The Survey and Classification of Land in New Zealand: A Basis for Planning.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 74, 1944-45, Page 185

The Survey and Classification of Land in New Zealand: A Basis for Planning. By Kenneth B. Cumberland. [Read before Canterbury Branch, March 1, 1944; received by the Editor, April 24, 1944; issued separately September, 1944.] Introduction. To satisfy the simple needs of all the world's 2,000,000,000 people is to go a long way to building peace on a solid foundation. The world of 1938 was a hungry world. War has but aggravated a condition which, although little publicised and less appreciated, was already present. If the architects of the new world-order find it possible to provide humanity as a whole with an ample and nutritive diet, they will banish a most potent primary cause of international strife and misunderstanding. To do this is a gigantic task, but one which is not beyond the limits of possibility. At bottom, it requires a wide and popular revaluation of the inherent importance of the land. In practice, it necessitates what amounts to an almost world-wide agricultural revolution. It demands a better use of soil in most parts of the world and—paradoxically enough—it requires higher use of land also in those parts of the world where agriculture has, until very recently, been considered most “efficient.” Another very disturbing fact characterised (especially) the inter-war years. It has been made abundantly apparent (first in the United States and later in practically all other parts of the world occupied sparsely during the past three centuries by an immigrant, European culture) that not only is the fertility of soil being rapidly depleted, but also that the soil itself is fast disappearing. Yet soil must long, if not permanently, remain the basis of expanded food production and of increasing numbers of industrial raw materials. New Zealand is concerned with both these problems. Soil exhaustion occurs in New Zealand whenever and wherever land is given inadequate care: such was the case on the bonanza grain farms of Canterbury during the 1870's and 1880's: such is also the case to-day in the Waikato, for example, where production is in decline. New Zealand's soil erosion problem is a formidable one. Its extent and nature have already been discussed (Taylor, 1938, D.S.I.R. Bulletin No. 77, 1939 and Cumberland, 1943). New Zealand is also—if less directly—concerned with the raising of world dietary standards. The Dominion can set the nations an emulative example of comfort, health and diet; and it can do much to serve that portion of humanity which is much less favoured, by increasing New Zealand's output and export of highly nutritive and most urgently required foodstuffs.

Fortunately, the conservation of soil, the restoration and increase of fertility and the expansion of productivity are intimately related. Where soil conservation is an established feature of national policy, it has been shown that the stabilisation of soil by erosion-resistant practices results in higher per-acre yields and is an important factor in helping to meet war-heightened demands (Bennett, 1943 and others). Soil conservation and maximum food production, alike, demand an understanding of the needs of the land, an appreciation of its capabilities and the most intelligent possible use of such land in accordance with its requirements. Proper use of land is governed by certain phsyical factors. Its capabilities, however, are affected by cultural factors—technological, economic and social. If a nation is to increase its primary production to the greatest possible extent, it must know its resources, both physical and cultural. A nation-wide stock-taking of New Zealand's resources is imperative if the Dominion is to play its proper part in, and make its maximum contribution to, the post-war world. The Problem. Had the war not intervened, New Zealand would have celebrated its centenary in 1940 with the preparation and publication of a modern “New Zealand Domesday Book.” The value of the Centennial Atlas if, and when, completed will be inestimable. But the atlas is intended to map the resources and productivity of the Dominion only on a small scale. More detailed information is necessary in order to have an adequate factual base on which to found plans for the future use of New Zealand's land and soil. Ideally, detailed methods of field analysis* A good example of detailed field analysis is that employed by the United States Soil Conservation Service and described by E. A. Norton, Soil Conservation Survey Handbook, U.S. Dept. of Agric. Misc. Publs. No. 352. Such detailed methods might be employed in New Zealand once reconnaissance survey has demonstrated the extent and location of problem areas requiring such treatment., applied from end to end of the Dominion, would be most desirable. Such methods have already been employed in the restricted area of the Heretaunga Plains (Connell, Kidson, et. al, 1939), and are being used to survey one important highly specialised aspect of land by the Soil Survey Division of the Department of Scientific and Industrial Research. These methods supply detailed, accurate, quantitative data; but they fail when applied to large areas and to all the important aspects of land, because of the time and cost involved. Time will be an important consideration in New Zealand if the Dominion is to be in a position to design an enlarged wartime or immediately post-war output of foodstuffs. The demand for factual information is likely to be early, urgent and insistent. On the other hand, traverse and generalised reconnaissance methods have been applied to certain limited aspects of land (Hilgendorf, 1935; Madden, 1940; Cumberland, 1941). For present purposes these are inadequate since, because of the methods employed, they are open to

