25 



It has also been suggested to mix the sulphate of ammonia 

 with the seed before solving. This, however, is risky, and 

 likely to hinder the germination of the seed. Recent ex- 

 periments of Vandevelde* have shown that substances dis- 

 solved in the water supplied to seeds often decrease the 

 power and energy of germination ; and this is, of course, 

 exactly the state of things when the manure and seed are 

 mixed together. The same experiments proved the impor- 

 tant fact that, of the three groups of salts, nitrates are most 

 injurious to germination, chlorides less so, and sulphates 

 least harmful. 



The steeping of the seed in a solution of sulphate of am- 

 monia before sowing has been suggested ; and as long ago as 

 1843, a communication was made to the Royal Agricultural 

 Society! detailing most favourable results from this method. 

 It is unsafe in practice, however ; for the vitality of the seed 

 is easily injured in this way. 



Dressings of sulphate of ammonia, or of any nitrogenous 

 manure in which the nitrogen is readily available for the 

 plant's use, are uncertain in their action if given too late in 

 the life of the crop. 



It has been stated already that one effect of the appli- 

 cation of nitrogenous manures is to retard the ripening of 

 the plant. If this takes place late in the crop's life, its 

 growth may go on so long that, in the case of a corn crop, it 

 ripens badly, and in late districts the harvest is put off till 

 the comparatively unfavourable weather of the late autumn ; 

 or, in the case of roots, the crop has to be taken up or fed in 

 an immature condition, when, of course, its feeding value is 

 less than it should be. 



Another effect of the use of nitrogenous manures will be 

 remembered viz., the increased formation of leaf. In the 

 case of a late dressing, this result is exaggerated, much of the 

 energy of the plant being consumed in this way, and the 

 amount and quality of the seed being deteriorated. Follow- 

 ing as a secondary result from this rankness of growth, is 

 the great tendency of corn crops to go down or be laid, when 

 they have been dressed with nitrogenous manures late in the 

 season of growth. Such crops are also more likely to be 

 injured by rust and mildew, or blight. 



It is worth while to point out here that the unfavourable 

 effects mentioned are not the result of the late application of 

 sulphate of ammonia only, but are common to all kinds of 

 concentrated, readily available, nitrogenous manures. In 

 fact, sulphate of ammonia is on the whole less likely to do 

 harm to the crop, even when used injudiciously, than nitrate 

 of soda. 



* Bot. Centr., 69. 



f Campbell, " Journal of the Royal Agricultural Society of England," 



Vol. IV. 



