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TEXTBOOK OF BOTANY 



Table 10. Estimates of the Water Losses by Transpiration from Crops and 

 Plant Communities Growing Under a Variety of Conditions 



- ^ 



j Amount of Water Loss 

 [ per Acre 



Kind of Plant i ; 



in Gallons 



in x\cre- 

 inches 



Corn in eastern Kansas, 6,000 plants per acre, 100 325,000 



days 

 Corn in central Illinois, 10,000 plants per acre, 100 400,000 



days 

 Young apple orchard in central New York, 400 trees 240,000 



per acre, 188 days 

 An acre of irrigated date palms in a southern Cali- 2,. 500, 000 



fornia desert, 400 trees per acre, per year 

 An acre of 12-ft. columnar cacti in a southern Arizona 275 



desert, 400 plants per acre, per year 



11 

 15 



9 

 90 



0.01 



spring of the year than land which has remained barren since the previ- 

 ous season. It may therefore be plowed earlier. In dry farming the pro- 

 cedure is to cultivate the fields during the seasons in which no crops are 

 planted to prevent the growth of weeds and the loss of water through 

 them from the deeper layers of soil. 



Crop yields. Intimately associated with the effects of transpiration are 

 the yields of grain and other cultivated crop plants. The effects of exces- 

 sive transpiration probably result in greater reductions in the yield of 

 crop plants than all other factors combined, including diseases and 

 insects. 



In dry regions where irrigation is practiced the yield of grain is greatly 

 influenced by the amount of water added to the soil. Following are 

 figures for corn ( Utah Experiment Station ) : 