inaccuracy and also because they are concerned, even in aggregate, with but few of the relevant data. The crux of the technical problem lies in bridging the gap between methods of detailed field analysis and those of reconnaissance, and in collecting at one time a variety of data—physical and cultural—which alone, when synthesised, are sufficient to suggest the most efficient, permanent and productive use of land. To survey present use of land is not in itself adequate. Present use (in the “new lands,” at least) is often inappropriate and inefficient, as the prevalence of deterioration, weeds and soil erosion in New Zealand, for example, clearly indicate. Contemporary use does not necessarily reflect the present capabilities or the ultimate potentialities of the land. Nor does a detailed soil survey provide a complete and satisfactory factual base in the absence of economic and social data. It appears necessary to the present task to consider the whole Dominion and to classify sufficiently small areas of land into broad categories adapted to different kinds and degrees of use; and this classification must be based on the investigation, the mapping, and the integration of all relevant factors. Such a classification would be immediately suitable as a basis for planning. Once international and national policies are announced, the most efficient use would then be known of the different categories of land in the light of such policy. (The Atlantic Charter already provides the framework for these policies; and, for New Zealand especially, the Hot Springs Conference has drawn the more essential features of the picture within that framework. Some of the many other advantages of this form of land classification are discussed below). The Suggested Solution: Notation, Procedure and Equipment. It is fortunate that a technique for making such a survey has been worked out, adequately tested and its value demonstrated. The Land Classification (formerly Geography) Section of the Tennessee Valley Authority devised a “unit area method of land classification” and applied it to over 41,000 square miles of the Tennessee drainage basin. The unit area method is described by Hudson (1936). The principal contribution of the present paper is an adaptation of this method to suit New Zealand's 103,000 square miles and to fit the great variety of regional conditions found in the Dominion. The original method proved to be a successful attempt to achieve the greatest possible accuracy and detail with field investigation within certain practical considerations of time and cost. Its unique qualities are: (1) the application of “fractional-code notations” (Jones and Finch, 1925) to land units of not less than 200 acres; (2) the use of aerial photographs as base maps, and (3) a consideration of all those items best calculated to serve land planning. The following adaptation is suitable for use with either aerial mosaics or the new One Inch Topographic Maps which by the end of 1943, were scheduled to cover 48,000 square miles—almost half the area of the Dominion. The adaptation has been tried out ten-

tatively near Christchurch (Plate 25). It will, of course, need some modification and considerable quantitive definition if, and when, it is applied to the constrasting variety of situations existing in New Zealand's relatively small area. Tables I, II, III, IV, and V, the notes, and the appended complete fraction illustrate the field recording and notation of the unit area method of land survey and use classification. Table I.—The Use of The Land. On the basis of which homogeneous unit areas are defined (noted on photographs and/or maps by the digits in the numerator of the long fraction). First Digit. Second Digit. Contemporary Land Use. Farm and Station Crops, Stock and Economy. 1. Agricultural Land (ploughed in farm year of survey). A. Cereals. 2. Pasture Land (in rotation where grass exceeds other crops in area). B. Root, Pulse and Green Fodder Crops (including main crop potatoes). 3. Pasture Land (permanent and semi-permanent). C. Grass and Clover for Seed. 4. Native Grassland (mainly tussock) [4] depleted (Raoulia). (4) deteriorated. D. Orcharding. 5. Scrub, Fern and Exotic Weeds. E. Market Gardening and Nurseries. 6. Forest Land (native and exotic). F. Other Intensive Crops (early potatoes, onions, tobacco, hops, etc.). 7. Unused (and not covered by other classes yet suitable for some form of use—e.g., afforestation, recreation). G. Store Sheep. 8. Unused (not suited to economic use of any kind). H. Sheep Breeding and Rearing. 9. Built-up Urban Area. J. Fattening of Sheep and Lambs. 0. Land outside Urban Areas occupied by Manufacturing or Mining Enterprises. K. Dairying. L. Station Cattle. M. Pigs and/or Poultry. Third Digit. Fourth Digit. Amount of Idle Land. Amount of Land rendered Unproductive by Weeds. 1. Little. 1. Little. 2. Limited. 2. Limited. 3. Considerable. 3. Considerable. 4. Excessive. 4. Excessive. Fifth Digit. Sixth Digit. Seventh Digit. Quality of Farmstead, Buildings, Plantations, Shelter, Equipment, Fences, etc. Kind of Native and Exotic Weeds Present. Size of Holdings. 1. Excellent. 1. Fern. 1. Very large [(1) excessive]. 2. Good. 2. Manuka. 2. Large [(2) excessive]. 3. Medium. 3. Other Natives. 3. Medium. 4. Poor. 4. Gorse. 4. Small. 5. Very Poor. 5. Broom. 5. Very small. [(5) too small]. 6. Blackberry. 7. Wild Briar. 8. Ragwort. 9. Other Exotic Notes. 1. 6, 7, 8, 9, 0 are to be noted by distinguishing numeral only. In the case of 9 and 0 this is preliminary to specialist study.

