February, 1909.] 



fact that the soil in the vicinity of San 

 Antonio is heavy, together with the 

 comparative rarity of high winds, 

 makes it possible to maintain an effec- 

 tive dust mulch and to accumulate in 

 the soil enough moisture to carry on a 

 crop to maturity even if little rain falls 

 during its growth. 



After the dust mulch has been des- 

 troyed by a rain, evaporation from the 

 supply of water in the soil begins as 

 soon as the rain ceases, and in cases 

 where the weather immediately follow- 

 ing the rain is hot and windy this 

 loss of moisture becomes exceedingly 

 great. On the heavy soils of San Anto- 

 nio a light rain, as for instance 0*1 to 0*4 

 inch, reduces rather than increases the 



173 Scientific Agriculture. 



total amount of soil water. This is 

 apparently due to the fact that such 

 light rains are only sufficient to establish 

 capillary connection between the sur- 

 face soil and the moisture in the lower 

 soil, and before the surface is dry 

 enough to permit cultivation some of 

 the moisture has been drawn from the 

 supply below and dissipated into the 

 air. A rain of less than 0"1 inch is 

 usually sufficient to establish such capil- 

 lary connection, and is therefore harm- 

 less. Even a heavy rain, unless followed 

 immediately by cultivation to renew 

 the dust mulch, may result in a reduc- 

 tion rather than in an increase of the 

 amount of soil moisture. Such a case 

 is illustrated by Table 1. 



Table 1.— Soil Moisture in an Orchard and a Cornfield Cultivated on 

 June 5 and June 3, 1907, Respectively, illustrating the Effect of 

 Early Tillage after Rain, 



Depth in feet. 



Average 



Orchard. 



Cornfield. 



Moisture 



Moisture 



Moisture 



Moisture 



May 28. 



June 6, 



May 28. 



June 6. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



22'3 



22-2 



18-3 



20-0 



21-2 



21-2 



18.4 



18-6 



19-6 



17'8 



15-6 



153 



21-0 



20-4 



17-4 



180 



On May 29, P2 inches of rain fell, 

 which should have raised the moisture 

 content of the upper 3 feet of soil 2*7 per 

 cent, had it all been absorbed. Seven 

 days after the rain, in the absence of a 

 dust mulch the moisture content of the 

 first 3 feet in the orchard was 0'6 per 

 cent, less than it had been before the 

 rain. Had this field been harrowed two 

 or three days after the rain there would 

 have been an increase in the amount of 

 water in the soil instead of an actual 

 decrease. In a near-by field of corn 

 which was cultivated two days earlier 

 than the orchard there was an increase 

 of 0-6 per cent, of moisture over what 

 was in the soil May 28.— Extract from 

 U. S. Department of Agriculture, B. of 

 PL Ind. Bulletin, No. 13, September, 

 1908. 



[The work of the San Antonia (Texas) 

 Experiment Station in 1907.] 



[The lesson of this article badly needs 

 taking to heart in Ceylon.— Ed.] 



FARMYARD AND ARTIFICIAL 

 MANURE. 



Tillage as a Manure. 



application to coconut cultivation. 



Is it more profitable to use famyard 

 manure— i.e., cattle and other dung 

 mixed with straw, waste herbage, and 

 refuse properly decomposed in a pit — 

 than artificial is a question that should be 

 of great interest to all planters and agri- 

 culturists. Artificial or special manures 

 contain but few of the constituents re- 

 quired for plant nutrition, and are 

 applied to those crops which require 

 more of a certain ingredient than the soil 

 contains. Farmyard manure on the 

 other hand is a general manure, con- 

 taining all the constituents required 

 by plant life. Artificial manures are 

 much quicker in action than farmyard, 

 and are an essential auxilary to general 

 manures. A general manure may be 

 used year after year on the same land, 

 but artificials, if used exclusively, would 



