506 On the Growth of Barley by different Manwes, ^r. 



turnip, this result is easily explained by the fact, that much 

 larger crops of turnips were in each course taken from the super- 

 phosphated, than from the unmanured rotation land. Consistently 

 with this (omittin<2; the first course when the existing condition of 

 the land obviously somewhat interfered with the result in all 

 three rotations), it is on the other hand seen, that the fed super- 

 phosphated turnips gave larger succeeding crops of barley than 

 the fed unmanured ones. 



It is worthy of remark, that on the entirely unmanured rotation 

 plot, the barley after the fed-on-turnips was, in the last two 

 courses, when the turnips had amounted to less than 2 tons per aci'e 

 total produce, even somewhat less than where the corresponding 

 crops of roots had been carted from the land. This was possibly 

 due to more injury being done to the texture of the land by the 

 treading of the sheep, than was compensated by the trifling 

 amount of manure from the consumption of such meagre crops 

 of turnips. 



In the case of the full manured turnips, as well as the super- 

 phosphated ones, there was, however, always a considerable 

 increase in the succeeding barley by feeding the turnips on the 

 land. As was to be expected, too, the barley after the highly 

 manured turnips, whether carted off or fed on the land, was 

 always heavier than after the corresponding superphosphated 

 ones. On the other hand, the difference in the amount of barley 

 depending on whether the turnips were fed on the land or 

 removed, was considerably greater where the superphosphate of 

 lime alone was employed for the roots. This was partly due, 

 as already implied, to the fact that the removed superphosphated 

 turnips had drawn from the land more of certain constituents 

 not supplied in manure, and therefore left the soil poorer in 

 them for the succeeding barley, than where the full manure, or 

 even no manure whatever (with the consequent meagre turnip 

 crops), was employed. But as there was evidence that, where the 

 highly manured turnips had been fed on the land, it was in too 

 high a condition to yield, as seasons go, so full an amount of 

 produce in proportion to the manure as when the latter was less 

 in quantity, it is obvious that the difference in result by feeding, 

 w^ould be more striking after the superphosphated turnips — 

 where by carting-off the exhaustion was greater, and by folding 

 the manuring was not too high — than where, as on the highly 

 manured plot, both the exhaustion by the removal of the turnips 

 was less, and the manuring by feeding was more excessive. 

 Here again, it may be remarked in passing, the figures teach us 

 how sensitive is the barley crop to the vicissitudes of season, and 

 how liable to injury under them, when manured beyond a certain 

 somewhat narrow limit. 