N Winton (Southland). 2A-B-K 11253/121122 2/1 = 111 Inland Ta ½ 5H444 4 2/524334 5/5 O

Bowenvale—McCormick's Bay, Christchurch.

2. 6 is not further characterised because forest types, timber values, etc., are adequately cared for by the State Forest Service. 3. The second digit may be expressed by joining several letters; though, to be included, each must have some considerable emphasis (see fraction example below). 4. Where several weeds are present in similar quantities, the sixth digit may be expressed thus:— 5 6 8 5. The third, fourth, fifth, and seventh digit descriptions require precise definition after the method has had a trial in different areas. Table II.—Land Classification. On the Basis of the Quality of its Contemporary Use (noted on photographs and/or maps by the numerator of the short fraction). Class. Qualities. 1. Unit areas characterised by the following features occurring individually or in combination: (i) Little (or no) idle land (ii) Little (or no) land rendered unproductive by weeds, (iii) Excellent buildings, equipment, etc., and (iv) any other evidence of a high standard of living. 2. Unit areas characterised by the following features occurring individually or in combination: (i) Little idle land, (ii) Land largely free from weeds, (iii) Good buildings, etc., and (iv) Any other evidence of a comfortable standard of living. 3. Unit areas characterised by the following features occurring individually or in combination: (i) Considerable idle land, (ii) A limited field coverage of weeds, (iii) Medium quality, buildings, fences, etc., and (iv) Other evidence of an average standard of living. 4. Unit areas characterised by the following features occurring individually or in combination: (i) Considerable idle or neglected land, (ii) A large amount of land occupied by weeds, (iii) Poor farmsteads and equipment, and (iv) Any other evidence of a moderate to low standard of living. 5. Unit areas characterised by the following features, occurring individually or in combination:—(i) Excessive amounts of idle land, (ii) Large areas rendered unproductive by weeds or abandoned, (iii) Very poor or limited buildings and equipment, and (iv) Any other evidence of a low and unsatisfactory standard of living. Notes. 1. This classification on the basis of the (contemporary) agricultural use of land is judged principally on the long fraction numerator indices 3, 4, and 5, and any other observable indications of prosperity (or otherwise) and of fitting (or unsatisfactory) use whether recorded or not. 2. The five classes are noted by numerals from 1 to 5 in the numerator of the short fraction which appears as a suffix to the long fraction.

Table III.—The Physical Conditions of the Land. On the basis of which homogeneous unit areas are defined (noted on photographs and/or maps by the digits in the denominator of the long fraction). First Digit. Second Digit Third Digit. Slope. Drainage. Soil Erosion. 1. Relatively level. 1. Thorough. 1. Little or no accelerated erosion. 2. Relatively level to undulating. 2. Adequate. 2. Soil erosion present—not serious. 3. Undulating to moderately hilly. 3. Poor. 3. Some obvious “slipping,” sheet wash, rilling, gullying, or wind erosion. 4. Hilly. 4. Very poor. 4. Much “slipping,” sheet wash, gullying, or wind erosion. 5. Steep. 5. Excessive. 5. Excessive “slipping,” gullying, sheet wash, or wind erosion. Fourth Digit. Fifth Digit. Sixth Digit. Rock Exposure. Soil Fertility. Soil Depth. 1. Little or none. 1. Exceptionally fertile. 1. Deep (more than 6ft.). 2. Limited. 2. Fertile. 2. Moderate (4ft.—6ft.). 3. Considerable. 3. Moderately fertile. 3. Adequate (2ft.—4ft.). 4. Excessive 4. Low in fertility. 4. Shallow (1ft.—2ft.). 5. Barren. 5. Very low in fertility. 5. Very shallow (less than 1ft.). Notes. 1. Other physical data are often necessary, most important amongst which are the climatic and meteorological. Sufficient information of this sort for almost any settled area is available in the Meteorological Office. Other data may be collected, but not necessarily recorded in the notation on field mosaics and map. 2. The descriptive terms suggested here practically all require precise quantitative or qualitative definition after trial. Table IV.—Land Classification. On the Basis of the Quality of its Present Physical Conditions (noted on photographs and/or maps by the denominator of the short fraction). Class Quality. 1. Unit areas characterised by the following features occurring individually or in combination:—(i) relatively level or moderately undulating surface, (ii) adequate or thorough drainage, (iii) little or no accelerated erosion, (iv) deep and fertile soil, and (v) little or no rock exposure. 2. Unit areas characterised by the following features occurring individually or in combination:—(i) relatively level to undulating surface, (ii) adequate or thorough drainage, (iii) little soil erosion present, (iv) moderately deep and fertile soils, and (v) limited exposure of rock. 3. Unit areas characterised by the following features occurring individually or in combination:—(i) undulating or moderately hilly surface, (ii) adequate or thorough drainage, (iii) soil erosion present or obvious (erosion control economically feasible), (iv) soils adequately deep and moderately fertile, and (v) limited rock exposures.

