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Subirrigation as an Innovative New Technology to Reduce Water Consumption f

CIG Projects in PIA | Pacific Islands Area NRCS
 CIG Projects in the Pacific Islands Area:


Subirrigation as an Innovative New Technology to Reduce Water Consumption for Native Plant Nursery Production

Grantee: Purdue University

Abstract
The purpose of this demonstration project is to introduce a scientifically-proven irrigation technology known as subirrigation into native plant nursery production for forest restoration programs in Hawaii. This technology has been shown to greatly reduce irrigation water consumption because water is recycled in a closed-system instead of being released as runoff. We will establish subirrigation demonstration at three nurseries using three native forest tree species. Seedlings produced using this technology will then be planted into demonstration field plots.

Forest restoration projects in Hawaii commonly involve planting of forest tree seedlings produced in native plant nurseries to help facilitate rehabilitation of grazed areas that were formerly forest. These nurseries generally rely upon overhead irrigation to produce seedlings, which result in poor water use efficiency because of the broad foliar canopies that develop in many of these native species. Fertilizer nutrients are also leached from these overhead irrigation systems, which may cause environmental contamination. Additionally, overhead irrigation may result in uneven distribution of water into individual container cells, thereby creating high variability in plant quality. Subirrigation, whereby plants are watered from beneath container cells, is a scientifically proven technical innovation that offers an alternative to traditional overhead irrigation systems. Using subirrigation, irrigation water is maintained within a closed system in which water is pumped from reservoir tank to an application tank. Through the action of capillary rise, water then saturates the media in plant container cells and drains back to the reservoir tank for reuse in subsequent irrigations. Because the system is closed, no leaching of water or fertilizer nutrients occurs. Additionally, research has shown that plant quality can be improved significantly due to better uniformity of irrigation.

The specific objectives of this project are:

  • Demonstrate the efficiency of water conservation and reduced nutrient leaching using subirrigation compared to overhead irrigation in production of native plants for restoration.
  • Show the benefit of subirrigation in producing plants of equal or better quality to those produced through current overhead irrigation.
  • Exhibit the beneficial field performance of plants produced through subirrigation through demonstration field plantings.