Field Experiments on Boot-Crops. 
381 
EscRiCK Potato Experiments in 1870. 
Tadm: showing; the Increase per Acre ou each Experimental Plot over the 
average produce of the Unmanured Plots, Nos. 1 and 5. 
Increase per Acre. 
tons cwts. lbs. 
4 16 58 
4 19 22 
4 7 26 
4 12 6 
0 19 22 
0 4 102 
5 3 34 
may be obtained if, instead of dung, a mixture of 4 cwts. of 
mineral superphosphate, 2 cwts. of potash salts, and 2 cwts. 
of sulphate of ammonia or nitrate of soda, be used per acre as a 
potato-manure. 
Relying on the experience of the past three seasons, I can 
confidently recommend this mixture as an excellent and well- 
paying potato-manure for light soils, when dung cannot be 
employed in sufficient quantity for that crop. 
2. In a dry season Peruvian guano produces but an incon- 
siderable increase in potatoes on light land. In more propitious 
seasons than that which characterised the past three years in 
many localities in England, the effect of guano, no doubt, is 
very different, and in good seasons guano will probably prove 
one of the best artificial manures for potatoes on light land. 
In 1868, 4 cwts. of Peruvian guano ga-te at Escrick an 
increase of only 1 ton 4 cwts. 1 qr. 17 lbs. ; and, in 1870, on 
similar soil to that upon which the guano was applied in 1868, 
only an increase of 19 cwts. 22 lbs. 
3. It will have been seen that neither sulphate of ammonia 
nor nitrate of soda materially increased the crop of potatoes in 
1870, thus confirming the general experience that in dry seasons 
ammoniacal or nitrogenous matters added to superphosphate and 
salts of potash are comparatively ineffective. 
riots. 
Manure used. 
Mineral Superphosphate 
and 
Potash-salts 
and 
Sulphate of AmmoDia 
Rotten Dung 
Mineral Superphosphate 
and 
Potash-salts 
Mineral Superphosphate 
and 
Potash-salts 
and 
Nitrate of Soda . . 
Peruvian Guano 
Mineral Superphosphate 
and 
Common Salt 
9 I Rotten Dung 