4. Unit areas characterised by the following features occurring individually or in combination:—(i) hilly surface, (ii) poor or excessive drainage, (iii) much obvious and serious soil erosion (continuation of contemporary practice would render control and rehabilitation economically impracticable), (iv) shallow soil, low in fertility, and (v) considerable rock exposure. 5. Unit areas characterised by the following features occurring individually or in combination:—(i) steep slopes, (ii) very poor or excessive drainage, (iii) much or excessive soil erosion (beyond the point where rehabilitation is feasible other than by profound changes of use—e.g. by afforestation or reforestation), (iv) shallow and stony soil of very low fertility and (v) excessive rock exposures. Notes. 1. The classes represent the judgment of the fieldman and are based on all observable physical factors whether recorded or not. 2. The five classes are noted by the numerals 1 to 5 in the dominator of the short (suffix) fraction. Table V.—Final Land Classification. On the Basis of the Economic Status of its People, its Inherent Agricultural Qualities, and its Physical Conditions (noted on photographs and/or maps by Roman numerals after the fractions). Class. Qualities. −I Unit areas which, in general, are unsuited to agricultural and pastoral use and occupance: of value only for forest use, for recreational, water conservation, and wild life reserves. These units are characterised especially by the following indices occurring individually or in combination:—(i) evidences of low standards of living, (ii) large holdings, extensive practices, (iii) excessive amounts of idle land, (iv) excessive amounts of weed-invaded land, (v) poor homesteads, and equipment, and dilapidated fences, etc., (vi) much bare rock, (vii) steep slopes, (viii) poor or excessive drainage, (ix) thin, stony, and infertile soils, and (x) excessive amounts of accelerated erosion. O Unit areas in which occupance is marginal and unstable and in which farm and station problems are critical. In the main these problems require marked readjustment and/or reorientation of economic activities and land use. These units are characterised especially by the following indices occurring individually or in combination:—(i) evidences of unsatisfactory standards of living, (ii) large or too small holdings, (iii) much idle land, (iv) considerable areas of weed invasion, (v) poor homesteads, inadequate equipment, shelter, etc., (vi) considerable bare rock, (vii) hilly to steep surface, (viii) poor or excessive drainage, (ix) shallow soils of limited fertility and (x) much accelerated erosion. + I Unit areas in which farm and station problems are moderately critical and in which occupance may be stabilised (and sometimes increased) and standards improved by intensive programmes of assistance, education and demonstration. These units are characterised especially by the following indices occurring individually or in combination:—(i) medium living standards, (ii) considerable idle land, (iii) limited to considerable areas of weed invasion, (iv) medium quality homesteads and equipment, (v) ill-designed farm layout and insufficient fencing, (vi) limited rock exposure, (vii) moderately hilly to hilly surface, (viii) adequate drainage, (ix) adequately deep soils of moderate fertility and (x) some obvious soil erosion amenable to control.

