Fertiliser Deficiencies - Papers describing deficiency symptom in crops and field vegetables.

Soil Fertilizers - Information with regard to soil pH, fertilizers and lime application.

Agriculture-Fertilizers - Details about different fertilizers and their applications in agriculture.

Soil Quality Institute - Research findings and practical technologies that help conserve and improve soil conditions. Applicable to farming, ranching, forestry and gardening.

Soil Fertility Guide - Common fertilizers and their characteristics.

Sugar Cane Production and Soil Fertility. - Information on the relationship between the quality of sugarcane and soil fertility.

Soil Fertility - Answers questions related to the enhancement and maintenance of soil fertility.

Fertilizer Zone - An introduction to fertilizer use.

Managing Fertilizers on a Small Farm - Information on soil testing and fertilization for small farms.

Fertilizers, Soil fertility, Plant Nutrition - Information on all aspects of soil fertility and fertilizers.

Soil Fertility Research - Information about university research.

How to Apply Fertilizer to Wheat - Application time, forms of fertilizer and methods of application to be considered when applying fertilizer to wheat.

Department of Soil Management and Soil Fertility - Information regarding the many aspects of chemical soil fertility.

Soil Fertility Implications - Describes the different fertilization requirements for direct seeding.

Soil test interpretations - Gives examples of soil test values and explains their significance.

NPK Plant Nutrient Models - Online programs that simulate the response of crops to fertilization, crop residue incorporation and consider the effects of time, soil type, cultural practice and weather. Downloads available for researchers.

PEERS Lessons about soil - Educational site about soil analysis giving general information about pH, organics, color and other important soil fertility criteria.

Chloride Crop Nutrition - Essential nutrient for plant growth. Testing for deficiencies and effects on plant growth. Effect on plant diseases.

What is Soil Fertility - Information about soil fertility and how it can be improved.

The International Fertiliser Society - Scientific, technical, environmental, economic and safety aspects of the production, marketing, use and application of fertilizers.

Getting Back to Basics - Crop information for all US regions and information on soil fertility and fertilizer application.

European Fertilizer Manufacturers Association - Contains details about plant nutrient requirements, recommendations for fertilizer use and best agricultural practices for fertilizer application.

International Fertilizer Industry Association - Describes the production, distribution and consumption of fertilizers, their intermediates and raw materials

International Fertilizer Development Center - Production and agronomic effectiveness of fertilizers.

European Network for Field Vegetable Crops - Environmental problems associated with the nitrogen fertilization of field grown vegetables.

Fertiliser Manufacturers Research Association - Aims to promote and encourage responsible fertilizer use. Contains many fertilizer fact sheets.

Soil Characterization - Simple step by step guide to soil sampling and analysis with explanatory images.

Potentially beneficial effects from liming - A university lecture describing the physical and chemical effects of liming on different soil types.

Fertilizer and Lime Research Center, New Zealand - Agricultural use and the environmental impact of fertilizer, lime and soil amendments.

Field Museum - Educational site for students and teachers about soil and soil biology.

Efficient Fertilizer Use Manual - Comprehensive online book about proper fertilizer uses, soil pH and soil sampling.

Introduction to Soils - Lectures about soil surveys, soil texture, soil acidity and soil fertility. Information about liming, fertilization and soil testing with particular reference to forestry.

Introductory Soil Science - Lectures and Laboratory Units of the Soil Sciences Courses at the University of Minnesota. Influences on soil fertility are explained and simple soil tests are described.

Technical Information - A detailed description of the influence of soil cation exchange capacity, soil pH, base saturation and alkalinity.

Fertilizer Industry Federation of Australia - Provides publications and educational material.

Potassium In Agriculture - The influence of potassium on plant nutrition and soil.

Preplant Soil Nitrate Tests - Description of tests that allow farmers to adjust nitrogen applications to meet the needs of each specific field.

Rebuilding Lost Soil Fertility - Measures to improve soils suited to farmers in the third world.

Plant Nutrition and Soil Fertility Laboratory - Institute of the University in Denmark. Features publications and research reports.

Foliar Fertilizer - Introduction to the sources of, and the uses of foliar fertilizer.

Phosphorus fertilizers - Describes the effective use of this fertilizer. Soil availability, fertilizer characteristics and application.

Food and Fertilizer Technology Centre - Technical information and practical experiences about agricultural food production and the use of fertilizers.

Soil Fertility Management - Frequently asked questions about soil fertility, the application of animal wastes, organic and chemical fertilizers. Also features an online discussion forum.

Soil acidity and liming - A factsheet describing the negative effects of soil pH and how to counter them.

Soil Fertility & Crop Nutrition - A list of factsheet, infosheets and publications available for download or for ordering. These give details about fertilization of different crops, soil management and soil improvement.

Soil Fertility Guide - Soil fertility practices in Manitoba and general fertilizer use considerations. Details about fertilizers, their characteristics, application rates and usage recommendations. N-fixation, Manure and soil factors are also described.

Iron Chlorosis - Explains how to detect and combat iron deficiency in plants.

Soybean Soil Fertility - Information and discussion on nutrient uptake and yield response to P and K. Recommendations for P and K and some examples of yield response to these nutrients.

Fertilizer and Lime - An overview of various long-term and short-term P and K trials with corn and soybean.

Secondary and Micronutrients for Vegetables and Field Plants - A series of reports describing the effects of various micronutrients on the growth and health of plants. Pictures of plants with deficiency symptoms.

Micronutrient Disorders, HYG-1252-98 - On the deficiencies that may occur in soilless floriculture, and how these can be remedied.

Manures and Fertilizers - Indian Agricultural Resources. Information about manures, organic, inorganic and biofertilizers.

Soils and Soil Management - Offers a database and search function of a range of articles about fertilizers, micronutrients and fertilizer application.

Nutrient management of field crops - A good introduction into the basics of fertilization and soil analysis. It describes the soil and plant processes, macro- and micronutirents and different fertilizer types and their use. Explains the basics of soil sampling and analysis.

Understand your soil test: Sulfur - Background information on the role of sulphur in soil fertility, sulphur containing fertilizers and explanation of the results of a soil test.

Recommended soil testing procedures - Describes important soil tests and explains how to perform and interpret them.

Nitrogen fertilizer materials for field crops - The role of nitrogen in soil and plants. Explains the nitrogen content and form in common fertilizers.

Phosphorus and potassium - Describes the phosphorus (P)and potassium (K) soil testing and fertilizer recommendation system in Ontario, Canada.

Fertilizer Use and Crop Production - This site has information on soil testing, fertilizer recommendations, micronutrients, plant tissue analysis, organic soils, calculation of fertilizer rates and manure.

The acidity of forest soils - A student paper describing soil conditions in forests. Particularly what causes the pH to change and what influences this will have on the ecosystem.