Continuous (^rowing of Wheat. 
240 
raised to 2 cwt. per acre. The addition of superphosphate and 
a little sulphate of potash (d) to the 1 cwt. nitrate of soda gave 
over 23 bushels, or 11 bushels more than the unmanured 
produce, while doubling the nitrate (9a) only gave 3 bushels 
more, the omission of nitrate (9b) as usual taking the yield 
at once down to the unmanured level. 
The results with sulphate of ammonia were, more par- 
ticularly when taken in conjunction with the action of lime, 
very striking. With 100 lb. sulphate of ammonia used alone 
(2a) there was almost total failure, a thick growth of spurry 
taking the place of the wheat. But the single application 
(in Jan. 1905) of 5 cwt. lime per acre (2aa) produced 10'5 
bushels of wheat per acre, while on plot 2b, which last had 
lime (2 tons per acre) in December 1897, the yield was 24‘2 
bushels or double the unmanured crop. The repeating of this 
dressing of lime in 1905 (2bb) did not do the good expected, 
as the yield was markedly lower. The flag of the straw was 
quite browned, and the ear had a dark colour, indicating that 
the application of lime had been overdone. Possibly this 
may have been due to the fact that the later application of 
lime was in the form of ground lime. When used with 
minerals (5a) 100 lb. sulphate of ammonia continued to yield 
a good crop, though in places there were signs of failure, and 
on plot 5b, which had in 1905 1 ton of lime to the acre in 
addition to the minerals and sulphate of ammonia, the yield 
was increased by 2'3 bushels and amounted to 33*7 bushels per 
acre. Where the double quantity (200 lb.) of sulphate of 
ammonia was used the crop continued to show the decrease 
marked in recent years, but the application of 10 cwt. of lime 
to the acre in 1905 on plots 8aa, 8bb, gave an increase of 
crop, this increase amounting to 19 bushels with 8aa, and 10*6 
bushels with 8bb, the results in each case considerably exceed- 
ing the produce of the plots 9a and 9b similarly manured with 
nitrate of soda. Comparing plots 10a and 11a, the presence 
of phosphates appeared to be more necessary than that of 
potash, though it is still early to draw conclusions on this 
point. 
Rape dust did not do nearly as well as in 1906, though 
it was superior to farmyard manure, which, once again, gave a 
low yield. The farmyard manure plot was weaker in straw and 
“ knocked down ” more than any of the others. It would appear 
not at all unlikely that the soil has, by the repeated dressings, 
received too much farmyard manure, and that the effect of its 
continued use is to bring about a too “ open ” condition of the 
land. The crop was rather better than in 1906, but this can 
hardly, as yet, be put down to the ploughing in of the manure 
in place of applying it as top-dressing. 
