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Soil‐ and Plant‐Based Indices in Potato Production in Response to Polymer‐Coated Urea
Author(s) -
Cambouris Athy.,
St. Luce Mervin,
Ziadi Noura,
Zebarth Bernie J.
Publication year - 2014
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj14.0041
Subject(s) - loam , petiole (insect anatomy) , agronomy , chemistry , sowing , growing season , nitrate , water content , horticulture , soil water , environmental science , botany , biology , soil science , hymenoptera , geotechnical engineering , organic chemistry , engineering
Polymer‐coated urea (PCU) is used in potato ( Solanum tuberosum L.) production to maintain or improve tuber yield while minimizing N losses, but the mode of N release is different from conventional soluble N sources. Hence, it is not known how soil‐ and plant‐based indices of N availability would perform in response to PCU application. A 3‐yr study was conducted on a sandy‐loam soil in Quebec, Canada, to examine the effect of PCU application rate (0, 60, 120, 200, and 280 kg N ha −1 ) on petiole NO 3 –N concentrations, chlorophyll meter readings (SPAD readings), soil mineral N content, and total tuber yield. Nitrate availability throughout the growing season was monitored by measuring NO 3 adsorbed by anion exchange membranes (NO 3AEM ). The NO 3AEM values, petiole NO 3 –N concentrations, SPAD readings, soil mineral N content, and total tuber yield increased with PCU application rate. The NO 3AEM values fluctuated during the growing season due to plant N uptake and variations in soil moisture content. Using all the PCU rates across years, we found that relative yield was better related to petiole NO 3 –N concentrations measured at 45 to 50 d after planting (DAP) ( R 2 = 0.95) and to cumulative NO 3AEM values measured up to 49 DAP ( R 2 = 0.91) than soil mineral N ( R 2 = 0.67), soil NO 3 –N ( R 2 = 0.65), and SPAD readings ( R 2 = 0.53) measured at 45 to 50 DAP, respectively. This study showed that soil‐ and plant‐based indices of N availability can be used as early indicators of yield response in potato fertilized with PCU.