STARCH CROPS 



III5 



putting the nitrate of soda on the tuber itself, it was meant to make its 

 utiHsation more immediate and thus prevent its being washed away. 



In these tests each plot had received per acre 54 lbs of P2O5 in the form 

 of slag and 40 lbs of KgO in the form of a potash salt. A control plot was 

 left without nitrogenous manure. To all the other plots manure was given 

 in equal quantities, i. e. 396 lbs of nitrate of soda or 264 lbs of sulphate of 

 ammonia. During the experiments not only was a determination of the 

 crop 3deld made, but many observations on the growth of the plants were 

 carried out. At the end of May the number of germinated plants was cal- 

 culated, and then every 10 days the height of the aerial parts of the plant 

 was measured. In addition, at the end of the field, from each plot 10 plants 

 were taken, and there were determined : i) the quantity and weight of the 

 tubers ; 2) the quantity and weight of the .stalks of each plant ; 3) the weight 

 of the aerial parts of each. 



The most important results of these experiments are summed up in the 

 appended Table. 



Results of Experiments. 



The comparison between the figures of the Table and the observations 

 made points to the following conclusions : 



i) vSulphate of ammonia gave a larger yield as compared with nitrate 

 of soda. 



2) A bigger crop was obtained by applying stilphate of ammonia 

 to the tuber than by spreading it before planting. 



3) By applying the dressing of nitrate of soda to the tuber, the 

 development of the potato in its first period of growth was considerabl> 

 retarded. As regards the crop, it appears nearly equal, whether the 

 nitrate of soda is applied to the tuber or is spread before planting. 



4) By giving half of the nitrogen in the form of nitrate of soda to 

 the tuber, and the other half in the form of sulphate of ammonia to the soil 



