

 surface soil was hard, wiih gravel. A pit dug at the bottom 

 of the plot showed a layer of boulders about 2 feet deep, 

 below this a layer of quartz, while at i feet the red clay 

 was reached. 



In another pit about half the way up, the red clay was 

 reached at 3 feet. A cutting further along shows the bed of 

 clay for 10 feet and it hr>d rot then reached the bottom. 

 During the drilling of the holes this clay was reached at 

 various points at varying depths, the shallowest being 

 about 1 foot. 



The third plot in another place was in a somewhat 

 typical heavy red clay. The coffee here was very bad. This 

 type of land occurs in patches all along these hills. The 

 shade grows, but the coffee will not. 



In plot 1 the charges were placed 10 feet x 10 feet 

 two rows full cartridges, three rows half cartridges. Depth 

 of hole 2 feet. In plot 2, the charges were placed 1-5 feet x 

 1.5 feet two rows half cartiiug« .iod three rows full cartridges. 

 Depth of hole 2 ftet. Li i-^' 3, the cartridges were placed 

 12 feet X 12 feet all full cartridges, and the holes 3 feet deep. 

 The explosive used was Nobel's Gelignite, slightly more 

 powerful and more expensive than the Farmer's dynamite 

 which is now being imported especially for this work. 



Before lighting the fuse, the end of the fuse was opened 

 to the powder and a small piece of Gelignite inserted, this 

 enabled the fuse to be fired by merely touching it with 

 a lighted cigarette. After the charges had all been 6red 

 Mr."Mc<^ieen pointed out that with the half cartridge at 2 

 feet depth the surface soil was not much displaced. This 

 was as it should be, the force of the explosion was all expended 

 in the soil. The lull cartridges at 2 feet deep displaced the 

 surface soil to some extent, showing a waste of force above 

 ground. The full cartridge at 3 feet deep appeared very 

 effective. The shock could be felt 30 and 40 yards away, 

 but the surface soil was not displaced. 



To demonstrate the fallacy that dynamite strikes down- 

 wards, whereas.it really takes the line of least resistance, 

 Mr. Mc<i>ueen placed a cartridge on the road and covered it 

 with a kerosene oil tin. The road was hardly marked but 

 the tin ha> not been seen again. A trial hole was also bored 

 in a road, 2 feet deep. A full cartridge inserted and fired. 

 The cracks could be traced on this hard surface for 3 feet 6 in. 



A tree stump was also blasted. Owing to coolies having 

 used the wood augurs as earth augurs at a previous demon- 

 stration it was impossible to bore into the taproot to 

 a sufficient depth. The tree was a dead gall nut, and very 

 hard. Holes were bored as nearly below the tap root as 

 could be guessed and the charge fired by electricity. One 

 side of the tree was torn out and a piece weighing over 1 cwt. 

 thrown clear over the coffee on to a road about 15 yards away. 



Later in the evening nine and a half cartridges were 

 placed on a block of ironstone measuring about 3 feet x 

 4 feet >. 6 feet, total 72 cubic feet. These were covered 

 with wet clay and the whole fired off together. The stone 

 was cracked from top to bottom and several transverse cracks 

 also made. 



STEAM PLOUGHING IN BOMBAY. 



A paper on the above subject, which appeared ia 

 Bulletin Xo. .54, Bombay Department of Agriculture, 

 is abstracted in the Experiinent Station Record as 

 fo!!o'.vs: — 



This bulletin deals with mechanical ploughing outfits as 

 regards their adoption in the Bombay Presidency. Detailed 

 descriptions and sketches are given of five general systems, 

 viz., (1) the direct traction system; (2) direct cable-drawa 

 implement.^ on the double engine system; (3) indirect cable- 

 drawn implements on the roundabout system with a traction 

 engine fitted with winding drams; (4) indirect cable-draws 

 implement.s but with a portable engine driving a separate 

 windlass; and (5) direct cable-drawn implements worked with 

 bullock geared windlasses. The various conditions of soil, 

 vegetation, and atmosphere in the Bombay Presidency are 

 described as favourable to the profitable application of 

 mechanical cultivation, particularly f'<-: the eradication of 

 hariali grass, for which it is necessary to turn up the soil to 

 a depth of at least 16 inches. A badly infested area of 

 14 acres was ploughed 14 to 16 inches aeep. The work was 

 started in January and finished in April, and by August the 

 crop was looking remarkably well and the hariali grass was 

 practically extinct. 



From various service tests and operations statements of 

 the advantages and disadvantages of each system are made 

 with estimates of the capital outlay, the annual working 

 expenses, and the cost per acre ploughed for each system. The 

 total capital outlay for an outfit of the tirsi class, consisting 

 of an 80 h.p. engine, balance plough, uuluL^tor, and harrow, 

 is estimated at 21,300 rupees (about §5,900 . and the annual 

 working expenses at 8,6.50 rupees. With this outfit plough- 

 ing by direct traction it is not possible to plough to a depth 

 of more thtn 8 or 9 inches in black cotton soil, but it is 

 estimated that with two shifts of men this engine will 

 plough 8 acres per day of fourteen hours to a depth of 

 8 inches at an average cost per acre of 8 rupees and .5 annas 

 (about .S2-60). 



The total capital outlay for an outfit of the second type, 

 consisting of two 80 h.p. engines, plough, cultivator, and 

 harrow, is estimated at 40,500 rupees, and the annual working 

 expenses at 15,12.5 rupees It is estimated that this outfit 

 with two shifts of men will plough in black cotton soil 8 acres 

 per day to a depth of from 16 to 18 inches at an average cost 

 per acre of 14 rupees and 8 annas. When ploughing at 

 a depth of 8 or 9 inches with this outfit the cost per acre is 

 estimated at 5 rupees and 13 annas (about .gLOO). 



For an outfit of the third type, consisting of one 80 h.p. 

 engine and other equipment, the total capital outlay is esti- 

 mated at 28,800 rupees, and the annual working expenses at 

 9,986 rupees. It is estimated that with two shift.s of men 

 this outfit will plough 6 acres per day to a depth of from 16 

 to 18 inches at an average cosl per acre of 14 rupees. 



The total cai'ital outlay for a small outfit of the fourth 

 type of the cheapest possible construction, consisting of one 

 18 h.p. engine and other equipment, is estimated at 12,150 

 rupees, and the annual expenses at 3,867 rupees. It is 

 estimated that with two shifts of men this outfit will plough 

 1 to U acres per day, to a depth of from 16 to 18 inches at 

 an average cost per acre of 28 rupees and 4 annas. 



For an outfit of the fifth type the total capital outlay is 

 estimated at 3,196 rupees and the annual working expenses 

 at 1,452 rupees. It is estimated that this outfit will plough 

 '-acre per day of black cotton soil to a depth of from 16 to 

 18 inches and can be worked 150 days in one year, ploughing 

 37| acres at an average of 39 rupees per acre. 



