Hastening The Drying Of Hay

Press, Volume XCIX, Issue 29324, 1 October 1960, Page 9

Hastening The Drying Of Hay

Tm main problem aaeociated with the preeervnMon of a tor-, age crop lake hngr b that of reducing Ha moisture nonierrt to a node level .lor storage while at the name tune minimising the loan of nutrient, which will inevitably occur' through continued respiration in the initial stages of curing and through SDoil&ffe as a Testih of adverse weather during thft curing period. In a recent address, Mr George Lindsay, lecturer in thg agricultural engineering department at Canterbury Agrictural . College had something'to say about stem crushing and bruising to hasten the drying process. It was common knowledge, he said, that plhkb leaves would lose their moisture more rapidly than would the stems. If, therefore, the moisture loss from the crop as a whole was to be speeded up it was to the stem that the major attention should be directed. The moisture which was trapped in the stem could be reteeeed by rupturing the stem well by use of stem-crushing machines, often known as hay conditioners, and flail-type forage harvesters. Stem crushers might be of two typeo—one in vjjhich the crop was crushed between a pair of plain steel rollers, which were in some cases rubber covered, and the other in which the crop was kinked between a pair of meshing corrugated rollers. “Results of experiments carried out at Lincoln College into the effect of kinking on the rate of moisture loss from lucerne cut

for hay have shown close agree ■ ment with the results of similar experiments overseas,” said Mr Lindsey. . “In general crushing or kinking has been shown to bring about a reduction of 20 to SO per cent, in the time during which a cut crop must be exposed for cuting before collection for storage. It has been shown that in

many cases the rate of drying of a crushed crop is slightly higher than that of a kinked crop, but the difference in drying rate has generally been very small.” Mr Ltodsay'said this week that work in Maine and elsewhere had Indicated that tbejbeneflt derived

from the plain rotter crusher was fairly critically dependent, on the spring pressure on the rollers, and whereas the performance of the kinker might not be quite as good as the plain roller crusher' at the optimum -setting, the setting of the kinker was not so critical. “Seyeral experiments Carried out to determine the effect of the flail-type forager in simultaneously cutting, and lacerating a crop have shown that - a crop treated in this way usually loses moisture at about the same rate as a crop treated with a crusher or kinker.

“The lacerated material may, under favourable conditions, dry out more rapidly than that which has been crushed, but if the windrow is too dense or. has been driven into the stubble it win dry out more slowly. The simplicity of the flail forager- as compared with the mowercrusher combination and the fact that cutting and bruising are done in the one operation would seem to indicate that the flail forager could become an attractive haymaking machine. Loss “However, another aspect of the use of crushers and of the flail forager is the degree to which this mechanical treatment of the crop may result in the loss of valuable leaf material. Expert ments at the University of Wisconsin sought to evaluate the proportion of small pieces in a freshly-cut crop of lucerne by separation on a wire sieve with a two-inch mesh. These experiments showed that about 5 per cent, of the crop as normally mown would pass through such a sieve, that from 8 to 15 per cent, of the material crushed between smooth rollers would pass through, and that for a crop cut with the flail forager, the proportion of small pieces varied according to the type of crop and the speed of travel and was between 18 and 45 per cent. These figures cannot be translated directly into quantities of material left behind on the ground by the pick-up baler, but they do give some indication of the relative severity of mechanical treatment by crushers and flail foragers. Some work in Massachusetts showed that the following weights of hay per acre were left behind the pick-up baler after different preliminary treatments: where the crop was mown and not crushed 1601 b, for a crop mown and crushed 2251 b and for a crop cut with a flail forager 3251 b.” In experiments at Lincoln College last season, results were obtained which showed close agree-

ment with the Wisconsin sievingloss figures and it is hoped'to make further investigations into this' loss in the coming season. “Much of this material which the pick-up baler fails to gather will consist of valuable leaves and small stems, but much of this loss may be avoided if it is picked up, not by a baler-type pick-up, but some other machine," said Mr Lindsay.

"The main disadvantages of these mechanical treatments which ate aimed at the more rapid removal of moisture from hay are first the expense, particularly in connexion with the mower and crusher approach, and second the fact that the crushed or bruised swath, if subjected to rain, seems to be adversely affected to a greater degree than the uncrushed swath. However, as the drying rate is so much improved by crushing, the chances of the cut crop being affected by rain before it becomes fit for collection are very much reduced.”