ARTICLE XXXI. -THE SOILS AND SOIL-FORM I^IRS OF THE 

 SUBANTAHCTTO ISLANDS.* 



By B. C. Aston, F.I.C, Chief Chemist, Department of Agriculture. 



INTRODUCTION. 



Generally speaking, the soils of New Zealand, excluding those of swamps, littoral 

 situations, or limestone districts, are deficient in those humus or peaty substances 

 so essential to intensive agriculture. The manner in which the humus content of 

 British soils is supplemented is largely by frequent applications of stable manure. 

 In a country where the stock are not stabled to any extent, and where the absence 

 of cities precludes the possibility of obtaining large quantities of stable manure or 

 other organic refuse, the problem of maintaining a proper proportion of humus in 

 the soil is one which sooner or later must be faced. One of the most feasible ways of 

 supplementing the store of organic matter in the soil, and one practised with marked 

 success in America, is the ploughing-in of quick-growing green crops. The principle 

 is a difficult one for the New Zealand farmer to act upon. The temptation to turn 

 his stock into a paddock of clover or mustard, instead of ploughing it underground, 

 is too hard to resist, except it be in very small areas, as an experiment, which, how- 

 ever successful, is too soon forgotten. 



This report deals wdth the composition of types of soil which, so far from 

 suffering from the above defect, are at present unsuited to the uses of higher 

 agriculture owing to a plethora of that very constituent which is lacking in the 

 mainland. 



Should the facts outlined in these pages throw any light on the reason why these 

 southern islands are so bountifully supplied with humus, it may suggest methods 

 of treatment by which the stores of humus in the mainland soils may be profitably 

 reinforced. 



PEAT AND HUMUS. 



The terms " humus " or " peat " are synonymously used by most authorities.-f 

 Little is known of the precise chemical composition of the different forms of decom- 



* The investigation is incomplete. A number of specimens remain to be analysed, particularly 

 those soils and rocks containing rare earths, which require more detailed investigation. In a subse- 

 quent paper it is intended to treat of the mainland humus soils, and to summarise the results of the 

 whole research. 



t It is, of course, often impossible to conjecture how large areas of vegetable matter have originated, 

 but it is advisable to as far as possible restrict the term " peat," in the substantive, to plant-remains 

 presumably formed in stagnant water, and containing a very small proportion of pure ash. 



