438 MR. J. B. LAWES, DR. GILBERT, AND DR. PUGH ON 
paratively large amount of Nitrogen, is one of the best preparations for the after-growth 
of wheat. On the other hand, it is equally true that fallow—one important effect of 
which is to accumulate within the soil the available Nitrogen of two or more years for 
the growth of one—and adding nitrogenous manures, have each much the same effect in 
increasing the produce of the Cereal crops. 
B.—Yield of Nitrogen per acre when Wheat is grown in alternation with 
Beans, or with Fallow. 
The striking and interesting fact, that the growth (and removal from the land) of a 
highly nitrogenized Leguminous crop, and fallow, have each the effect of increasing the 
amount of produce, and with it the yield of Nitrogen per acre, of a succeeding Cereal 
crop, is briefly illustrated by the summary of direct experimental results given in the 
following Table :— 
Tasez ITI. 
Showing the Amount of Nitrogen obtained per acre, in Wheat grown consecutively, in 
Wheat alternated with Beans, and in Wheat alternated with Fallow. 
Period of Experiment ten years, 1850—1859 inclusive. 
Nitrogen per acre, lbs. 
Total. | Average annual. 
Beans —10 crops consecutively we tne Manure sssssesessseseseesovens a469 oa | 
with Mineral Manure ....0...ssseceees 510°6 51-1 
‘ ’ 10 Crops consecutively.............00+0.| 234°0 23°4 
Wheat—without Manure { 5 Crops alternated with Fallow...... 219°3 | 43-9 or 21°9 
Wheat) _. 5 Crops alternated with Beans ...... 225°8 | 45-2 or 22-6 
Beans \ without Manure 5 Crops alternated with Wheat...... 2445 | 48°9 or 24°5 
Wheat] _. ' 5 Crops alternated with Beans ...... 207°0 | 41-4 or 20-7 
Beans \ Aiels ohareee) easier 5 Crops alternated with Wheat...... 227-2 | 45°4 or 22°7 
It is seen, then, that ten consecutive crops of beans, without manure of any kind, 
gave an average annual yield of Nitrogen, per acre, of 34-7 Ibs.; and ten consecutive 
crops with “mineral” but without nitrogenous manure gave an average annual yield, 
per acre, of 51-1 lbs. 
During the same period, ten consecutive crops of wheat without manure of any 
kind gave annually 23:4 lbs. of Nitrogen, or less than half as much as the beans. 
with mineral but without nitrogenous manure. Again, extending over the same 
series of years, five crops of wheat alternated with fallow gave, taking the average of 
the five years under crop, 43:9 lbs., and on the average of the ten years, 21:9 Ibs. per 
acre, per annum, of Nitrogen. That is to say, the wheat alternated with fallow gave, 
taking the average of the five years of its growth, nearly twice as much Nitrogen 
annually as the wheat grown after wheat in the same seasons. ‘The total Nitrogen 
cbtained, per acre, over the ten years, was, however, pretty much the same in the two 
