Scientific Agriculture. 



142 



[August, 1911, 



of soil from which there is no natural 

 outlet and accumulates there causing 

 that area to become saline. 



In all saline land in addition to these 

 harmful salts, there are present certain 

 other substances which form the food 

 of plants, and in fact for this reason 

 alkaline lands are generally exceedingly 

 fertile when once the obnoxious salts 

 are removed from them,and consequently 

 a considerable amount of attention is 

 being paid to their reclamation in many 

 parts of the world. 



From the foregoing it is evident that 

 the appearance of salinity is largely due 

 to deficiencies in drainage, and the most 

 successful methods adopted for the 

 reclamation of saline lands are those 

 which aim at improving the drainage of 

 such land. Many methods have been 

 suggested and em ployed for the allevia- 

 tion of the condition of saline lands, and 

 of these the most successful will be 

 described. 



A method often employed in previous 

 years consists essentially in covering 

 the saline land with a layer of fertile 

 soil. This is brought about either by 

 flooding the land with muddy water 

 and allowing the latter to drain off, 

 leaving the suspended matter behind, or 

 by carting soil on to the area so as to 

 cover it to a moderate depth. No doubt 

 with a certain expenditure it is possible 

 to obtain crops by this method, but the 

 causes which produced the salinity in 

 the first instance still remain in oper- 

 ation, and sooner or later the harmful 

 salts are concentrated in the new layer 

 of soil and the crops suffer. As an 

 efficient and permanent cure this method 

 cannot be recommended. 



A second method consists in dressing 

 the land with large quantities of gypsum 

 (sulphate of lime), and this substance by 

 reacting with the soda salts gives rise to 

 other substances of a less poisonous 

 character and permits crops to be 

 produced. At the same time it affects the 

 texture of the soil so as to improve the 

 drainage. The application of this subs 

 tance has undoubtedly been effective 

 under certain conditions, but it is scarce 

 in India, and therefore would probably 

 prove too expensive for use by the 

 ordinary cultivator. 



Probably the most effective way of 

 dealing with these soils is to well under- 

 drain the land and then subject them to 

 heavy irrigation with good water- The 

 cost of underdraining is, however, com- 

 paratively high, and on that account 

 would not commend itself to the ryot. 



A cheaper variation of this method is 

 to divide the saline area into com- 

 paratively large sections by means of 

 deep open drains, the earth so excavated 

 being utilized for the formation of bunds 

 around the sections. Each section is 

 then flooded with water to a moderate 

 depth, and the water then percolates 

 slowly through the soil to the drains 

 carrying with it the injurious salts, 

 Sometimes once flooding will clear the 

 land so as to enable crops to be grown, 

 but more often it is necessary to repeat 

 the operation several times whenever 

 sufficient water is available. Of course 

 such a method as this is inapplicable 

 whetever water is scarce as in many of 

 the dry lands of this Presidency, but it 

 can be carried out in many of the 

 irrigated areas, and often where an 

 efficient well supply is at hand. 



The ryots of the Kistna Delta reclaim 

 saline land by puddling in large 

 quantities of paddy straw and then 

 flooding with water. The straw in itself 

 assists drainage, and even after decom- 

 position has taken place the humus 

 produced has the same effect. 



THE ADVANTAGES OF DRAINAGE. 



By G. R. Hilson, 

 Deputy Director of Agriculture, 

 Northern Division. 



(From the Madras Agricultural 

 Calendar, 1911-12.) 

 Every cultivator knows that if crops 

 are to be grown successfully, one of the 

 most important points to be considered 

 is the question of water-supply. The 

 question of drainage is equally im- 

 portant. 



It may at first seem absurd that, after 

 having incurred expenses either in 

 digging a well or in acquiring the right 

 to irrigate his lands from a tank or a 

 canal, any one should go to the further 

 expense of constructing drains, merely 

 for the purpose of leading the water so 

 obtained, away from the fields again, 

 where it will be of no further use to 

 the crop. There are, however, several 

 advantages to be gained by good 

 drainage which only need to be pointed 

 out to be appreciated. 



Any one who has observed such crops 

 as cholam, cumbu, korra, etc.. will have 

 noticed that if during the earlier stages 

 of growth water is allowed to collect 

 and stand in the lowlying portions of 

 the fields, the plants in these places are 

 always pale, stunted and unhealthy 

 looking, and that at the time of harvest 



