The Soils Bulletin sets out guidelines for quality management in soils and plant laboratories for the use of heads and staff of laboratories aiming at improving performance. The Bulletin introduces a number of basic measures to be adopted in a laboratory regarding, among other, standard operating procedures (protocols), organization and personnel, facilities and safety, equipment and working materials, analytical or testing systems and basic statistical tools, quality control and reporting and filing of results. It emphasizes the change in attitude and practices of all laboratory personnel for quality assurance and control without substantial additional cost. These guidelines are based on the principles of Good Laboratory Practice discussed in various relevant document such as ISO, ISO/IEC Guides, ISO 9000, OECD and CEN documents, national standards and a number of textbooks. Contents: Chapter 1: Introduction, (1) What is Quality?, (2) Quality Management (3) Quality Assurance, (4) Quality Control, (5) Good Laboratory Practice (GLP), Chapter 2: Standard Operating Procedures, (1) Definition, (2) Initiating a SOP, (3) Preparation of SOPs, (4) Administration, Distribution, Implementation, (5) Laboratory Notebook, (6) Relativization as Encouragement, Chapter 3: Organization and Personnel, (1) Function and Aims of the Institute, (2) Scope of the Laboratory, (3) Organigram, (4) Description of Processes, (5) Job Descriptions, Personnel Records, Job Allocation, Replacement of Staff, (6) Education and Training of Staff, (7) Introduction of New Staff, Chapter 4: Facilities and Safety, (1) Housing Facilities, (2) Safety, (3) Admittance to the Laboratory, Chapter 5: Materials: Apparatus, Reagents, Samples, (1) Introduction, (2) Apparatus, (3) Reagents, (4) Samples, Chapter 6: Basic Statistical Tools, (1) Introduction, (2) Definitions, (3) Basic Statistics, (4) Statistical Tests, Chapter 7: Quality of Analytical Procedures, (1) Introduction, (2) Calibration Graphs, (3) Blanks and Detection Limit, (4) Types of Sample Material, (5) Validation of Own Procedures, (6) Drafting an Analytical Procedure, (7) Research Plan, Chapter 8: Internal Quality and Control of Data, (1) Introduction, (2) Rounding and Significant Figures, (3) Control Charts, (4) Preparation of a Control Sample, (5) Complaints, (6) Trouble-Shooting, (7) LIMS, Chapter 9: External Quality Control of Data, (1) Introduction, (2) Check Analysis by Another Laboratory, (3) Interlaboratory Sample and Data Exchange Programmes, (4) Trouble-Shooting, (5) Organization of Interlaboratory Test Programmes, (6) Quality Audit.