Water and Nutrient Management In Protected Agriculture - the Importance of Managing Water

There are many factors that influence nutrient availability which will be discussed in this workshop, including morphological differences in nutrient uptake, differing strategies to apply nutrients and maximize uptake, including substrate management and innovations that have been made in fertilizer technology.  Since almost all intensive horticultural operations use porous, lightweight soilless substrates, and more importantly most protected agriculture uses some form of irrigation, precision water management has been cited as the key factor to optimize nutrient management in these environments. Soilless substrates have negligible anion exchange capacity and thus soluble nitrate and phosphate can be easily leached from the root zone.  From a practical standpoint, it is important that we monitor the interception efficiency and leaching fraction of irrigation applications, in order to optimize the nutrient availability.  We now have the ability to monitor soil and substrate moisture in real-time using precision sensor technology, which will allow us to better relate matric potential measurements to actual plant water use.  The use of these tools will allow growers to make better decisions in the future to decrease the cost of production, reduce environmental impacts and increase the quality of crops grown in protected culture.