iio6 



Notes on Agriculture Abroad. 



[FEB., 



The method described by Wirz* in 191 8 and Wencksternf 

 in 1 91 9, though requiring similar apparatus, is quite different 

 in principle. It is a method of producing sweet silage under 

 pressure that has lately come much into vogue in Switzerland. 

 The system generally adopted, though numerous modifications 

 are in use, is that of the Herba Co., Rapperswil. As regards 

 Wirz, the chief point of interest is that he traces the progress 

 of the movement from the stack silo to the container. He is 

 not, however, very explicit as to the methods adopted in the 

 latter process. From Wenckstern, however, we learn that the 

 silos, which are erected under cover, should not be more than 

 about 15 ft. high by about 14 ft. square, with a capacity of about 

 3,000 cubic ft. The corners inside are rounded. The press 

 has a pressure of about 8 to 10 cwt. per square yard, some- 

 times as much as 16 cwt. being applied with good results. 



The most explicit directions are iven as to every stage in 

 the process. The grass must be wilted but not really dry, 

 though dry enough to exude no moisture when twisted in the 

 hand ; the correct moisture content is about 74 per cent. The 

 wilted grass must be loosely spread in the silo, about i| to 2 

 yards deep at a time, and allowed to rise quickly to a temperature 

 of 50° to 60° C. (122° to 140° F.) ; the temperature must then be 

 checked by compression either by means of a fresh layer or 

 with the press. The material must never at any time be 

 trodden ; when pressed there must be no interstices or hollows 

 in any part of the mass. The reasons given for these directions 

 are that the slight drying of the grass assists loose layering, 

 which in turn admits air and oxygen, thus inducing plant 

 respiration which leads to rapid heating. Acetic acid fer- 

 mentation is active between the temperatures of 18° and 35° C. 

 (65 ° and 95 ° F.) and is quite checked at 50 ° C . (122 ° F.) . Butyric 

 acid fermentation is most active between 35^ and 37° C. (95° 

 and 99° F.) and ceases at the latter temperature. Lactic acid 

 fermentation begins at from 30° to 35° C. and can go on after 

 50° C. (122° F.) is reached. This, then, is the right stage at 

 which to check any further development and to secure the lactic 

 acid described by Wenckstern as " the farmer's friend." The 

 impression left after reading the directions is that the success 

 of the system depends on too many minute observances — too 

 much thermometer reading and sampling by taste and smell. 

 The system, as Wenckstern suggests, is more likely to be used 



* Wir^: : -Die ..Siissfutterbereitung.— Zurich, 191 S. 



t Wenckstern : Das neue Siisspressfutter verfahren in Silos mit Selbsttatiger 

 Pressvorrichtung. — Berlin, 191 9. 



