MANURING IN THEORY AND PRACTICE. 



351 



pared with, that dug nine or eighteen inches deep in 

 the previous year, is here showti ; — 



Table showing Effects of Dissolved and TJndissolvbd 

 Fhosphates upon Swedes at Sarelaw, and upon Yellow 

 Turnips at Fumplierston, in the Season of 1880. 



Undissolved Phosphates, 



These facts indicate that the extent and direction 

 of the miderground range of the Turnip is very much 

 dependent on the mechanical condition of the soil : 

 the rapidity of bulb-formation and the amount of 

 crop are greatest where the land is deeply tilled. The 

 land dug nine inches deep shows a slight superiority 

 over that which is ploughed, and shows the character 

 of the conditions required in Turnip culture. It is 

 universally known that tilth is of the highest im- 

 portance to the favourable formation of bulb in root 

 erops ; and the best relation of bulb to leaf, and in 

 fact the best acreage yield of bulbs, is in the lighter 

 soils, where there is comparatively little obstruction 

 to the development of fibrous root, and it is in these 

 that the special efficacy of superphosphate has been 

 most observable. And if the Turnip is to be valued 

 for its bulb-formation, the aim of the gardener must 

 be not to increase the above-ground organs of col- 

 lection (the leaves), but the underground fibrous 

 roots. 



EflFect of Phospliates.— Much controversy 

 has recently occurred regarding the action of dis- 

 solved and undissolved phosphates, as aiiected by the 

 amount of free phosphoric acid supplied to the soil 

 by various artificial manures ; it will be admitted by 

 most horticulturists that, in order to be food for 

 plants, phosphate of Ume, like other constituents 

 of plant-food, must be soluble to some extent in 

 water, or in the liquid which passes through the 

 medium of the root into the plant. The greater effi- 

 cacy of phosphate of lime in bones in comparison 

 with coproUte powder entirely depends upon its finer 

 state of aggregation, and consequently upon its 

 greater solubility in the form of bone-dust. 



The following results, from Dr. Andrew Aitkin's 

 report,, of experiments conducted by the Highland 

 and Agricultural Society of Scotland, atHarelawand 

 Pumpherston, confirm the opinion that there is great 

 economy in using dissolved phosphates, rather than 

 the raw material, upon those and similar soils. 



Thus, the increase in the crop due to the dissohang 

 of the phosphate is, at both stations, about 20 per 

 cent. ; the totfil amount of dry matter per acre is at 

 Harelaw 15 per cent, more, and at Pumpherston 25 

 per cent, more on the plots which received dissolved 

 phosphates,- proving that the increase of crop is not 

 due to water chiefly, but also to solid matter, or sub- 

 stances useful as food. 



Effect op Manures on Swedes and Mangels. 



Growth of Swedish Turnips, Year after Tear, on the 

 same Land at Mothamsted. Fifteen Years, 1856- 

 1870. A.verage Produce per ^cre per Annum. 