+ II Unit areas in which farm and station problems are not critical, and in which a stabilised occupance might be increased and intensified. Problems can readily be solved by programmes of instruction and demonstration. These units are characterised especially by the following indices occurring individually or in combination:—(i) good standards of living, (ii) little idle land, (iii) largely free from weed invasion, (iv) good homesteads and equipment, (v) little or no rock exposure, (vi) relatively level to undulating or moderately hilly surface, (vii) adequate drainage, (viii) deep and moderately fertile to fertile soils and (ix) soil erosion sometimes present but never serious. + III Unit areas in which no significant farm and station problems are apparent, and in which improved techniques and intensified use would most readily increase productivity and accommodate denser occupance patterns. These units are characterised especially by the following indices occurring individually or in combination:—(i) excellent living standards, (ii) little or no idle land, (iii) free from weeds, (iv) excellent farmsteads, fencing and facilities, (v) no rock exposure, (vi) relatively level to moderately undulating surface, (vii) adequate or thorough drainage, (viii) deep, fertile, or exceptionally fertile soils and (ix) little or no accelerated erosion. Notes. 1. This final classification will need constant modification in the light of trial, experience, and application. The present suggestion is tentative only. 2. In part the Roman numerals represent a summary of their accompanying long and short fractions, but the entire complex—physical and cultural—must be considered and appraised carefully in all pertinent, observable respects before final field judgment is made. Complete Specimen Notation. 5 1 D-E 1 1 2 6 5 2— 2 1 3 1 3 2 3 II   — Photographic mosaics might prove more serviceable than the topographic maps, and are essential, of course, for those areas not as yet covered by the new topographic sheets. They could be printed on a scale greater than that of the One-inch Topographic Map (i.e., greater than 1: 63,360), and they provide a variety of information not shown on the maps. In addition to aerial mosaics and map sheets (properly indexed so that they can be filed and recorded), clinometers, soil augers and cars complete the field equipment. Field procedure runs, in outline, as follows. Essentially homogeneous unit areas are recognised tentatively from the base data (on maps and photographs) or as a result of the investigator's prior acquaintance with the region. The boundaries of these tentative units are sketched on the mosaic and an experimental characterisation of the unit is made and recorded on the mosaic in the form of a long fraction. Outdoors, the boundaries are checked and corrected at every point to which access is possible, and the final, representative long fraction is recorded. Lastly, judgments of the three summary classifications are made. In the office, the pencilled notations on the field sheets are inked in, the mosaics are checked for omissions and inconsistencies, and border notations are co-ordinated with adjacent sheets.

One great advantage, especially, where urgency is given to land survey is that field personnel needs little training: it must be interested in the work, fully acquainted with the notation and skilled in the use of vertical aerial photographs. Field workers need be but few in number, although it is essential that they have the broadest possible outlook and training. In New Zealand adaptable men might be drawn from the Soil Survey Division and Plant Research Bureau of the Department of Scientific and Industrial Research and possibly from the Departments of Agriculture, Forestry and Lands and the honours geography school at Canterbury College. In parties of two, it is estimated that, under the variety of New Zealand geographic conditions, they could cover from 40–140 square miles a day. The Contributions of the Method. In New Zealand the results yielded by a nation-wide stocktaking undertaken on the unit area method would be of real value to a number of different agencies, both public and private. The data mapped would contribute materially to the solution of specific problems (soil erosion, noxious weeds), to rehabilitation and developmental programmes, to national and local administration (public works, taxation, catchment boards, etc.) and to manufacturing and commercial enterprises (stock and station agencies, commercial banks, dairy companies, etc.). From the completed maps and mosaics information of limited and specific kind can be readily abstracted. There are few Government departments which could not utilise the results of such a survey to the great advantage of the Dominion. Only a selection of these many possible contributions can be touched on here. Three of the more outstanding of current domestic problems are to expand primary production, to rehabilitate returned servicemen and to counteract the growing menace of soil wastage. The unit area method of land classification contributes directly to their solution. It discovers and appraises the conditions under which accelerated erosion occurs and indicates its distribution. It measures the amount, quality and location of land which should be retired. It indicates, at the same time, the extent and distribution of areas suited to pioneer development, to resettlement and to closer occupance. It reveals where education, government assistance and demonstration might most readily expand production. Its results touch few Departments of State more closely than the Department of Works, especially since that department is now responsible for the operation of the Soil Conservation and Rivers Control Act (1941). By indicating (more rapidly than any other survey method) the nature and extent of the soil erosion problem, the precise location of critical problem areas, the significance of many related and underlying factors, it furnishes the broad factual base on which an effective programme of soil conservation must be founded. The data provided indicate further those areas which, from the point of view of possible siltation as a result of rampant erosion, are unsuitable for the location of reservoirs or hydro-electric power sites; or again it reveals those areas in which erosion control must be inaugurated to protect existing dams from early siltation. The method may lend material aid in planning roading and railway projects. It

