SOILS FERTILIZERS. 



921 



The followint; taltlp shows the lu.-un nvcraso results ohUihicd in the c-heniieal 

 examination of tlieso various kinds of soils: 



Arcra(/c results of chemical unali/ses of Scania soils, 1900-1906. 



Hygroscopic water 



Loss on ignition 



Humus '• 



Total nitrogen 



Nitrogen in humus 



Alumina soluble in sulphuric 



acid 



Alumina soluble in hydro- 

 chloric acid 



Kaolin- AI-O3 



Corresponding to kaolin 



Phosphoric acid 



Iron and alumina 



P205:FeL-03-t-Al203::l: 



Potash 



Lime '' 



Calcium carbonate (CaCOa)'^ 

 Sediment (Wagner) 



Clayey soils. 



Heavy 

 (4 sam- 

 ples)." 



Per ct. 

 3.930 

 8.380 

 4.200 

 ..30O 

 V.IOO 



8.640 



4.190 



4.4.50 



11.200 



.097 



13.880 



143.000 



.272 



.520 



0.000 



63.100 



Medium 

 (20 sam- 

 ples)." 



Per ct. 

 2.950 

 6.740 

 4.000 

 .260 

 6.500 



6.370 



3.640 



2.730 



6.800 



.080 



10.740 



138.000 



.204 



.470 



.260 



46.000 



Light 

 (61 sam- 

 ples)." 



Perct. 

 2.330 

 5.010 

 3.;)00 

 .210 

 6.000 



3.800 



2.0.50 



1.750 



4.300 



.085 



6.770 



80.000 



.144 



.440 



.330 



32.700 



Sandy soils. 



Clayey 

 (20 sam- 

 ples)." 



Per ct. 

 1.700 

 5.050 

 3.600 

 .220 

 6.100 



2.060 



1.340 

 .720 



1.700 

 .095 



4.390 



52.000 



.106 



.300 



.230 



22.500 



Pure 

 (12 sam- 

 ples)." 



Per ct. 

 2.040 

 5.070 

 3.800 

 .190 

 5.000 



.600 



.470 

 .130 

 .300 

 .097 

 2.910 



33.000 

 .080 



• .270 

 .200 



18.400 



Humus soils. 



Low in 

 humus 

 (8 sam- 

 ples)." 



Per ct. 

 3.45 

 13.14 



1.80 

 2.29 



.07 

 6.88 



98.00 

 .14 

 .50 

 .49 



35.20 



Pure 

 (10 sam- 

 ples)." 



Perct. 



8.97 

 39.58 



.99 

 .49 



.16 



4.40 



28.00 



.12 



4.41 



" In some cases the figures given do not represent the exact number of samples 

 analyzed. 



** Reduction factors : 0.5 for heavy and 0.6 for medium clays, 0.7 for light clays and 

 for clayey sandy soils, and 0.75 for sandy soils. 



" Averages for 4 to 4(5 different samples of the various classes. 



The main results of the fertilizer trials made on these soils with small 

 grains, potatoes, root crops, and meadows are summarized by the author and 

 studied in connection -with the analytical data obtained. The following is a 

 brief summary of the conclusions drawn from these trials: 



Nitrogen. — Although the nitrogen content of the mineral soils was very high 

 (average 0.23 per cent), the large majority of the soils responded especially 

 to nitrogen fertilization, and as a general rule, only the soils containing more 

 than 0.5 per cent niti'ogen (and more than 10 per cent loss on ignition) either did 

 not react or reacted only faintly. In the other soils (the mineral soils proper) 

 no relation was to be observed between the need of nitrogen fertilization, 

 as indicated by the yields obtained, and the nitrogen content of the soils, 

 whether the absolute nitrogen content (percentage in the soil) or the relative 

 nitrogen content (percentage in humus) was considered. The explanation is 

 doubtless that the utilization of nitrogen by crops does not primarily depend 

 on the amount of nitrogen in the soil, but on the amount of assimilable nitro- 

 gen found therein and on the intensity of the nitrification process. The colori- 

 metric method of O. Reitmair is recommended by the author for the study of 

 the relation of nitric nitrogen in soils and the results obtained in fertilizer 

 tests. The results thus obtained may tend to explain the difference in the ac- 

 tion of nitrogenous fertilizers on different soils and lead to the still more 

 imiiortant result, to determine by soil analysis (i. e., in the laboratory) whether 

 a high or low nitrogen fertilization will pay best in the case of a particular 

 soil. 



Phosphoric acid. — The percentage content of phosphoric acid can be very 

 low, even toward 0.03 per cent, and still medium crops of at least the small 

 grains ))e obtained without i)hosi)hori(' acid fertilization. .Most of the soils 

 (about two-thirds of them) responded to applications of i)hosphoric acid fer- 



