Booker Agriculture International (BAI) is engaged on agricultural Consultancy assignments and land management contracts in the tropics and subtropics. This manual brings together the accumulated expertise of the BAI Land Resources Service to provide a valuable and readable summary of soil-related methods and terminology.
Part 1 Introduction: aims and scope of the manual; selection of contents; layout of the manual; the need for soil surveys. Part 2 Types of land resource field studies: exploratory surveys; reconnaissance surveys; semi-detailed surveys; detailed surveys; the role of land resource surveys in integrated projects; limitations of land resource surveys. Part 3 Survey organization and practice: terms of reference; background data; survey logistics and planning; general guidelines for survey planning; survey techniques; data recording; soil sampling; field laboratories. Part 4 Classification and mapping of soils: soil classification; soil mapping units. Part 5 Land Evaluation: land suitability classification; land capability classification; field evaluation of agronomic potential; productivity indices or ratings. Part 6 Soil physics: background to soil physical measurements; infiltration; hydraulic conductivity; bulk density; soil porosity; soil-water relations; soil particle density; soil structure, strength and consistency; soil texture and particle size distribution. Part 7 Soil chemistry: problems in interpretation of soil chemical measurements; variability f of soil analytical results; summary of soil chemical data interpretation; soil reaction (pH); cation-exchange capacity; individual exchangeable cations; phosphorus; nitrogen; organic carbon; free carbonate; gypsum; sulphur; micronutrients; trace elements - chronium, cobalt, iodine, nickel, selenium and silicon. Part 8 Soil and water salinity and sodicity: electrical conductivity; sodium measurements; definitions of saline and sodic soils; salinity and sodicity of irrigation water; soluble salts - saturation extract; leaching requirement; soil classification and salinity/sodicity. Part 9 Soil and land suitability reports and maps: the purpose and use of soil and land suitability reports; quality of soil and land suitability reports; writing soil and land suitability reports; soil and land suitability maps.