Representative Transvaal Soils. 173 



Soils Nos. 760, 1620, and 2179 are derived from the Uaspoort 

 quartzites, and they are pracncally similar in their chemical composi- 

 tion to samples Nos. 1267, 1424, ']818, and 1294, which are derived 

 from the Magaliesberg- quartzites. Sample No. 2554 is from the 

 Timeball Hill quartzites and has unfortunately been only partially 

 analysed, its lime and available potash content is the same as the 

 average for the other quartzite soils, while its nitrogen is slightly 

 higher and a/ailable phosphate slightly lower than any of the other 

 soils, the analyses of which are quoted above. From their chemical 

 composition it will be seen that these soils are deficient in all the 

 essential plant foods — in fact they belong to the poorest class of soils in 

 the Transvaal. They are all of them particularly poor in nitrogen 

 and available phosphoric oxide, and with the exception of No. 1620 

 and possibly No. 1267 their potash content is also very low, they are 

 also in need of organic matter which must be worked into the soil to 

 improve their water retaining capacity. It is obvious from the 

 chemical analysis that in order to grow crops successfully on this type 

 of soil, the farmer would have to increase its plant food content by 

 gradually building up the soil, and in doing this lime would have 

 to be applied occasionally so as to avoid turning the soil acid. It 

 seldom pays on our Transvaal soils to apply a potash fertilizer so 

 that small dressings of this fertilizer are advised only when it becomes 

 clear by manurial experiments that potash is the limiting factor in 

 the particular soil under cultivation. Soils Nos. 760 and 2179 are 

 very low in available potash and would probably need a potash 

 fertilizer, in addition to fertilizers containing the other plant food 

 constituents, before a good vield can be expected The above state- 

 ments are made as a result of an interpretation of the chemical com- 

 position and a consideration of the mechanical analysis of the soil. 



Mmiurial Experiments. — Particulars as regards the crop returns 

 given by this soil may be gathered from the following manurial 

 experiments which were carried out by Mr. K. D. Watt (1). The 

 experiments were continued for two years and were carried out on the 

 farm Koedoespoort on a ooil from which sample No. 760 was taken. 

 The analysis of this sample is given in the above table. The crops 

 were maize (variety Chester County Mammoth) and cowpeas (variety 

 Black-eyed Susan) and were grown on two pieces, of land A and B, 

 respectively. The fields A and B were each divided into nine plots, 

 which were manured as is shown in the table. 



Unfortunately during the first year the rainfall was very low, and 

 probably quite inadequate for the requirements of the plants on such 

 a sandy porous soil. Plot No. 2 of field A was damaged, but the 

 following yields were obtained from the other plots. 



The yield of maize from field A is given in lb. of grain per acre, 

 while in the case of the cowpeas from field B the weight of the green 

 crop as well as the weight of the hay calculated to yield per acre is 

 ffiven : — 



