Contrasting changes of soil pH between urea and ammonium sulfate are reflected by the growth and nutrient status of Sorghum bicolor (L.) Moench in an alkaline saline-sodic soil: a greenhouse assessment.

Santa Fe

Encuentro; XXXIII Argentinian Meeting of Plant Physiology (RAFV2021); 2021

Sociedad Argentina de Fisiología Vegetal

Alkaline saline-sodic (ASS) soils are restrictive for agriculture activity worldwide. In these soils, nitrogen fertilization can be used strategically. Ammonium sulfate (AS) and urea (U) fertilizers are widely used for crop production, differing in their effect on soil pH. Therefore, the aim of this work was to evaluate the changes in the rhizosphere pH and growth parameters of sorghum after the application of these two nitrogen fertilizers under greenhouse. For this trial, three sorghum hybrids, named here 163, 155 and SIP, were sown in 3L pots filled with two soil types: an alkaline saline-sodic (pH 9.14. and EC 4.68 µS/cm) and no-saline-sodic soil (pH o 5.69 and EC 0.73 µS/cm). U and AS (120 kg ha N-1) were applied in two times (a half at sowing and the rest at the V5 stage). The rhizosphere pH, shoot dry weight, OJIP parameters, and leaf cations concentration were measured at the end of the trial (38 days after sowing). The results showed that, unlike U, the AS fertilization decreased rhizosphere pH (~0.6 units) and, depending on the hybrid, the shoot dry weight increased from 150% to 300% as well as the foliar concentrations of K+ (14% - 112%), Mg2+ (55% - 252%) and Ca2+ (81% - 253%) with respects to the no-fertilized treatments. Moreover, AS-fertilized plants showed higher PIabs and Fv/Fm values under AAS soil. We thus conclude that, the application of AS improves the sorghum nutrition and growth in AAS soil, representing a promising tool for sorghum production under saline-alkaline soils.