IRRIGATION 



IRKKiATION 



835 



_-joints. The first tile wbere the water is introduced is 

 laid at an angle, one end resting on the edge of the 

 hench side. This leaves a wide opening at the first 

 ioint, which is closed with cement. A better plan is to 

 use a carved sewer-pipe for the inlet, but this is not 

 always available. The picture (Fig. 1182) shows hew 

 tlie tile is laid on the bench bottom, being a view ot a 

 side bench in a carnation house. 



Toll )\\ ing Goff's su.,g(sti n in tli use of I ri 1\ til s 



1183. Sub-irrigation with two tiers ol tile. 



liave been used over the entire bench bottom with good 

 results, and it seems probable that this will be found 

 to be the best form of construction, as it appears 

 more certainly to insure an even distribution of water. 

 The method of construction is the same as above de- 

 scribed, for the two plans differ only in the number 

 of tiles employed to distribute the water. Wheu the 

 lienoh bottom is covered with tile, placed near enough 

 together so that the soil will not fall between, it will be 

 readily seen that water introduced at any point will flow 

 to all parts of the bed lu and around the tile. It needs 

 simply to be brought up to such a level that it will reach 

 the soil, when capillary attraction will complete the dis- 

 tribution. Fig. I18:i shows a bench in a tomato house 

 ronstructed after this plan. AA are the inlets; B the 

 irrigating tile, from which the soil has been removed; 

 (' is the tile bench bottom, covered with cement. The 

 same size of tile, viz., 2%- or 3-inch, is used both above 

 •md helow. D is the cement side, which has been broken 

 away to show the method of construction. The outer 

 bo.ard has been removed also. 



The cost of construction need not be discussed here, 

 except to state that the only items extra, more than are 

 required in any well-constructed greenhouse, are the 

 cement bottom" and the tile in which the water is dis- 

 triljuted. 



A plan has been devised for applying water to small 

 plants in flats which may properly be mentioned under 

 this head. The flats are shallow boxes with slatteil bot- 

 toms. When the plants require water, the flats are 

 placed in a shallow vat of water aud allowed to remain 

 until the surface of the soil appears to be damp, or even 

 wet. 



A watering in this manner is far more efficient than 

 by the ordinary method. Taken in connection with sub- 

 irrigation in the benches, a crop of lettuce can be 

 brought to marketable size nearly two weeks earlier 

 than when surface watering is practiced. Anythmg like 

 a full discussion of results of experiments in watermg 

 plants in the greenhouse by sub-irrigation would be too 

 voluminous for an article in this connection. A brief 

 review of the results obtained at some of the stations, 

 together with a short discussion of some general prin- 

 ciples, will serve the purpose intended. The increase in 

 weight of lettuce from sub-irrigated plats over those 

 watered in the ordinary manner has been reported by 

 Rane, of West Virginia, as 25 per cent and by Goff and 

 Cranefield as 26 per cent. At the Ohio Station the 

 range has been from 2.5 to 100 per cent. In the hatter 

 case the result was obtained by commencing with the 

 plants as soon as taken from the seed-bed, and carrying 



the two lots through to the termination of the experi- 

 ment, one by watering altogether on the surface of the 

 soil, the other by sub-irrigation. Each of the experi- 

 menters speaks of a gain in earliness of several days 

 by sub-irrigation. Rane secured similar results with 

 long-rooted radishes by this method of watering, but 

 not with the turnip-rooted sorts, while i\lunsou, of 

 llaine, doubled the crop by watering below. Better re- 

 sults have usually been secured at the t^hio Station with 

 the turnip-rooted than with the long varieties, hut in 

 all cases there has been a gain in favor of sub-irriga- 

 tion, varying from 50 to 100 x^er cent. Rane found that 

 sub-irrigation increased the yield of tomatoes, but the 

 gain was not large. Essentially the same results have 

 been .secured in Ohi(j. The tonuito crop has not been 

 greatly influenced by the manner in which the water 

 was applied, and the same is true of beets, while sub- 

 irrigated cucumbers and parsley have shown a decided 

 gain over surface- watered. Carnations, roses, chrysan- 

 themums, sweet peas, violets and smilax have been un- 

 der experiment by the two methods of watering, aud 

 while no such nutrked results have been secured as with 

 letttice and radishes, the sub-irrigated plots have shown 

 stiperiorify r)vcr tliose watered in the ordinary manner, 

 in nearly all cases. AVitb carnations tlie improvement 

 has been mainly in length and stiffness of sti'm. 



Aside from the increase of crop secured by sub-irri- 

 gation, there are other considerations which may be 

 urgeil in its favor, andthcse are embodied in the follow- 

 ing general pirr)positions ; 



(1} ]Valerin(/ by ^tib-irrignf tnii hi tin' fifk-oiliouat' 

 ^aveti labor. The amotint of labor saved depends 

 mostly on tht completeness of the arrangements lor 

 watering, but there is a saving in the number of appli- 

 cations as well. It is possible to reduce the time em- 

 ployed in watering a house, or series of houses, to one- 

 flftii the time usually required. 



(2) Wuterimi by snb-irriijation assiirrs an abinithnd 

 and uniform .'iapplif of water to alt parti< of tin- ln-il. 

 Perfect constrtiction ot the benches is assumed in this 

 case, but with such construction watering becomes al- 

 most automatic, the only care necessary being to look 

 after such portions of the beds as may, by position, be 

 subject to unusual conditions of air or sunlight. 



(;'i) Where sub-irrigation is practiced in the green- 

 house, the surface of the soil does not become cominicfed, 

 but retains its original loose, friable condition. It is 

 true that where frequent syringing is practiced the sur- 

 face of the soil becomes more or less hardened, but not 

 to the e.xtent that occurs in surface-watering, and the 

 condition is easily reniedied, whereas in the other case 

 it is not. It follows that a heavier soil nuiy be used for 

 sub-irrigation than with surface-watering. 



Still other considerations might be urged in favor of 

 this method of watering, but many of them w(mld apply 

 to special cases only. Regarding the effect of the 

 method upon insects and diseases, but little can be 

 said. Lettuce rot is less preyalcnt upon sub-irrigated 

 plots than upon those which are surface-watered, but in 

 extreme cases plants succumb to the disease, whichever 

 method of watering is practiced. Munson found that 

 railishes suffered more from the attacks of millipedes 

 upon sub-irrigated plots than upon plots watered in the 

 usual manner. Nematodes work upon the roots of 

 roses, whichever way the plants are watered. The man- 

 ner of watering has no apparent effect upon the red 

 spider. Even in houses watered wholly by sub-irriga- 

 tion this pest is no worse than in houses in which the wa- 

 ter is applied to the surface of the soil. It may be said, 

 however, that nearly all classes of plants are more easily 

 kept in a healthy growing condition, and are thus better 

 able to resist enemies of all sorts, when sub-irrigated 

 than wheu supplied with water in the ordinary way. 



This methorl of applying water to plants in green- 

 house benches has now been .stiftlciently tested to de- 

 termine its value. All that now remains is to devise 

 ways and means to utilize what is known concerning it. 

 The adaptation to suit particular cases must be made by 

 individuals, but this will he far easier in the future 

 than in the past, because better methods of construction 

 prevail th.an formerly. The success of sub-irrigatioii in 

 the greenhouse is now simply a question of mechanics. 



W. .1. Green. 



