IRRIGATION OF FIKI.D CROPS. 235 



and cease to grow, water becomes a necessity at no 

 matter what season, unless the crop has already or 

 nearly matured. 



If the spring has been cold and very backward, and 

 the subsoil is still lacking in warmth, it will be found 

 fatal to the potato plant to apply water, even if the soil is 

 very dry. It has been found that soils that are heavily 

 manured will take water at an earlier date in the spring 

 without injury to the plant than will poor, thin soils; 

 also by reason of the undecayed manure applied, it is 

 necessary to use water sooner than on unmanured soil. 

 One good watering will often mature a crop of pota- 

 toes, but if the growth of vines is heavy and shades 

 the ground well, two, or even three, waterings will in- 

 crease the yield, and can in no ordinary case injure 

 it. Each application of water should be followed im- 

 mediately with thorough cultivation until the vines are 

 too large or the tubers too near grown to permit of it. 

 Nothing is so damaging to a growing crop as to leave 

 the furrow or gutter in which the water has run to 

 bake and dry in the sun. Even when the advanced 

 growth of the vines and tubers will not permit it near 

 the base of the hill, cultivation may still continue with 

 profit as long as the furrow is in sight in the middle 

 of the row. 



In watering, it is best not to try to run water 

 through too long rows. As a rule it is best not to have 

 the rows over 40 rods in length. If the ground is very 

 steep, of course, the water will run quickly through, 

 but it will have to run longer than in a row with less 

 fall, to give it time to soak in ; and if the rows are too 

 long, by the time the water is through and the lower 



