Water and Nutrient Supply in Horticultural Crops Grown in Soilless Culture: Resource Efficiency in Dynamic and Intensive Systems

Abstract

The process of nutrient mineralizationMineralizationis crucial to nutrition of agricultural crops. Nitrogen is often the most critical plant nutrient and therefore this chapter focusses on mineralization of nitrogen (N) as crucial factor in N nutrition of crops. In horticulture N mineralization is often high as a result of frequent organic matter additions to soil. An in-depth knowledge of the process of N mineralization and the abiotic factors regulating it is essential in order to maximize N use efficiency and avoid unwanted losses to the environment. Therefore this chapter starts with a short description of the process of N mineralization, and then provides detail on the biotic (composition of the organic matter) and abiotic factors governing the process. The process is also treated mathematically by introducing simple empirical equations that allow making rapid estimates of N mineralization. Finally, the different types of organic materials are treated with respect to expected N availability, and the problem of synchronizing N mineralization with crop N demand is treated.