86 THE CHEMISTRY OF THE FARM 



of maturity reached at harvest, it has necessarily a 

 great influence both on the composition and quality 

 of the crop. A fine malting barley, rich in starch, 

 can only be produced in a fine season ; any^ im- 

 perfect ripening, produced either by cold, wet weather, 

 or by the premature drying of the grain during severe 

 drought, will result in the production of grain poor 

 in starch and relatively rich in nitrogenous matter (see 

 further, pp. 16, 137). 



Each crop requires more or less a different climate 

 for its perfect development ; a knowledge of the kind 

 of climate best suited to each crop is of great service 

 in selecting crops for any particular district. Thus 

 wheat requires hot and dry weather for its ripening 

 period, while oats will ripen in a moist atmosphere. 

 Mangels require heat, and can resist drought, while 

 turnips develop best in a cool, moist air. Oats and 

 turnips thus best suit the Scotch climate, while wheat 

 and mangels are better fitted for the south-east of 

 England. 



The soil best furnished with plant food is the one 

 which will yield the best results in adverse seasons, 

 the crop having a greater amount of vitality, and being 

 able to turn to the best advantage the short periods of 

 favourable weather that may occur. Poor soils yield 

 their best results in seasons of slow but continued 

 growth, the crop having a longer time to collect the 

 scanty supply of food which the soil contains. In 

 hot seasons, with an early harvest, only soils well 

 supplied with food can produce full crops. 



The character of the autumn and winter has a con- 

 siderable influence on the crops of the following summer. 

 In a wet autumn or winter the soil may lose nitrate? 



