384 GARDEN FARMING 



depth is not decreased. As the plants increase in size, the shovels 

 next to the row are raised so that the roots of the plants will not be 

 disturbed or injured. Sometimes two cultivations will suffice, but 

 the ordinary practice is to cultivate three times. At each cultiva- 

 tion a little additional soil is thrown toward the plants. 



The opening of the furrows for irrigation can be very success- 

 fully done with narrow, double-moldboard plows attached to a two- 

 horse cultivator so that one plow follows through the middle of 

 each row. These are so arranged that they make a deep, narrow 

 channel for the water, the depth being practically that to which the 

 cultivation has been carried, a furrow of from six to eight inches. 



Irrigation. After the furrows have been opened, a canvas dam 

 is thrown across the lateral which supplies the water, and the water 

 is turned into every other row. The head of water used depends 

 upon the contour of the land and the length of the row. If the rows 

 are long, with a slight grade, a larger head of water is used than 

 for short rows with a steep grade. Short rows with a steep grade 

 will get too little water if a large flow is used. The idea of irriga- 

 tion should be to wet the soil below the line of tuber formation and 

 to allow the water to rise by capillarity through the ridge upon 

 which the potatoes are growing. It is not considered the best prac- 

 tice to use enough water to saturate the soil ; only so much should be 

 used as will rise slowly by capillarity to meet the needs of the plants. 



The successive irrigations should be carried on in alternate rows ; 

 that is, the second irrigation should be in the rows not included by 

 the first, and the third irrigation should be in the rows used the first 

 time. Cultivation should follow irrigation as soon as the condition 

 of the soil will permit. Ordinarily it is not necessary to irrigate to 

 put the land in order for planting or to cause the tubers to germi- 

 nate. The first irrigation, under normal conditions, is given after 

 the plants are several inches high, but no set rule can be made. 

 The rainfall, the condition of the land, the temperature of the air, 

 and the intensity of the wind during the spring months should be 

 taken into consideration in determining the time for the first irri- 

 gation. In some seasons it will be necessary to irrigate early and 

 to repeat the irrigations at frequent intervals, while at other times 

 it may not be necessary to irrigate until the plants are about to 

 come into bloom. One of the common errors is to attempt to make 



