November, 1908.] 



459 



Scientific Agriculture. 



sandy soil more. This, of course, is not 

 taking into consideration the rainfall. 

 Corn, requiring only a short period in 

 which to develop, would not require as 

 much water as sugar cane, for example. 



Mountain or upland rice would require 

 about the same as corn, but rice that 

 has to be flooded would require much 

 more, as the water would have to be 

 maintained at a depth of from 6 to 15 

 inches on the land, and this would have 

 to be changed a number of times during 

 the season. There is little loss by per- 

 colation on this kind of soil, however, as 

 most rice lands are compact. 



It requires much practice to know 

 just how much water to use in a humid 

 climate like that found in these Islands. 

 The best guide is the "condition" of the 

 soil, tor such crops as corn, sweet 

 potatoes, beans and other crops that 

 cannot stand an excess of moisture, but 

 for such crops as rice the height of the 

 water is the only guide. 



In countries where no rain falls and 

 the composition of the soil is known, 

 the amount of water to be used for each 

 crop can be accurately stated in acre- 

 inches. — Philippine Agricultural Re view, 

 June, 1908, Vol. I., No. 6. 



FURROW IRRIGATION. 



By Albert Howard, m.a., a.r.c.s., 

 Imperial Economic Botanist. 



One of the first questions that has to 

 be considered in connection with experi- 

 mental work in the field in India is the 

 best means of applying irrigation water. 

 The present paper is written with the 

 object of recording the writer's expe- 

 rience in this matter at Pusa during the 

 last three years. 



The usual methods of watering plants 

 in India are well known and need not be 

 described in detail. Where water is 

 abundant, as for example in the Canal 

 Colonies of the Punjab, the surface is 



divided up into beds (Kiaris) and flooded. 

 In well irrigation, in the United Pro- 

 vinces, a similar method is used, except 

 that here the kiaris are much smaller 

 in size. In gardens, basin and trench 

 irrigation are to some extent employed, 

 but it has often appeared to me that 

 much remains to be done in India to 

 improve this latter system of watering. 



The disadvantages of flooding the 

 surface are well known. Besides the 

 destruction of the tilth and the forma- 

 tion of a surface skin (papri) which 

 becomes hard and impervious on drying, 

 this method leads to a great loss of water 

 by evaporation. Moreover, in many 

 cases, percolation is slow, as the air in 

 the soil can only escape very slowly 

 laterally. Further, flooding the surface 

 often leads to an infertile condition of 

 the soil, due possibly to the partial 

 destruction of the bacterial flora thereof. 



In order to overcome the disadvan- 

 tages of surface flooding and also to 

 economise water, a method has been 

 devised which combines the advantages 

 of furrow irrigation, basin irrigation 

 and irrigation by lateral seepage, ard 

 at the same time allows of a proper 

 surface tilth being maintained. The 

 method can be applied both to orchards 

 and to crops like tobacco, ganja, cotton, 

 patwa, etc. It has been found to be 

 particularly valuable in the case of 

 newly-planted fruit trees and for crops 

 like tobacco and ganja, which have to 

 be transplanted in the field from the 

 nursery. 



In orchards the method adopted is as 

 follows :- - 



A trench about a foot wide and four 

 inches deep is laid off parallel to the 

 rows of trees. Each tree is then sur- 

 rounded by a similar furrow-ring, the 

 position of the ring corresponding to the 

 outer spread of the branches; In newly- 

 planted trees the inside diameter of the 

 furrow-ring is from 3 to 4 feet. The 

 rings are joined up to the longitudinal 

 trench by short connecting trenches by 

 means of which the rings can be cut off 

 by an earth fillet from the longitudinal 

 trench. The following diagram will 

 make the arrangement clear :— 



C 



B 



