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Revising petiole nitrate sufficiency/deficiency guidelines for irrigated cotton in the Desert Southwest
Author(s) -
Bronson Kevin F.,
Norton E. Randall,
Silvertooth Jeffrey C.
Publication year - 2021
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.1002/saj2.20213
Subject(s) - petiole (insect anatomy) , lint , irrigation , malvaceae , agronomy , growing season , fiber crop , gossypium , environmental science , biology , horticulture , botany , hymenoptera
Petiole nitrate‐nitrogen (NO 3 –N) sampling and testing remains a popular in‐season nitrogen (N) management practice in the western United States for cotton ( Gossypium hirsutum L.). However, the present guidelines used by Arizona are greater than 35 yr old and are in need of updating. The objectives of this study were to relate in‐season petiole NO 3 levels with lint yields and N deficiencies and to revise the former critical deficiency level guidelines by growth stage. Petioles were sampled between first square and peak bloom in nine site‐years of cotton N management field trials in Maricopa and Safford, AZ, from 2014 to 2018. Irrigation type in Maricopa was overhead sprinkler irrigation (OSI) (2014–2015) and subsurface drip irrigation (SDI) (2016–2018). In Safford (2014–2017), surface irrigation (SI) was used. Petiole NO 3 in SDI was dramatically lower than with SI or OSI, mostly in the deficient range. Lower lint yields in zero‐N treatments compared with pre‐plant soil NO 3 test–based reference treatments occurred in eight site‐years (Safford 2016 crop lost to late hailstorm) and were considered N deficient. Critical petiole NO 3 –N levels from 1984 were revised downward 1 g N kg −1 because several N‐fertilized treatment means of petiole NO 3 were in that range and did not exhibit an N rate–related yield depression. Sampling cotton plants for petiole NO 3 analysis should start within 1 wk of first bloom. Petiole NO 3 dynamics and critical levels in SDI cotton required further study.