90 Field Experiments of Crude German Potash-Salts, &,'€. 



arrangements of the different plots, and tlie quantity and kind 

 of top-dressing employed : — 



Experiments with Crude Potash-Salts and Common Salt on Long Eed 

 Mangolds at Tubney Warren, Abingdon. 



Plots 



of 



J- Acre. 



Top-dressing per Acre. 



Number 

 of Roots 

 per Plot. 



Produce per 

 Plot. 



Produce per 

 Acre. 



Increase over 

 Plot 1. 



cwts. qrs. lbs. tons. 



No. 1 



„ 2 



„ 3 



„ 4 



-, 5 



., 6 



,. 7 



„ 8 



., 9 



„ 10 



„ 11 



„ 12 



Nothing* 



Common salt, 2 cwts. .. 

 Crude potash-salts, 3 cwts. 

 Common salt, 3 cwts. . . 

 Potash-salts, 1 cwt. 



Nothing* 



Common salt, 2 cwts. . . 

 Potash-salts, 2 cwts. 

 Common salt, 4 cwts. .. 

 Potash-salts, 4 cwts. 

 Common salt, 8 cwts. .. 

 Nothing* 



636 

 592 

 620 

 632 

 632 

 619 

 711 

 685 

 713 

 719 

 703 

 698 



12 15 

 18 3 24 

 1 18 



26 



1 13 



17 

 18 

 15 



13 



16 

 16 

 19 

 21 

 21 



2 24 

 2 2 



1 17 



2 5 



3 21 



14 2 14 



12 

 18 

 17 

 18 

 15 

 13 

 16 

 16 

 19 

 21 

 21 

 14 



cwts. lbs. 



2 76 



19 32 



8 24 



4 72 



7 36 

 



14 32 



10 40 



8 4 



10 100 

 18 84 



11 68 



tous. cwts. lbs, 

 Nothing." 

 5 14 80 



4 3 72 



5 8 



2 2 84 

 Nothing. 



3 9 80 

 3 5 98 



6 3 52 

 8 6 36 

 8 14 20 

 Nothing. 



* Average of 3 nothings . . 



tons. cwts. lbs. 

 13 4 64 



The preceding experiments suggest the following remarks : — 



1. The weights of the produce on the three plots not top- 

 dressed with either common salt or potash-salts show variations 

 amounting to 2 tons 9 cwts. per acre. Differences in the weight 

 of the produce on other plots amounting to 2^ tons per acre, 

 therefore have to be ascribed rather to the variable agricultural 

 condition of the different plots of the experimental field than to 

 the top-dressings used. 



2. The results obtained on Plots 2 and 7 evidently show that 

 such natural variations in the productive powers of the soil 

 really existed in different parts of the same field. Plots 2 and 7 

 were both top-dressed at the rate of 2 cwts. of common salt 

 per acre, whilst Plot 2 produced an increase of 5 tons 14 cwts. 

 80 lbs. over the average yield of the undressed plots. Plot 7 

 gave only an increase of 3 tons 9 cwts. 80 lbs., or 2 tons 5 cwts. 

 less. Tlae limit of variations in the weight of the produce of 

 Plots 2 and 7 it will be seen agrees closely with the difference 

 in the weight of mangolds on the undressed Plots 1 and 12. 



3. Making due allowance for the natural variation in the 

 productive powers of different parts of the same field, common 

 salt, it will be noticed in every instance, gave as good a result 

 as an equal weight of the more expensive crude potash-salts. 



4. It will further be seen that the larger doses of salt pro- 

 duced a greater increase than the smaller. Thus 3 cwts. of salt 



