I I I. Miscellaneous Soils Paper No: 2 GENERAL LAND CAPABILITY MAP OF JAMAICA. N.H. Batjes. (October 1986) MINISTRY OF AGRICULTURE

Transcription

1 I Miscellaneous Soils Paper No: 2 GENERAL LAND CAPABILITY MAP OF JAMAICA N.H. Batjes (October 1986) I I I MINISTRY OF AGRICULTURE Rural Physical Planning Division Jamaica Soi1 Survey Project

2 ISRIC LIBRAHY ê m. -y w<l^ Wao«nlnoen, The Motherlando Table o-f Contents 1 GENERAL 1 2 LAND CAPABILITY_CLASSES 1 3 THE_MAP ~ 2 4 QQNQL.LJDING_REMARKS 3 REFERENCES 4 Scanned from original by ISRIC - World Soil Inmation, as ICSU World Data Centre Soils. The purpose is to make a safe depository endangered documents and to make the accrued inmation available consultation, following Fair Use Guidelines. Every eft is taken to respect Copyright of the materials in the archives where the identification of the Copyright holder is clear and, where feasible, to contact the originators. For questions please contact soil.isric@wur.nl indicating the item reference number concerned. XII15

3 1 GENERAL The exploratory soi 1 map o-f Jamaica (Batjes, 1985) gives inmation about Jamaica's soi Is and their occurrence in the landscape. With additional knowledge o-f the cl imate (IICA, 1983) and land use, this soi1 map can be used to delineate zones si mi 1 ar general capabilities - agriculture. The resulting land capability map should be used the explicit understanding that, because o-f the general isation which is inherent to the 1:500,000 scale, there will be many smal 1 areas of di-f-ferent capabilities which cannot be shown. The grouping of land into broad capability classes is useful educational purposes (e.g. National Atlas) and determining the country's available acreage intensive ms of land use. The General Capability Map is not, however, suited specific land use recommendations which purpose a Computerized Evaluation System is being developed at the Rural Physical Planning Division of the Ministry of Agriculture, Jamaica (sëe.batjes, Bouwman & Sinclair, 1986). Section 2 defines the broad land capability classes and their subratings which are based on the type of major limitations intensive land use. A short description of the land corresponding to each identified capability subclass is presented in Section 3. Concluding remarks are made in Section 4. 2 LAND CAPABILITY CLASSES The land capability classification used this map is a modification of the system which has been used in thé Soil and Use Surveys of Jamaica (R.R.C., ). Seven categories of capability classes, which are indicated Roman numerals, are shown on the map, some of which are divided into subclasses. This division is indicated by smal 1 suffix letters and based on the main limiting factors. The land capability classes define broad categories of use: - I cultivation (til lage) almost no 1i mitati ons

4 - II -For cultivation (til lage) moderate 1imitations. - III - cultivation (til lage) strong 1imitations. - IV tree crops, pasture and very limited cultivation. - V not cultivation, but tree crops and planted est. - VI not cultivation, but poor est. - VII little or no productive use. Taking into account the level of generalization, four subclasses are considered, viz.: 'e' if the principal limiting factor is steepness of slope or erosion hazard; *c* if it is the climate, that is a combination of low annual rainfall, high potential evapotranspiration, and a growing season shorter than 60 consecutive days; 'f' if it is the shallowness and rockiness of the soi1; "w* if it is poor natural drainage or excess water caused by regular flooding. 3 THE MAP Cl_ass_X land is level or nearly level (O to 5 percent slopes) deep, freely drained, medium textured soiis which have high natural fertility and good water retention characteristics. Simple management practices, 1ike a well balanced erop rotation appropriate field maintenance, are required to sustain optimum yields. Class I land is very limited in extent and distribution and mainly found as small areas along the south eastern and northern coast. is rated as Cl_ass_Ij[ when the 1 imi tations only moderately reduce the overall suitability cultivation (tillage). This type of land requires moderate management practices to permit sustained good yields. Class lic land is al most level and occurs in an area a very unfavourable rainfall distribution. Under adequate irrigation, it would be rated as Class I land. Class Uwe land shows moderate 1imitations tillage which are mainly due to unfavourable internal drainage and the risk of erosion because of rolling slopes (8 to 16 percent). It also has moderate fertility and the soi1 is slightly acid. Class II land covers small parts of the country and includes interior valleys in udic areas (Uwe) and areas of recent alluvial soils in the - 2 -

