THE GARDENERS' CHRONICLE OF AMERICA. 



273 



SULPHUR AS A FERTILIZER. 



NEW IDEAS IN PLANT FEEDING. 



Remarkable discoveries regarding the use of sulphur 

 as a fertilizer have been made both in Europe and Amer- 

 ica during the last two or three years. Since the articles 

 telling of these new ideas have been published in tech- 

 nical journals not accessible to the average man interested 

 in agriculture, it seems worth while to gather the impor- 

 tant facts together so that they may be available to the 

 practical agriculturist. 



The work of E. B. Hart and W. H. Peterson of the 

 University of Wisconsin will first be considered, as it is 

 in many respects the most important. These men, while 

 investigating the supply of sulphur in feeds and its re- 

 lation to wool production, found it necessary to deter- 

 mine the amounts of sulphur in common crops used as 

 feeds. Their determinations showed such startling dis- 

 crepancies from Wolfe's tables and other standard sources 

 as to the amounts of sulphur found in plants that they 

 made a thorough investigation of the subject. 



Formerly when the amount of sulphur in a plant was 

 to be determined the plant was ignited and the sulphur 

 in the ash was reported as the amount of sulphur in the 

 plant. Sulphur, however, in certain forms is volatile, 

 and when exposed to a high heat is driven off in a gaseous 

 form and lost. In this way we secured our wrong ideas 

 regarding the importance of sulphur in plants. It is con- 

 ceded by all agricultural chemists that sulphur is abso- 

 lutely indispensable to the growth of plants ; they did 

 not suppose that it was required, except in extremely 

 small amounts, hence the common statement that the soil 

 already contains plenty of sulphur for the crops. Hart 

 and Peterson went at the problem in a different way. 

 They found the sulphur in the air-dry plant by a modern 

 method of analysis. This prevented the losses caused by 

 ignition and gives us our first reliable information on the 

 subject. 



A few extracts from a table prepared by them will 

 probably give the practical man the clearest idea of the 

 importance of their discoveries. In the first column we 

 have the pounds of sulphur which would be removed per 

 acre according to the standard authorities previous to 

 1911. The second table shows the amounts of sulphur 

 actually removed, and the third the amounts of phos- 

 phoric acid removed per acre. The last table shows the 

 relative importance of sulphur and phosphoric acid. The 

 comparison is surprising in its results. 



I II III 

 Sulphur 



According Sulphur Phosphoric 



Crop. to Wolfe's Actually Acid 



Removed Removed Removed 



Pounds Pounds Pounds 



per Acre, per .\cre. per Acre. 



Wheat (30 bu.) 3.55 15.7 21.1 



Barlev (40 bu.) 5.1 14.3 20.7 



Oats (45 bu.) 6.2 19.7 19.4 



Corn (30 bu.) 5.35 12.0 18.0 



Alfalfa (9,000 lbs.) 37.8 64.8 39.9 



Turnip 44.4 92.2 33.1 



Tobacco 21.0 16.0 



Cabbage 62.8 98.0 61.0 



Potatoes (3,600 lbs.) 11.5 21.5 



It is seen at a glance tliat sulphur in special plants 

 such as alfalfa, turnip and cabbage is greatly in excess 

 of phosphoric acid, and in all cases it occurs in large 

 quantities. Not only is this the case, but sulphur is not 

 more abundant in the soil than phosphoric acid, what 

 is gained by rainfall being lost by drainage. From these 

 facts it is evident that if it is necessary to add phosphoric 

 acid to the soil, it is also necessary to add sulphur. This 

 has been done unconsciously to a certain extent, since 

 superphosphates and gypsum, also ammonium and potas- 

 sium sulphates, all contain sulphur. These fertilizers 

 were not used on account of the sulphur contained in 

 them, however, but for other reasons. The new facts 

 concerning sulphur help to explain the beneficial action of 

 some of these substances as compared with others. It is 

 suggested that the difference may be due more to the 

 sulphur than the difference in solubility, as formerly 

 supposed. Hart and Peterson naturally concluded as a 

 result of their investigations that sulphur must be sys- 

 tematically added to the soil in order to secure a rational 

 system of fertilization. 



European agricultural scientists have also been giving 

 attention to sulphur as a fertilizer during the last two or 

 three years. The fact that they have approached the 

 matter from an entirely different point of view makes 

 their results all the more interesting and valuable. Their 

 methods have been invariably to use some form of sul- 

 phur directly as a fertilizer in pot or field experiments. 

 So far as is known they were not aware of the work of 

 Hart and Peterson ; at least, they seemed to have the idea 

 that sulphur acted indirectly, affecting the soil bacteria 

 in some way rather than directly as a plant food. 



Maizeres added sulphur at the rate of 250-300 kila- 

 grams per hectare (2,226 to 4,452 pounds per acre) to 

 his fields of potatoes and beets. Large increases in the 

 yields followed, and he decided the value was due to two 

 causes — the disinfecting action of the sulphur and the 

 direct entering of the sulphur into the composition of the 

 plant. 



The use of sulphur ii' Germany during 1909, according 

 to E. Chancrin and A. Desriot, resulted in the reduction 

 of potato diseases and an increase in yield. Their opin- 

 ion as to the reason for the beneficial action was that the 

 sulphur might cause a partial sterilization of the soil, 

 similar to that caused by heat and other agents. 



An article in a German agricultural paper states that 

 experiments show a reduction of 50 per cent, of the total 

 number of diseased tubers when the soil was treated with 

 flowers of sulphur. Not only was this true, but the con- 

 dition of the soil was improved and the yield increased. 



L. Degrully writes that experiments carried on in 1911 

 showed that 109 g. of sul])hur per square meter (about 

 975 pounds per acre) doubled the crop of beets and in- 

 creased the yield of turnips 33 per cent. A large part of 

 the sulphur appeared later in the soil as sulphates. He 

 supposed the benefit was due to the direct effect of sul- 

 phur on the plant. 



The practical trials of sulphur in Europe confirm the 

 laboratory work done in America and show conclusively 

 that sulphur is a factor to be reckoned with in a rational 

 fertilizer. It is a point the practical man should be fa- 

 miliar with, and take into consideration when deciding 

 on a fertilizer. Sulphur may be applied as flowers of sul- 

 phur, iron pyrites, gypsum, or in superphosphates, sul- 

 phates of potassium and ammonium, and stable manures. 

 It would be an interesting experiment to apply flowers 

 of sulphur directly to plots of turnips, onions, cabbage 

 and potatoes, as the first three require particularly large 

 amounts of sulphur and the latter has responded to the 

 use of this element in a gratifying manner according to 

 actual trials. — Rural New Yorker. 



