Healthy Host and Its Requirements 67 



A careful study of Table 9 shows that excessive 

 watering results in a decrease of yield. Widtsoe and 

 Merrill in their work on sugar beets found that when 

 30 acre-inches of water is spread over one acre 30 

 inches deep, the yield was 20.82 tons. When this 

 same amount of water was spread over two acres 

 and for a depth of fifteen inches, the yield increased 

 to 38.90 tons per acre. Finally when the 30 acre- 

 inches of water were spread over six acres and five 

 inches deep, the yield increased to 82.68 tons per 

 acre. Every trucker should study the water require- 

 ments of the crops under his conditions of soil and 

 climate. To obtain the best results from irrigation 

 we must be familiar with the root system of each 

 particular crop and the depth to which it normally 

 penetrates the ground. 



Methods of Irrigation. There are two methods of 

 watering recommended. Each trucker can determine 

 for himself which of the two will give him the best 

 results under his particular conditions. 



(a) Subirrigation. As this implies, the water is 

 applied underground and through perforated pipes. 

 The conditions necessary for subirrigation are a clay 

 subsoil or a hardpan capable of retaining the irriga- 

 tion water. The topsoil must be of a sandy loam, 

 neither too loose nor too compact. The land must 

 be of a nature to admit of perfect drainage, having 

 a fall of one inch to each one hundred feet. The land 

 must also be level without raised places. Where 

 these conditions cannot be fulfilled, subirrigation 

 will prove a failure. The crops that are best bene- 



