Soil fertility and plant nutrition

Modern vegetable growers want to operate in an environmentally sound way, but how can vegetables be grown with minimal losses to the environment? Answers are first required to basic questions: What is soil fertility and what role do plant nutrients play in vegetable production? What are typical amounts and forms of plant nutrients in soils? What nutrient forms do crops take up? What are the input and output of plant nutrients to and from soils? What factors affect conversion between forms? What variations in plant nutrient availability occur between soils? To optimize plant nutrition, it is necessary to ask: Which plant processes are particularly sensitive to plant nutrients? How do nutrients move within the plant? How do plant nutrients affect growth, yield and quality of the produce? What will be the crop’s nutrient requirement throughout the growing season? What will be the total requirement of the crop for nutrients? What is the expected trend of nutrient concentration in the different organs during the growing season? Decision-making in fertilization strategy requires answers to other specific questions: When is soil and plant nutrient status considered sufficient? What are the critical values or ranges for plant nutrients? What type of soil and plant analyses are best for making fertilizer recommendations? What will be the supply of nutrients from the soil? What are the natural and man-supplied sources of plant nutrients? Which principles of plant nutrient management does the grower need to understand and apply to ensure unrestricted crop growth, product quality and minimum environmental pollution? How effective will any application of manure and fertilizer be and, therefore, how much should be applied?