Contrasting Effects of Phosphorus and Potassium Deficiencies on Leaf Area Development in Maize

SALVAGIOTTI, FERNANDO; GUTIÉRREZ-BOEM, FLAVIO HERNÁN; USANDIVARAS, LUIS MARÍA ARIAS

CROP SCIENCE

CROP SCIENCE SOC AMER

Año: 2018 vol. 58

0011-183X

Management of P and K in agricultural systemsis similar, since both move mainly by diffusionin soil. In maize (Zea mays L.), radiation captureis a consequence primarily of leaf area forma-tion and senescence, but little is known about Pand K interaction in determining both variables.The objective of this study was to assess theeffects of P, K, and P  ́ K interaction on (i) leafappearance rate and final leaf number, (ii) indi-vidual leaf area, (iii) leaf senescence rate, and(iv) leaf area development in maize. Two fieldexperiments were performed in the 2011?2012and 2012?2013 growing seasons, under nowater and N limitations. Treatments consistedof different levels of P and K fertilization. Differ-ential effects of both nutrients occurred for leafarea formation and senescence. Phosphorusdeficiencies decreased average leaf appear-ance rate by 10% and individual leaf area by18%, whereas K deficiency reduction of indi-vidual leaf area was 14%. Final leaf numberdid not change under both P and K deficiency.Phosphorus deficiencies decreased leaf senes-cence rate by 2%, whereas K deficienciesaccelerated this process by 12%. As the resultof the counteracting processes of expansionand senescence, P deficiency effects on greenleaf area index were larger at the beginning ofthe crop cycle and tended to attenuate after,whereas K deficiencies were more important inlater stages. These results may help in modelingthe effects of P and K shortage in maize.