December 25, 1919] 



NATURE 



423 



ment, there are certain distinctions which must be 

 Ivcpt in view. In a meadow the plants are allowed 

 to grow up to full maturity, whereas in a pasture 

 thev are cut over daily, or at least very frequently, 

 bv the grazing of the animals. It is difficult to arrive 

 at a decision as to whether a larger gross weight of 

 dry material is got from a given area treated as pas- 

 ture, in contrast to being hayed, but the probability is 

 that the aggregate quantity is greater. Take the 

 analogy of a patch of lucerne. Cut three or four 

 times in the season, it may yield six tons of dry 

 matter per acre, cut once it would certainly yield 

 much less. Or take the case of cocksfoot ; this 

 springs so quickly in the aftermath that the foliage 

 ma\' shoot up 6 in. almost in as many days, whereas 

 there would be no such growth were the hay not cut 

 over. It is a matter of observation, too, how quickly 

 red clover springs up after cutting, and trees and 

 shrubs which may be growing only a few inches 

 annuallv when unrestrained may send up stool shoots 

 several feet in length if cut over. It is difficult, how- 

 ever, to bring the question to the test of figures. 



If there is any doubt as to the greatej weight of 

 drv matter produced under a system of grazing, 

 there can be none in respect of its digestibility. This 

 would appear to be the reason why sheep and cattle 

 will fatten on a pasture, whereas the animals would 

 only remain in store condition on the herbage if made 

 into hay. 



At one time experiments on the improvement of 

 pasture took the form of temporarily enclosing an 

 area, to which different methods of treatment were 

 applied and of determining the results in terms of 

 hay. Supplementary to such quantitative determina- 

 tion, chemical analysis and botanical separations were 

 often made, but it is evident from the work of the 

 investigators already quoted that the results so ob- 

 tained may be a very untrustworthy index of the 

 feeding value of the herbage. In any case, the com- 

 petition between the various classes of plants may be 

 verv different in a hay field and in a well-grazed 

 pasture. Again, in a hay field the produce is reaped 

 and cleared off with all'the' plant food which it con- 

 tains. In' a pasture, on the other hand, there is the 

 dailv conversion of vegetable substance into manure 

 and its immediate return to the land. Reflections of 

 that sort induced me in i8ci6 to arrange a series of 

 experiments where a direct appeal was made to the 

 animal. We all know that among a lot of animals 

 there are certain individuals which possess idiosyncra- 

 sies which result in their thriving- better or worse than 

 the others. By careful selection, however, and 

 especiallv by keeping them under observation for a 

 probationary period, this objection may be largely 

 eliminated. ' The greater the number of animals, the 

 more completely is any disturbance due to individual 

 peculiarities got rid of, and for this reason sheep are 

 usually employed in preference to cattle. No one 

 who looks into the details of these "manuring for 

 meat " experiments can doubt that, not only in broad 

 outline, but even in the finer details, the results are 

 perfectly trustworthy. Involving as they do con- 

 siderable outlay on fencing, water, weighing machines, 

 etc., and necessitating the use of large areas of 

 uniform land, such experiments were not likely to be 

 undertaken with great frequency, but I have been 

 able- to find reports of nine in England, twelve in 

 Scotland, two in Ireland, and one in New Zealand. 

 Two of them are situated at Cockle Park, of which 

 the original in Tree Field has now completed its 

 twentv-third season, while the other in Hanging 

 Leaves has a record of sixteen years. 



The outstanding feature of these experiments is the 

 great and profitable effect of phosphates. In this 

 NO. 2617, VOL. 104] 



muterial the larmer is placed in possession of an 

 agent ol pruduciiou tne enects ot wnich on the out- 

 put of meat, milu, and work from the pastures ol 

 this country are only limited by the supplies. In 

 many cases the increase of meat is treblea, and e\en 

 quaarupled, with a return on the original outlay that 

 runs into hundreds per cent. .As between the various 

 sources ot phosphate there is unmistakable evidence 

 that basic slag is the most etlective, not only in 

 respect of aggregate yield of meat, but also, and 

 more particularly, when the net financial return is 

 considered. This conclusion is also reached by Car- 

 ruthers and Voelcker in a long series of pasture 

 experiments carried out in 189^-99 for the Royal 

 Agricultural Society of England. In these experi- 

 ments, however, the effects were only estimated by 

 ocular inspection. The primary efiect of phosphate's 

 is due to the marked stimulus that they give to the 

 growth of clovers and other Leguminosa-, and as 

 these plants revel in a non-acid soil the alkaline 

 character of basic slag appears exactly to suit their 

 requirements. 



In regard to the quantity of phosphatic manure 

 that can most effectively be employed per acre, it 

 would appear that in the case of inferior pasture a 

 heavy initial dressing, say 200 lb. of phosphoric acid 

 or more per acre, is likely to be nearly twice as effec- 

 tive as half this dressing, and therefore actually much 

 more profitable. To secure the best results the 

 Leguminosae must be rapidly brought up to their 

 maximum vigour, so that they may fully occupy the 

 ground before the grasses have had time to react to 

 the effects of the accumulated nitrogen. 



One of the most striking results of these pasture 

 experiments is the long period over which the action 

 of phosphates persists. Even at the end of nine years 

 the meat-producing power of half a ton per acre of 

 basic slag is far from being exhausted. It is not 

 suggested that this persistent action of slag — and no 

 doubt this applies also to any other effective phosphate 

 — is due to unappropriated residues. It is much more 

 probably due to two other causes : (a) to the fact that 

 on a pasture, in contrast to a meadow, manurial 

 elements are kept in circulation from the soil to the 

 plant, and from the plant to the animal, and so, to 

 a large extent, back to the soil again ; and (b) to the 

 accumulation of nitrogen in the form of humus. 

 Poor, unprofitable grass is chiefly associated with 

 clay, and it is fortunate that it is precisely on such 

 land that clover responds so markedly to phosphatic 

 manuring. But conspicuous results have also been 

 obtained on deep peat, on light stony loam, on thin 

 chalk, and on cfialk covered by clay with flints. 

 Middleton has very fully discussed the conditions 

 under which phosphatic dressings may be expected to 

 give results, and ascribes an important place to soil 

 moisture, on which white clover is directly very- 

 dependent. The only conspicuous case of failure of 

 phosphates to improve pasture was encountered in 

 Norfolk, where a " manuring-for-mutton" experi- 

 ment was started in 1901. The soil at that station 

 was a hot, dry, sandy gravel containing 6a per cent, 

 of sand, and there both the basic slag and super- 

 phosphate were unable to produce any improvement. 

 Wood and Berry attribute this result partly to the 

 presence of abundant natural supplies of citric soluble 

 phosphoric acid, but chiefly to lack of moisture. In 

 reporting on the R..'\.S.E. experiments Carruthers 

 and Voelcker in 1900 had already directed attention 

 to the dependence of basic slag on soil moisture. 



We may now look at the effect of supplementing 

 phosphates with certain other substances. .'Knd, first 

 of all. as regards potash. .At most of the manuring- 

 for-mutton stations, both in England and Scotland, 



