THE SHRINKAGE OF MARKET HAY. 11 



one case (experiment 5, p. 5) clover hay, which lost only 22.6 per 

 cent by shrinkage, was partly musty at the end of the experiment. 

 Considering that the normal water content of cured hay amounts 

 to 13 per cent, the percentage of water in this particular lot at the 

 time it was put in the barn was 32.66 per cent. 



The Kansas station 13 has found that alfalfa containing as much 

 as 24 per cent of water will cure out properly in the stack. In the 

 semiarid West it may be safe to stack hay containing more than 24 

 per cent of water, while in the South and parts of the East, where 

 the humidity is greater and unfavorable weather often prevails, it 

 may not be safe to put up hay with such a large water content. 



THIRD FACTOR— NORMAL WATER CONTENT WHEN CURED. 



The normal water content of cured hay is the third important fac- 

 tor to be taken into account. Shrinkage in hay practically ceases 

 when the water content reaches a certain point which varies with 

 climate (See "Average," Table II), and not until then is the curing 

 process finished in barn or stack hay, which may then be rightly 

 classed as well-cured, marketable hay. As the water content of hay 

 baled from the windrow or cock is sometimes above normal, it is 

 subject to shrinkage in the bale. The average normal water content 

 of hay is the amount of water usually contained in hay after it has 

 passed through the "sweat" or "heat" in the stack or barn and is 

 ascertained by averaging all available water-content analyses. In 

 the case of timothy (see Table II), 221 water analyses have been 

 averaged, giving an average of 11.6 per cent. In the cases of other 

 hays fewer analyses are available, which probably accounts, in part 

 at least, for the variation in the figures presented as representing 

 the average water content of the different grass and legume hays. 



FOURTH FACTOR— MINIMUM WATER CONTENT. 



Sometimes hay becomes very dry. In fact, in the West "dry" 

 hay is discriminated against on account of the loss by shattering and 

 because it is thought to lack palatability. The water content in 

 "dry" hay is shown in Table II, under "minimum." When 

 the percentage of water in hay is so low that the air will no 

 longer absorb any of it, the hay is said to contain a minimum amount 

 of water. The minimum water content which is the fourth factor 

 depends upon the humidity of the air, length of time the hay is 

 exposed to such air, and the amount or bulk of hay in the stack or 

 barn. 



To lower the natural minimum it is necessary to subject the hay to 

 artificial drying, as is done in the laboratory when making a deter- 

 mination of dry matter. The figures given in the table do not imply 



" Kansas Agricultural Experiment Station, B ull. 155, 1908. pp. 258-259. 



