16 



BARN FIELD 



Series 







With 



No Nitrogenous 



Manure. 



c 



With 

 Rape-cake. 



AC 



With 



Rape-caJ<e A 



Ammonium Salts. 



D 



No Minerals. 



^Superphosphate. pl]Superphosphate 

 i |v£n and Potash . 



Superphosphate , Pota^ , 

 Magnesia and Soda. 



Fig. 4.— Mangolds. Effect of various Mineral Manures. Average 

 Produce of Roots per acre, 1876-1902. 



Effect of Artificial Manures with Dung. 



A comparison of Strip 2 with Strip 1 shows the 

 superphosphate and sulphate of potash to the dung 

 manures apphed to Strip 1. A heavier crop and a healthier plant 

 obtained, especially where a large amount of nitrogenous manure is used. 

 Since in the earlier experiments it was found that superphosphate had no 

 beneficial effect when used with dung, we can put down the superiority of 

 Strip 2 over Strip 1 to the sulphate of potash which is now used. 



effect of adding 

 and nitrogenous 



IS 



Effect of Manures upon the Texture of the Soil. 



On the strong Rothamsted soil several of the manures employed have 

 an injurious action upon the texture of the soil and often prevent a 

 satisfactory tilth being obtained in the spring, to the great injury of the 

 crop. This is particularly seen where no organic manure is used ; both 

 dung and rape cake tend to keep the land in good condition. Of the 

 artificial manures nitrate of soda and sulphate of potash have the worst 

 effect upon the land, making it very sticky when wet, and hard and caked 

 when dry. Superphosphate on the contrary promotes a friable tilth. 



