PRACTICAL IRRIGATION IN HUMID AREAS 



METHODS EMPLOYED AND RESULTS OBTAINED 

 FROM THE APPLICATION OF WATER TO CROPS 

 IN REGIONS OF CONSIDERABLE RAINFALL. 



BY 



BRISTOW ADAMS. 



PART II. 



THE first part, published in the June 

 number of FORESTRY AND IRRI- 

 GATION, described irrigation for truck 

 gardens in the New England and Mid- 

 dle Atlantic States. This, the conclud- 

 ing part, takes up the question of 

 irrigation in the southern and western 

 parts of the humid area of the United 

 States, and gives the general conclusions 

 arrived at from the examples presented 

 in both papers. 



Florida- It must not be supposed 

 that the Atlantic seaboard states be- 

 tween Maine and the Florida peninsula, 

 outside of the two previously enumera- 

 ted, do not make use of irrigation, but in 

 general it may be stated that these three, 

 of the extreme Eastern States, have put 

 in the most expensive plants, and ones 

 involving greater outlays of time and 

 ingenuity, as well as money. Maine, 

 Connecticut, and Rhode Island, of the 

 New England group, have small areas 

 in irrigated crops, the water in the first- 

 named state being pumped from wells, 

 while in the latter states the water is 

 diverted from streams along bottom 

 lands at no other cost than the ditching. 

 New York and Pennsylvania of the 

 Middle Atlantic States, and the two 

 Carolinas, Georgia, and Alabama to the 

 south, make use of irrigation in some 

 degree, but as in the case of Connecti- 

 cut, only where every convenience is 

 afforded for direct application of water 

 from wells or streams without expen- 

 sive plants. In most cases the increased 

 value of the crop for one year will more 

 than pay the entire cost of installation 

 of irrigation service. 



When we come to Florida, however, 

 the irrigation question becomes broader, 

 more complicated, and more important 



in the state's agricultural development. 

 Conditions of soil and water supply 

 make possible in some localities a system 

 of sub-irrigation, easily installed, ex- 

 tremely effective, and simply operated. 

 While Florida has an abundance of rain- 

 fall, it is subject to severe drouths, es- 

 pecially during the growing period, from 

 February to June, when produce for 

 northern markets should make its best 

 growth. Underlying the whole state is 

 a high-water table, from which an un- 

 limited supply of water can be drawn 

 at all times. In many localities the soil 

 is sandy to the depth of about 4 feet, 

 under which sand there is an impervious 

 bed of clay or hard-pan. Beneath this 

 hard-pan, at varying distances of from 

 10 to 60 feet, abundant water can be 

 had with a strong surface flow. This 

 is piped from the well to the upper side 

 of the tract to be irrigated, where it is 

 conducted into a long pipe, having at 

 intervals downward extending valved 

 pipes which discharge into terra-cotta 

 pipes, each having an elbow turned to- 

 ward the piece of ground to be irrigated. 

 From these elbows, which are just above 

 the hard-pan, there extend into the field, 

 in the direction of the dip or inclina- 

 tion of the ground, lines of unglazed 

 tile, with a cross-section of the shape 

 of a horseshoe, open-side down toward 

 the hard-pan. When water is needed 

 the valves or cocks at the upper end of 

 the field are opened and the ends of the 

 tile drains at the lower end of the field, 

 where they discharge into a drain or 

 open ditch, are closed. The water from 

 the loose joints and open bottoms of the 

 tiles is taken up through the soil. When 

 the ground is sufficiently wet the water 

 is turned off at the supply pipe, the ends 



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