N:P:S stoichiometry in grains and physiological attributes associated with grain yield in maize as affected by phosphorus and sulfur nutrition

SALVAGIOTTI, FERNANDO; COURETOT, LUCRECIA; GUTIÉRREZ BGUTIÉRREZ-BOEMOEM, FLAVIO HERNÁN; FERRARIS, GUSTAVO; DIGNANI, DAMIAN; FERRARIS, GUSTAVO; DIGNANI, DAMIAN; PRYSTUPA, PABLO; MAGNANO, LUCIANA; PRYSTUPA, PABLO; MAGNANO, LUCIANA; SALVAGIOTTI, FERNANDO; COURETOT, LUCRECIA; GUTIÉRREZ BGUTIÉRREZ-BOEMOEM, FLAVIO HERNÁN

FIELD CROPS RESEARCH

ELSEVIER SCIENCE BV

Año: 2017 vol. 203 p. 128 - 138

0378-4290

Balanced nutrition isnecessary to reduce yield gaps in maize.Simultaneous phosphorus (P) and sulfur (S) deficiencies may be present insoils, so a P x S interaction is expected. In maize, yield is closely relatedto grain number (GN); thus, nutrient deficiencies impacting crop growth duringGN formation can consequently impact yields. Grain nutrient concentration mayreflect soil supplying capacity, and nutrient stoichiometry in grains can beused as an indirect indicator of nutrient deficiency for a retrospectivediagnosis of sites responsive to P or S fertilization. The objectives of thisstudy were to: i) determine maize response to increasing S fertilizer rates andto P addition; ii) analyze the effects of P, S, and their interaction onmechanisms involved in yield determination of maize; and iii) evaluate theeffects of P and S shortage on stoichiometric relationships among N, P, and Scontent in maize grains. Two fertilization experiments were conductedon-farming conditions in 19 sites-year (SY) for analyzing grain yield responseto increasing S fertilizer rates (E1), and studying the interaction between Pand S fertilization on grain yield and physiological attributes associated withgrain yield determination (E2), i.e.CGRCP, IPARCP, RUECP and biomass at R6. Also N(%N), S (%S) and P (%P) concentration in grains were determined. Stoichiometricrelationships among N, P and S in both P or S fertilized and unfertilizedtreatments in all SY were analyzed. Average grain yield response due to S and Paddition was ca. 13 and 20%,respectively. Grain yield increased up to S fertilizer rates around 10 kg S ha-1.P addition increased CGRCP by 15 to 60% in 8 SY while S addition 12to 16% in 2 SY. Both, RUECP and IPARCP were positivelyassociated with biomass production. P fertilization increased IPARCPby 4%, but no S effect was observed. Before silking, P addition boostedcumulated radiation by 7%, but after silking no P or S effects were observed. Asignificant P x S interaction was observed for RUECP, since Sfertilization increased RUECP by 14% only when P was not added..Independently of P or S shortage, grain N content scaled almost isometricallywith grain S content, while N:P and P:S showed allometric relationships.Phosphorus deficiency did not modify N:S, N:P nor P:S stoichiometry. Likewise,S addition did not modify the N:P or N:S stoichiometry. A significant change inthe intercept of the P:S relationship was observed in response to fertilization and may be used as a tool foridentifying S responsive sites using grain nutrient analysis.