A comparison of indexes to estimate corn S uptake and S mineralization in the field

• Published in: Biology and fertility of soils Vol. 54; no. 3; pp. 349 - 362
• Main Authors: Carciochi, Walter D., Wyngaard, Nicolás, Divito, Guillermo A., Cabrera, Miguel L., Reussi Calvo, Nahuel I., Echeverría, Hernán E.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2018; Springer Nature B.V
• Subjects: Agriculture; Availability; Biomedical and Life Sciences; Climate change; Corn; Field tests; Incubation period; Life Sciences; Mathematical models; Mineralization; Organic soils; Original Paper; Plateaus; Soil; Soil Science & Conservation; Soils; Sulfur; Sulphur; Uptake; Vegetables; Apparent S mineralization; Incubations; Field trials; Sulfur balance
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/s00374-018-1266-9

The development of simple predictors of sulfur (S) mineralization and its correlation with field-derived data may help improving corn S availability diagnosis. The objectives of this study were (1) to compare methods to estimate soil S mineralization, (2) to develop a model to predict soil S mineralization from S mineralization indexes and edaphic variables, and (3) to predict field-grown corn S uptake (S
uptake
) and apparent S mineralization (S
min-app
) from different S mineralization indexes and edaphic-climatic variables. We evaluated 26 experimental sites where we measured edaphic variables as soil organic C (SOC), organic C in the particulate fraction (C-PF), S mineralization potential (S
min-10wk
), S mineralized during a short-term (7 days) aerobic incubation + initial inorganic S (S
min-7d
 + S
inorg)
, and N mineralized during a short-term (7 days) anaerobic incubation (N
an
). Additionally, 18 field experiments were carried out to quantify S
uptake
and S
min-app
. The C-PF, S
min-7d
 + S
inorg
, N
an
, and SOC were variables significantly correlated with S
min-10wk
(
r
 = 0.89, 0.89, 0.88, and 0.85, respectively). We developed a simple model to predict S
min-10wk
from selected edaphic variables (S
min-10wk
 = 0.038*N
an
 + 0.106*SOC + 0.74;
R
a
2
 = 0.87). The S
min-10wk
, C-PF, and S
min-7d
 + S
inorg
showed a liner-plateau association with S
uptake
(
R
2
 = 0.73, 0.53, and 0.48, respectively). We modified the method to estimate S
min-app
to account for S losses (S
min-app (modified)
) and developed a model to predict S
min-app (modified)
from C-PF (S
min-app (modified)
 = 4.65*C-PF + 9.86;
R
2
 = 0.62) or S
min-10wk
(S
min-app (modified)
 = 3.0*S
min-10wk
 + 7.4; R
2
 = 0.54). Our results demonstrate that S mineralization indexes can be used to predict corn S availability under field conditions.