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loam or even in light sandy soils. It is practiced to a considerable 

 extent in the light sandy soil of the truck area of the Atlantic Sea- 

 board, where the question of a few days in the time of ripening of the 

 crop is an important factor. 



IRRIGATION. 



If the climatic conditions are such that it is impossible, with the 

 most improved methods of ploughing, subsoiling, and subsequent culti- 

 vation, to maintain a sufficient amount of moisture in the soil for the 

 use of crops, it is then necessary to resort to irrigation or the artificial 

 application of water to the soil. It is not the purpose here to enter 

 into a discussion of the best methods of irrigation but simply to discuss 

 briefly the general principles of irrigation as practiced in maintaining 

 proper conditions in the soil. 



Our ideas of irrigation should not be confined to the arid regions. 

 To be sure, irrigation is much more important there than elsewhere, 

 for without artificial application of water, crops could not be produced 

 in many localities. In the humid portion of the Uniied States, even 

 in localities in Florida where they have from 60 to 70 inches of annual 

 rainfall, irrigation is used successfully as a means of insuring the 

 crop against drought due to the uneven distribution of the rainfall. It 

 has been pointed out in several publications of this division that where 

 the supply of water in different soils reaches a certain point, which 

 differs according to the texture of the soil, crop suffer for lack of it. 

 In the truck soils of the Atlantic Coast this minimum is approximately 

 4 per cent, while in the heavy limestone grass lands of Kentucky the 

 pasture begins to dry up when the soils contain as much as 15 per cent 

 of water. 



Under our present modes of cultivation the farmer can do little for 

 the crop during the time of actual drought. Ordinary cultivation is of 

 comparatively little benefit during a prolonged dry season. Its most 

 effective work is before the dry spell sets in. No matter what the 

 value of the crop, and no matter how much this value is concentrated 

 on small areas of land, there is practically but little to be done to 

 save the crop. Irrigation should be used as an insurance against the 

 loss of crops. A small pond fed by a wind mill would often save a 

 garden or a small area of a valuable crop from destruction or great 

 injury during a dry season. A small portable farm engine, which 

 would be available at other times for cutting feed, thrashing grain, 

 and other farm purposes, could be used to drive an irrigation pump 

 during the dry seasons. This would be particularly valuable for 

 tobacco, truck, and other crops which are grown under a very intensive 

 system of cultivation. 



The object of all cultivation, in its broadest aspect, is to maintain,, 

 under existing climatic conditions, a uniform and adequate supply of 

 water and air in soils, adapted to different classes of plants. This is the 

 object alike of ploughing, subsoiling, cultivation, underdrainage, and 

 irrigation ; they are all processes to be usod in maintaining suitable 

 moisture conditions for the growth of crops. 



