Effects of nitrogen and sulfur application on grain yield, nutrient accumulation, and harvest indexes in maize

Abstract

Nitrogen (N) and sulfur (S) are crucial nutrients in maize production. However, N and S application effects on accumulation and partitioning of both nutrients are not well documented for variable-yielding maize. The objective of this work was to evaluate the effect of N and S fertilization on grain yield, dry mater (DM), N, and S accumulation and harvest indexes of maize growing under no tillage in different environments. Two experiments at Balcarce, Argentina (Bce I and Bce II) and two at 9 de Julio, Argentina (9dJ I and 9dJ II), were conducted during the seasons of 2005–06 (Bce I), 2006–07 (Bce II and 9dJ I), and 2007–08 (9dJ II) under different levels of N and S. The measured variables were grain yield, DM, N, and S accumulation, as well as DM, N, and S harvest indexes (DMHI, NHI, and SHI). In general, no N × S interaction was determined in any measured variable. Nitrogen fertilization increased grain yield (P < 0.01), DM (P < 0.05), N (P < 0.05), and S (P < 0.05) accumulation in all experiments. Interestingly, N fertilization increased S accumulation either in treatments with or without S fertilization. Even though the effect of S fertilization on these variables was less pronounced, this nutrient increased grain yield in three of the four experiments (Bce II, 9dJ I, and 9dJ II, P < 0.05). Relative S accumulation rate was lower than relative N accumulation rate, indicating that it would be possible to delay S application compared to N fertilization. Dry mater and nutrient harvest indexes increments in response to N and S fertilization were not stable through sites and years. In general, NHI was higher (12% on average) than SHI. Maize grain yield was strongly and linearly associated with N and S uptake regardless of the fertilization treatment. Nitrogen and S accumulation were closely and linearly associated as well. It would be convenient, however, to confirm these results in environments with a wider range of S levels in the soil.