312 EXPERIMENT STATION KECOED. 



An examination of the brownisli colored water collected, in low places where 

 large quantities of saw palmettos were scattered over the surface of the ground, 

 showed that while the water was distinctly acid, there was only the faintest 

 indication of tannic acid. This indicates that there is no foundation for the 

 common belief that the acid condition of Florida soils is due to tannic acid 

 leached from the saw palmetto. 



Report on fertilizer experiments on swamp soils, li. Harcourt (Ann. Rpt. 

 Ontario Agr. and Expt. Union, 30 (1908), pt). 37-39). — This is a brief summary 

 of information which has been collected for a number of years on the compo- 

 sition and productiveness of Ontario swamp soils. 



It has been observed " that where the swamp material lies over clay, and 

 particularly if it is not so deep but that some of the clayey materials may 

 become mixed with the top soil, good results are obtained. But when the 

 materials are not sufficiently decomposed to form a soil that will hold water 

 when the land is tile-drained, or when the subsoil is a sand, the results are 

 invariably poor." 



Out of 44 samples of swamp soils analyzed only 3 were found to contain 

 less than 1 per cent of lime and none was noticeably sour or acid. " Eight 

 of the samples contained less than 0.3 per cent of potash and only 6 had less 

 than 0.2 per cent of phosphoric acid. In nearly every case the lowest per- 

 centage amounts of these plant food constituents were found in swamp soils 

 lying over sandy subsoils. The quantities of potash and phosphoric acid 

 found in these soils are not large; but the average results show fully as 

 much as will be found in most of our good arable soils, and some of them 

 contain an unusually large amount. They also contain from four or five to 

 ten times as much nitrogen as our ordinary soils. Consequently, it is evident 

 that the unproductiveness of these soils can not always be charged to the 

 lack of plant food. 



" The results of determinations of humus show that decomposition has pro- 

 ceeded further in some cases than in others, and, as -the nitrogen and possibly 

 the greater part of the mineral constituents are held in organic combination, 

 it is quite probable that in many instances decomposition does not take place 

 rapidly enough to furnish a full supply of food to the plant." 



In fertilizer experiments with oats on the swamp soils the use of potash 

 as a rule increased the yield, especially in cases in which lime was not used. 

 Lime and phosphoric acid had little effect. 



Swamp soils, R. Harcourt (Ann. Rpt. Ontario Agr. Col. and Expt. Farm, SJf 

 (,1908), pp. 66-68). — This has been noted from another source (see above). 



On the process of separation of soluble mineral products from plant 

 residues, .S. Kravkov (Ztiiir. Opiiitn. Agron. [Russ. Jour. Expt. Landa\], 9 

 (1908), No. 5, pp. 569-626; aJjs. in Chcm. Zcnthl., 1909, 1, No. 6, pp. Ji58, .'/59).— 

 This is an account of a series of systematic studies of the mineral constituents 

 dissolved by water from plant residues such as leaves, straw, hjiy, and roots 

 before and after decomposition. 



The processes of interaction between the products of the decomposition of 

 organic remains and the constituents of the soil, S. Kravkov (Zhiir. Opuitn. 

 Agron. [Russ. Jour. Expt. Landw.], 10 (1909), No. 1, pp. 1-3 'f). — In continua- 

 tion of the investigations noted aboAS, an attempt was made to determine the 

 changes in the chemical composition which soil undergoes under the influence 

 of the soluble products of the decomposition of plant residues. 



From the results of experiments on a rather light sandy chernozem and on a 

 gray forest soil the author concludes that where the conditions are such that 

 the soluble coustitueuts are rapidly removed from the soil there is a progressive 