should help the State Forest Service to locate its inevitably enlarged planting programmes; the Education Department in planning school renewals or new buildings; the Land and Income Tax Department in more soundly apportioning taxes in rural communities, and the Department of Industries and Commerce in designing the location of new rural industries. On a wider plane, the classification of land by the unit area method would indicate broadly, though with greater accuracy than hitherto, the population absorptive capacity of the Dominion's farm, station, and forest land. Most important, by recording the physical capabilities of land, it indicates where changing culture techniques might be most suitably and efficiently applied, so as to enable New Zealand's soil to contribute permanently and in the largest possible measure to the world's food supplies. Conclusion: The Geographic Approach. The unit area method of land classification employs an essentially geographic approach to land problems, for it focuses attention on the area or region as a unit of investigation and embraces a very wide group of phenomena—physical and cultural—in their association within the areal complex. Many scientific disciplines and technical agencies are concerned with land use and land planning. The former include economics, sociology, history, political science, botany, zoology and pedology; the latter include agencies dealing with specific and relatively narrow forms of land use such as agriculture, forestry, public works and town planning. There is in this situation a serious problem of integration and co-ordination, and an obvious danger of difficulties arising in land planning through narrowness of view and bias towards particular uses. Such was the experience in the United States under the variety of New Deal projects, and criticism of similar order can be fairly levelled against the small-scale land use survey and land planning projects undertaken in recent years in New Zealand. If, however, it is appreciated that planning consists largely of an investigation of the trends in land use within definite units of area and in directing these trends (rather than imposing some preconceived and possibly biassed pattern of use), the scientific basis of planning thus becomes the study of areas and of all the critical facts and relationships within them; and this requires the broadest possible approach. It is here that the geographic method and approach are of value. For a considerable period of time American, British, and continental geographers have been working on and experimenting with methods of regional land inventory (Joerg, 1935; Stamp, 1943). The present method of land survey and classification, though it may seem unique and novel to other specialist disciplines, is the outcome of a long series of experiments with techniques designed by geographers to facilitate land inventory. The unit area method provides a quantitative portrayal of the occupance pattern and is complete in areal coverage. In permitting, at the same time, a speed of operation not previously attained, considerable detail, and a high degree of accuracy, it contributes both to geography and to the multiplicity of the practical requirements of land planning.

Literature Cited in the Text. Bennett, H. H., 1943. More Food With Soil Conservation. Soil Conservation, vol. viii, no. 8, pp. 171–176. Connell, R. P., Kidson, E., et al., 1939. Land Utilization Report of the Heretaunga Plains. N.Z. Dept. Sci. and Industr. Res. Bull., No. 70. Cumberland, K. B., 1941. A Century's Change: Natural to Cultural Vegetation in New Zealand. Geogr. Rev., vol. xxxi, no. 4, pp. 529–554, and Pl. II, facing p. 554. —– 1943. A Geographic Approach to Soil Erosion in New Zealand. Austr. Geographer, vol. iv, no. 5, pp. 120–131. Hilgendorf, F. W., 1935. The Grasslands of the South Island of New Zealand: An Ecological Survey. N.Z. Dept. Sci. and Industr. Res. Bull., No. 47. Hudson, G. D., 1936. The Unit Area Method of Land Classification, Ann. Assoc. Amer. Geographers, vol. xxvi, no. 2, pp. 99–112. Joerg, W. L. G., 1935. Geography and National Land Planning. Geogr. Rev., vol. xxv, no. 2, pp. 177–208. Jones, W. D. and Finch, V. C., 1925. Detailed Field Mapping of an Agricultural Area. Ann. Assoc. Amer. Geographers, vol xv, no 3, pp. 148–157. Madden, A. E., 1940. The Grasslands of the North Island of New Zealand. N.Z. Dept. Sci. and Industr. Res. Bull., No. 79. Stamp, L. D., 1943. Land Utilisation in Britain, 1937–1943. Geogr. Rev., vol. xxxiii, no. 4, pp. 523–544. Taylor, N. H., 1938. Land Deterioration in the Heavier Rain Districts of New Zealand. N.Z. Journ. Sci. and Technol., vol. xlix, no. 2, pp. 657–681. —– et al., 1939. Maintenance of Vegetative Cover in New Zealand, with Special Reference to Land Erosion. N.Z. Dept. Sci. and Industr. Res. Bull., No. 77.