AN ABNORMAL ORCHARD SOIL 



11 



Aluminum sulfate lowered the pH much less and the growth of the plants was 

 not affected. In fact, when applied to soil from the limed complete fertilizer 

 plots it appears to have increased growth. (Table 9.) 



The addition of organic ammoniates increased soil nitrates and growth (Fig- 

 ure 5) and for some reason aluminum sulfate greatly increased soil nitrates. 



The effect of sulfur was further studied in 1932 (Table 10 and Figure 6) with 

 even more disastrous results, perhaps because soil from the unlimed plots was 

 used. With the heavier applications of sulfur the plants were soon killed. Or- 

 ganic ammoniates applied to limed but unfertilized soils increased growth. 



Soil from an orchard (Block A) where the apple trees were making a satisfactory 

 growth, but on an equally acid soil, was used in one test. Acidifj'ing the soil with 

 sulfur was even more injurious to the plants. 



No tests were made in 1933, but in 1934 further studies of the effect of other 

 organic materials, including manure and peat, were made. All these organics 

 contained approximately equivalent amounts of nitrogen per pot, except the 

 manure which probably carried only about two thirds as much. Sulfur in lesser 

 amounts than in previous years was also used. Again, the organic ammoniates 

 increased growth even with 8 grams of sulfur, but inorganic ammoniates, except 

 possibly nitrate of soda, were of doubtful effect. Peat seemed ineffective in all 

 the combinations used. (Table 11.) 



Table 8. — Pot Cultures, 1930. 



Table 9. — Pot Cultures, 1931. 



* Five pots received each treatment, 

 meaning: 

 No treatment 

 N Nitrate of soda 

 P Superphosphate 

 K Potassium chloride 

 L Magnesium limestone 



The figures indicate grams per 17 kilos of soil. 



The letters and figures in this column have the following 



Ca Calcium carbonate 



S Ground sulfur 



Am Ammonium sulfate 



Mg Magnesium sulfate 



Al Aluminum sulfate 



