1920] FIELD CROPS. 825 



fall grazing was, as a rule, offset by the value derived from the pasturage, but 

 ill the Xordenfjelske region the reduction in hay yield was somewhat greater 

 than the corresponding quantity of grass consumed in grazing. When the yield 

 of rowcn was over 350 lbs. per acre, mowing the crop proved the more profitable. 

 In all regions concerned, grazing reduced the yield of hay most when grass- 

 lands newly laid down were pastured. 



The shrinkage of market hay, H. B. McClure (U. S. Dept. Agr. Bui. 875 

 (1920), pp. SS, fig. 1). — A resum6 of experimental data on the shrinkage of hay, 

 together with a discussion of the factors affecting the determination of shrink- 

 age and losses, and suggested methods of milking hay to prevent unnecessary 

 shrinkage. The author disparages the indiscriminate use of conflicting terms 

 in the hay industry and offers definitions dealing with hay in the several 

 stages in the process of curing. The data reviewed and the recommendations 

 may be summarized as follows : 



The percentage of shrinkage in hay is influenced by water content when cut, 

 maximum water content when stored, normal water content when cured, 

 miuirmim water content, atmospheric humidity, and effect of time. In experi- 

 ments conducted during the last 30 years to determine the rate of shrinkage 

 in hay in the barn and stack, the loss in weight was found to range from 0.29 

 to 42.2 per cent and the gain in weight ranged from 0.4 to 10.7 per cent, 

 making a total variation of about 53 per cent. 



All efforts by investigators to determine the average rate of shrinkage, in 

 order to formulate a definite rule to be used at harvest time to calculate the 

 percentage of " dry " or marketable hay, have failed because of the effect of 

 such factors as variation in the time of cutting, methods of curing, and the 

 weather, which will always cause a wide difference in the percentage of shrink- 

 age in hay on individual farms within a given territory. The experiments 

 >liow that there is no correlation between the lapse of time and the percentage 

 of loss by shrinkage. 



The author holds that the widespread publication of experimental data 

 showing comparatively large losses by shrinkage, during several months, has 

 been misleading, especially to producers, because the investigators failed to 

 point out that the greater part of the loss occurs before the hay is in proper 

 condition to be baled or marketed and that the loss, which is practically of water 

 only, is simply a part of the natural curing process, and therefore should have 

 no commercial value. 



If hay is marketed in the proper condition, shrinkage does not affect the 

 profits of the producer until after the final curing stage, known as fermenting 

 or sweat stage, has been finished and the water content has become normal. 

 Continued dry weather which lowers the normal water content of marketable 

 hay may cause a shrinkage which affects the producer's profits, but this 

 loss is liable to be offset by the increase in water above normal, which takes 

 place during the damp weather when hay ab.sorbs water from the air. Shrink- 

 age causes an actual loss to rhe shipper or dealer when he buys and stores 

 hay containing more than the normal water content for well-cured barn or stack- 

 cured hay. 



Practically no loss of dry or nutrient matter occurs during the shrinkage 

 of hay while in the barn or stack, provided the hay has been properly cured 

 before it is hauled from the field. Undercured hay, containing an excessive 

 amount of water, is liable to become so hot in the barn or stack that it will 

 become discolored, charred, or in extreme cases, entirely burned up by spon- 

 taneous combustion. 



Under certain conditions necessitating an adeQuato. full sizeil, experienced 

 haymaking crew, the use of a definite, eflicient, and practically unchangeable 



