Crop Nitrogen Status Assessment Tools in a Decision Support System for Nitrogen Fertilization Management of Potato Crops

Abstract

<jats:p>A decision support system (DSS) was based on the splitting of total nitrogen (N) fertilizer application combined with in-season assessments of crop N requirements aimed to matching, at field scale, potato (<jats:italic>Solanum tuberosum)</jats:italic> total crop N requirements and mineral N supply from soil and fertilizers. After the preplanting establishment of the total N recommendation based on the predictive balance-sheet method at a specific field scale, 70% of the recommended amount was applied to the crop at planting. Subsequently, at 20–50 days after emergence (DAE) the need for supplemental N was assessed through noninvasive measurements of leaf chlorophyll concentration directly in the field. A simple conditional relationship was established to support potato growers’ decisions on the usefulness of applying the remaining 30% N. This required a crop N status (CNS) assessment in the fertilized field and within a small, untreated area (zero-N for reference). The strategy developed is economically feasible, easy to operate, and validated for several potato varieties. It also gives the grower the possibility of improving N use efficiency (NUE). Several tools to assess CNS have been investigated, or are currently being investigated, at the Walloon Agricultural Research Center in Gembloux, Belgium (CRA-W) for integration into this strategy. All the tools are evaluated for four main characteristics: measurement accuracy and precision, sensitivity to N, specificity to N, and feasibility. There are invasive or noninvasive tools. The use of a chlorophyll meter (CM) has been currently developed in the DSS. Current CRA-W research is investigating the potential of crop light reflectance as an indicator of CNS (ground-based radiometers for near remote sensing and satellite multispectral imagery for spatial remote sensing).</jats:p>

A Review of Methods for Sensing the Nitrogen Status in Plants: Advantages, Disadvantages and Recent Advances

“…A range between 80% and 100% has been used to make nitrogen recommendations, but a better understanding of the N reference plot, such as applied N source, soil characteristics and application layout is needed [3]. Unlike NSI, a decision rule was applied on potato crops [41] fertilized with 70% of recommended N in order to determine if it is necessary to apply the remaining 30%, based on readings taken from a zero-N reference plot. Another index reported in recent studies is based on a ratio between SPAD chlorophyll and Dualex polyphenolics measurements.…”

“…Merkoquant test strips can measure up to 500 mg·L −1 , whereas Reflectoquant strips are capable of measuring up to 225 mg·L −1 . Samples of plant sap can be obtained generally from any fleshy petiole [41], but a petiole could be chosen depending on the crop: from artichoke leaves that have recently matured [62], from stem bases of winter wheat or maize [63], or from the leafstalks of the fifth or the sixth external completely developed leaf in lettuce [64]. Nitrate test strips turn their two-reactive zones into a red-violet combination when exposed to nitrate contained in the sample, and that color change can be measured by a hand-held reflectometer.…”

Soil‐ and Plant‐Based Indices in Potato Production in Response to Polymer‐Coated Urea

“…Petiole NO 3 –N concentrations can be influenced by several factors including N fertilization rate (Porter and Sisson, 1991; Vitosh and Silva, 1996; Bélanger et al, 2003), soil type and N mineralization rate (Vitosh and Silva, 1996), stage of growth or days after planting (Vitosh and Silva, 1996; Bélanger et al, 2003), water availability (Stark et al, 1993), and potato cultivar (Bélanger et al, 2003). The SPAD meter is another plant‐based tool that has been used to assess the plant N status of many crops including potato (Vos and Bom, 1993; Minotti et al, 1994; Gianquinto et al, 2004; Goffart et al, 2011; Ziadi et al, 2011; Giletto and Echeverría, 2013). This is possible due to the strong correlation between chlorophyll content and leaf N concentration (Vos and Bom, 1993).…”

Advances in Research on Fertilization Management of Vegetable Crops

“…Goffart et al (2011) explored the pattern of nitrogen fertilization in the Potato crop. Thus, the fertilization strategy must be considered within this system.…”

“…There is an increasing necessity to achieve and manage detailed information on the production process (Gabriel et al 2013;Goffart et al 2011) to improve the sustainability of cropping strategies. There is an increasing necessity to achieve and manage detailed information on the production process (Gabriel et al 2013;Goffart et al 2011) to improve the sustainability of cropping strategies.…”