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Soil and Plant Tests to Optimize Fertilizer Nitrogen Management of Potatoes.

Ziadi, N., B.J. Zebarth, G. Belanger and A.N. Cambouris. 2012. Springer Netherlands

Abstract

Appropriate fertilizer nitrogen (N) management can optimize tuber yield and quality, and reduce the risk of environmental N losses. However, the optimal fertilizer N management can vary among fields and years. Plant- and soil-based tests are examined in this chapter as diagnostic tools to improve fertilizer N management in rain-fed potato production in eastern Canada. Plant-based diagnostic tests assess potato N sufficiency and can be used to guide in-season fertilizer N management. The nitrogen nutrition index (NNI) based on whole plants, the petiole nitrate concentration, and the leaf chlorophyll meter reading (SPAD) have been shown to successfully diagnose the level of potato N nutrition during the growing season in eastern Canada. The use of gene expression, a promising tool for a direct measurement of potato N sufficiency compared with chemical or optical methods, is also examined. Soil-based tests can be used to provide an estimate of soil N supply to adjust the at-planting fertilizer N rate. The use of pre-plant and in-season soil nitrate tests, ion exchange membranes, indices of soil mineralizable N, and near-infrared reflectance spectroscopy (NIRS) are examined. A combination of a soil-based test to guide at-planting fertilizer N application and a plant-based test to guide in-season N management may be most effective.