81 



these crops, the cost of cultivation, harvesting, and marketing. 

 In estimating the sum he can afford to pay for the residue of 

 manure left by his predecessor, he will also recollect that he 

 will not himself be repaid in crops for two years after his 

 entrance on the farm. 



There is clear evidence that the effect of the liberal 

 quantity of cake applied in these experiments was confined 

 to the first three crops (two years) after its application ; the 

 wheat, which comes at the end of the rotation, shows no 

 benefit from the cake applied to the turnips ; and this is 

 equally the case whether the wheat is preceded by a legumi- 

 nous crop or by a bare fallow. 



5. Rotation Experiments at Woburn. 



In the rotation experiments at Woburn an attempt has 

 been made to determine the comparative effect of two manures 

 prepared respectively by the consumption of equal weights of 

 decorticated cotton-cake and maize-meal, and which ought 

 therefore to contain very different quantities of nitrogen. 

 The investigation has been continued during twenty years : it 

 can hardly be said to have attained its object, but the results 

 are nevertheless extremely instructive. 1 



The rotation experiments at Woburn commenced in 1877. 

 They were so arranged that four rotations in different stages 

 proceeded simultaneously ; each crop in the rotation was thus 

 grown every year. 



During the first eight years the roots were manured with 

 dung made by feeding bullocks in deep stalls or boxes, one 

 set of bullocks receiving l,0001bs. of decorticated cotton-cake, 

 and the other set 1,000 Ibs. of maize-meal; the turnips, chaff, 

 and litter supplied being in both cases the same quantity. 

 The cake employed would contain about 50 Ibs. more nitrogen 

 than the maize, but the actual difference in the resulting 

 manures was not ascertained. In eight crops of roots thus 

 manured in successive years, the excess yielded by the cake 

 over the maize manure averaged only 12| cwts. per acre. 

 The roots were fed off by sheep, and the crop of barley 



1 A detailed report on these experiments has been published by Dr. J. A. 

 Voelcker, Journ. R&y. Agri. Society, 1897, 622. 