5 dry southern plains (lic). The Cl.ass_I_.IIcw capability class comprises o-f gently undulating land (O to 5 percent slope) which shows strong limitations - cultivation due to poor natural drainage, poor workability (mainly cracking clay soils) and dry climate. This type of land requires drainage works and irrigation to be made cultivation. The St. Catherine, Cl arendon and Westmorel and Plains are the major areas of Class IIIcw land, but minor areas of this subclass occur along the northern coast. The areas that are designated as C_ass IV contain a mixture of land which is mainly pasture and commercial tree crops only smal1 areas suited intensive cultivation. The main limiting factors are steepness of slope (generally 16 to 30 percent) ensuing susceptibility to erosion, and localized shallowness and rockiness of the soils. Class IVes land is very extensive throughout the island and especially in the central part. C_ass_V land occurs mainly in the north western part of Jamaica in hilly and mountainous areas (slopes over 30 percent) where the soils are predominantly shallow, rocky and highly susceptible to erosion. This category of land can support tree crops and planted est if appropriate erosion control is exercised. Cultivation is not recommended this type of land. identified as C_ass_VI_, is not intensive ms of agriculture due to very unfavourable soi 1, slope or climate conditions and should theree be left in its natural state. In selected areas it is moderately tree crops and planted est but this always requires extensive erosion control. Class VI land is extensive in the upper levels of the Blue Mountain Range (Vies), some of the limestone hills in south and central Jamaica (Vies), and in the heavily karstified cockpit country. Shallowness, rockiness and droughtiness, or low foothold and swampiness, or strong salinity and regular flooding precludes most agricultural uses on C_ass_V_I_ land. This type of land vncompasses the big morasses of St. Elizabeth, that can only be made cultivation after major drainage works, smaller swamps in the eastern and western extermities of the island, tidal swamps and flats, and big areas of rock outcrops and shallow soils. 4 CONCLUDING REMARKS The attached map shows the general capability of the land in - 3 -

6 Jamaica agriculture. The legend is adapted -from the Capability System developed by R.R.C. ( ), which de-fines generalized categories o-f land use like arable land, pasture and estry. The importance of making speci-fic land use proposals, however, is evident. Consequently, it is necessary to rate each mapping unit respect to a range o-f crops. Hence, the develcpment of a Computerized Evaluation System Jamaica at the Rural Physical Planning Division o-f the Ministry o-f Agriculture. REFERENCES BATJES, N.H. (1985) Exploratory soil map of Jamaica (1:500,000). Rural Physical Planning Unit, Central Region, Ministry of Agriculture, Jamaica. BATJES, N.H., A.F. BOUWMAN & K.M. SINCLAIR (1986) Jamaica Physical Evaluation System (JAMPLES). Technical Soils Bulletin No 3, Jamaica Soil Survey Project, Rural Physical Planning Division, Ministry of Agriculture, Jamaica. IICA (1983) Agro-climatic study of Jamaica. Inter American Institute Cooperation on Agriculture/ORSTOM, San José, Costa Rica. R.R.C. ( ) Soil and Use Surveys, Jamaica. The Regional Research Centre, Soil Research and Survey Section, University of the West Indies, Trinidad. ENCL0SURE: General Capability Map of Jamaica (1:500,000) - 4 -

7 n^ïo SC A L E LAND CAPABILITY I : 500, 000 MAP OF JAMAICA 77^30'E 78?00'E MINISTRY OF AQRICULTURE RURAL PHYSICAL PLANNING SOIL SURVEY UNIT. DIV. "7ë 30'E 77P00E C A R i B B E A N S E A I8 30N. I8 30'N IVc Lucea»/v" IVcs/VII Port Antonio I8 00'N I8 00'N- C A R I B B E A N SE A 77?30'E 78?00'E LAND CAPABILITY CLASSES cultivation (Tillage) almost no cultivation (Tillage) moderate est limitations» I cultivation cultivation (Tillage) Tree crops, pasture strong and not and tree cultivation, crops. but planted limitations. C~~ III 76, 30'E limitations very limited l V ' not cultivation, but I est VII little or no productive KEY TO e Slope MAIN w Poor s Shallowness C Climatic natural LIMITING FACTORS drainage poor and 4 rockiness use. Icm* Scale THE factors (Irrigation required ) = 25 km* MINISTRY OF AQRICULTURE RURAL PHYSICAL PLANNING DIVISION SOIL SURVEY PROJECT HOPE KINGSTON 6 l 500, TATUTE 10 KILOMETERS MILES Ref : N.H BATJES Int Comm. (86/10) R. P. P D / J SS.P Cartogropher E.Edwards l5n 22>30