482
Nature of the crop 483
Amounts of fertilising ingredients removed from the soil by
different crops 484
Capacity of crops for assimilating manures 486
Difference in root-systems of different crops 488
Period of growth 489
Variation in composition of crops 490
Absorption of plant-food 490
Fertilising ingredients lodge in the seed 491
Forms in which nitrogen exists in plants 491
Bearing of above on agricultural practice 492
Influence of excessive manuring of crops 492

CHAPTER XXIII.--MANURING OF THE COMMON FARM CROPS.

Cereals 493
Especially benefited by nitrogenous manures 494
Power of absorbing silicates 494
Barley 495
Period of growth 495
Most suitable soil 496
Farmyard manure not suitable 497
Importance of uniform manuring of barley 497
Norfolk experiments on barley 497
Proportion of grain to straw 498
Wheat 499
Rothamsted experiments 500
Continuous growth 500
Flitcham experiments 500
Oats 501
A very hardy crop 502
Require mixed nitrogenous manuring 502
Arendt's experiments 503
Avenine 503
Quantities of manures 504
Grass