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Characterization of Corn Nitrogen Status with a Greenness Index under Different Availability of Sulfur
Author(s) -
Pagani Agustín,
Echeverría Hernán E.,
Andrade Fernando H.,
Sainz Rozas Hernán R.
Publication year - 2009
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/agronj2008.0136
Subject(s) - nitrogen , leaf area index , crop , yield (engineering) , agronomy , dry matter , zea mays , grain yield , sulfur , human fertilization , index (typography) , crop yield , nutrient , zoology , chemistry , mathematics , biology , materials science , metallurgy , organic chemistry , world wide web , computer science
Several methodologies measure leaf greenness intensity and relate it to crop N status. There is no evidence, however, of the utility of this variable to detect N deficiencies in corn ( Zea mays L.) under S deficiency. The objective of this work was to evaluate the potential of two indexes based on leaf greenness intensity to detect N deficiencies in corn under different levels of S. Two experiments at Balcarce, Argentina (Bce I and Bce II), and one at 9 de Julio, Argentina (9dJ), were conducted during the 2005–2006 and 2006–2007 seasons with different levels of N and S. Weekly measurements of greenness index (GI) were performed, and whole‐plant samples were taken at four developmental stages to determine crop N and S accumulation. No N × S interaction was found in any measured variable. Nitrogen increased dry matter N and S accumulation, grain yield, and GI. Sulfur fertilization resulted in increased S accumulation in all experiments, and grain yield at Bce II and 9dJ. This nutrient also increased GI during several crop stages in all experiments. A nitrogen sufficiency index (NSI) was related to its relative yield ( R 2 : 0.67, 0.63, 0.43, 0.67 for stages V5–V8, V9–V11, V13–V14, and V15–V18, respectively) under different S levels. On the other hand, a new index called relative greenness index (RGI), proposed for situations that could present S deficiencies, was also related to its relative yield ( R 2 : 0.67, 0.81, 0.63, 0.82 for stages V5–V8, V9–V11, V13–V14, and V15–V18, respectively) under different S levels. The regression lines of both indexes were coincident for all sample dates. It was concluded that crop N status can be characterized under different levels of S through the NSI. Future research, however, should test these results under a wider range of S levels.