Nitrate Leaching Potential under Variable and Uniform Nitrogen Fertilizer Management in Irrigated Potato Systems

Abstract

<jats:p>Potato (<jats:italic>Solanum tuberosum</jats:italic>) production in Washington State's Central Columbia Plateau faces nitrogen (N) management challenges due to the combination of coarse textured soils (sandy loam to loam) and hilly topography in this region as well as the high N requirement of potato. Potato growth and development can vary with the N availability across the field. In this 2-year study, two adjacent potato fields were selected each year (1999 and 2000). Each field was soil sampled on a 200 × 200 ft (61.0 m) grid to establish existing soil N content. One field was preplant fertilized with variable N rate while the other was conventionally preplant fertilized, applying a uniform rate across the field based on the field average. During the growing season, each field was monitored for nitrate leaching potential using ion exchange membrane technology. Soil and plant nutrient status were also monitored by collecting in-season petiole and soil samples at two key phenological stages, tuber initiation and tuber bulking. Overall this research showed that variable rate preplant N fertilizer management reduced N leaching potential during the early part of the growing season, but did not persist the entire season. Since preplant N accounted for only 40% of the total seasonal N applied, it is possible that further gains could be made with variable rate in-season N application or with variable rate water application.</jats:p>

Yield response of potatoes to variable nitrogen management by landform element and in relation to petiole nitrogen – A case study

“…There are few published reports for variable management of potatoes in landform-based management zones. Whitley and Davenport (2003) found that variable management of N fertilizer in potatoes based on spatial variability of soil organic matter reduced N leaching potential during the early part of the growing season, though this effect did not persist during the entire growing season. Cambouris et al (2008) assessed variable management based on two management zones, for rate and timing of N fertilizer application on potato tuber yield, distribution and specific gravity.…”

Strategies to Reduce Nitrate Leaching into Groundwater in Potato Grown in Sandy Soils: Case Study from North Central USA

“…Therefore, it is critical to manage N using site specific nutrient management (SSNM) system, which accounts for spatial soil variability within the fields and makes precise recommendation of N need that increases efficiency of applied N (Khosla et al 2002;Cambouris et al 2008). Site-specific N management has reduced NO 3 leaching on areas with high leaching potential on loamy fine sandy soil of Washington, indicating SSNM's potential to improve N management in potato cropping system (Whitley et al 2001). This can be done either by dividing fields into management zones which differ in term of soil properties, landscape position, and yield potential or using optical methods to assess spatial variation in crop and soil N status.…”

“…These measures of "real-time" crop N status can be linked directly to variable rate fertilizer N applicators, which can immediately translate the measurements into fertilizer rates, and tailor N management to the precise need of the crop for a specific field at real time. Variable fertilizer N application method can reduce N loss (Whitley and Davenport 2003). This practice is common in Europe for cereal crops (Zillmann et al 2006;Jorgensen and Jorgensen 2007), but has not been fully developed for potatoes.…”

Evaluation of Modified Variable Rate Granular Fertilizer Spreader for Spot-Specific Fertilization in Wild Blueberry Fields

“…After delineation of management zones relationships between spatial variation in soil/crop parameters and yield can be examined (Pilesjö et al, 2005). Positive results were found by researchers after dividing the fields into management zones depending on topographic features and other soil variation in different cropping systems (Thrikawala et al, 1999;Whitley and Davenport, 2003;Goddard and Grant, 2001).…”