Studies of a Scottish drift soil

Abstract

1. An examination is made of some aspects of the replacement or exchange of bases by ammonium chloride solution, in a soil about which considerable information had been acquired regarding its physical, chemical, and mineralogical constitution, namely, the soil of Craibstone Experiment Farm, Aberdeen. Certain data in this connection are given.2. The “course of replacement” of calcium by ammonia, by successive applications of equal amounts of a normal solution of ammonium chloride is examined, according to the method of Gedroiz. Comparison is made between the results got for the Craibstone soil and those for a tshernoziem soil examined by Gedroiz. By means of graphs the agreement between the two soils as to the “course of replacement” is shown, and a distinction made between easily extractable calcium, and that more slowly removed in solution. The “course of replacement” of potassium and magnesium in the Craibstone soil is also examined.3. The presence of silicon, aluminium, iron and manganese is also noted in the extracts.4. The soil is also examined for “Total Exchangeable Bases” by extraction with normal ammonium chloride, according to the method of Hissink, with minor modifications.5. Exchangeable aluminium, iron, calcium, magnesium, manganese, potassium and sodium were found and in addition silicon was present in the extracts.6. The question of the presence of silicon, aluminium, iron and manganese in measurable amounts in extracts from acid soils is discussed.7. The relative proportions of exchangeable divalent and monovalent bases found were as follows. Calcium 85·02 per cent., magnesium 8·11 per cent., potassium 2·18 per cent., sodium 4·68 per cent. These results are in general agreement with those found for acid soils.

The genesis and development of two profiles of a drift soil in the north-East of Scotland. (With Two Text-figures.)

“…Mg comes next, and the relative proportions of K and Na present in the replaceable form are very small. This is in agreement with the results for acid soils in general (14). In the underlying layers there is a minimum in the relative proportion of Ca and a maximum in the relative proportion of Mg in layer 3, but in all cases Ca and Mg together constitute the bulk of the replaceable cations.…”

“…(iii) The replaceable bases were determined after treatment with N/l NH 4 C1 according to a method of Hissink(i9) with certain modifications (14).…”

“…Previous investigations on these soils have been described by Hendrick,Ogg and Newlands(ii,i2,13,14,26). In the lysimeter investigations described by Hendrick(i5,16,17), there is a record of all that has been added to the lysimeters and of all that has been removed from them in the drainage water and in the crops.…”

Study of the effects of fertilizers and rainfall on yields of crops grown in rotation

“…and with a generally good natural drainage. A full account of the chemical and mineralogical properties of the Craibstone soil will be found in various papers by Hendrick & Ogg (1916 and Hendrick & Newlands (1923,1925,1926. A mechanical analysis of the soil made at the commencement of the experiment indicates a clay content of 1-2 % as compared with approximately 30 % of fine sand and silt together.…”