Nov. 8,1915 Relation of Sulphur Compounds to Plant Nutrition 
237 
EXPERIMENTAL WORK 
Beginning in 1911, experiments have been conducted in the green¬ 
house to determine the influence of sulphates and sulphur on the growth 
of some common farm crops. Seven different crops representing three 
different orders have been included in the work up to the present time. 
They were distributed by orders as follows: Cruciferae—radish (Raphanus 
sativus), rape (. Brassica napus); Gramineae—oats (Avena sativa ); barley 
(Hordeum vulgare); Leguminosae—red clover (' Trifolium pratense) , bean 
(.Phaseolus vulgaris ), pea ( Pisum sativum). It should be said of plants 
grown in this way that they sometimes do not develop so well as under 
field conditions. The lessened light of winter as compared with sum¬ 
mer, for example, retards growth, and in the early fall and late spring 
the day temperatures are likely to become excessive. Also, possibly 
owing to the protection from wind and the absence of insects, the plants 
rarely seed well. Despite these influences, however, our crops have 
grown well in most cases and in some cases have developed luxuriantly. 
It is true, moreover, that in all cases the effect of varying fertilizer 
treatments is reliable for comparison, since each crop, save the food 
supply, was grown under conditions as uniform as possible. 
method of investigation 
The soil used in this work was the Miami silt loam which predomi¬ 
nates on the University Hill Farm. It was obtained by removing the 
surface vegetation and selecting the surface soil to a depth of about 4 
inches. This material was then sifted through a X'-inch screen and 
thoroughly mixed. There was practically no loss in the sifting, as 
hardly a stone was found and the sifted product was smooth and of 
excellent quality. 
A total analysis of the soil showed the following composition, based 
on the dry matter: Nitrogen (N), 0.15 per cent; phosphorus pentoxid 
(P 2 0 5 ), 0.14 per cent; sulphur trioxid (S0 3 ), 0.04 per cent; calcium car¬ 
bonate (CaC 0 3 ), 0.33 per cent; humus, 1.38 per cent. 
The humus was determined by the official methods of analysis of the 
Association of Official Chemists. 1 Fifteen kilos (33 pounds) of this soil 
were placed in rectangular cypress boxes 16 inches long, 14 inches wide, 
and 5 inches deep. Seven different fertilizer treatments were tried in 
duplicate boxes of the soil, as follows: 
Boxes Nos. 
1-2. Control (no fertilizer). 
3-4. Complete fertilizer: Gm, 
Tricalcium phosphate (Ca 3 (P 0 4 ) 2 ). 12. o 
Potassium chlorid (KC 1 ). 4-5 
Sodium nitrate (NaN 0 3 ).. 10. o 
1 Wiley, H. W. f et. al. Official and provisional methods of analysis. Association of Official Agricul¬ 
tural Chemists. U. S. Dept. Agr. Bur. Chem. Bui. 107 (rev.), 272 p., 13 fig. 1908. 
