Phosphorus-induced zinc deficiency in wheat pot-grown on noncalcareous and calcareous soils of different properties

Abstract

The contents in carbonate-free clay-, silt-and sand-sized particle contents of the samples were determined with the pipette method after dispersion in sodium hexametaphosphate of decarbonated samples obtained by treating intact soil with a ~0.5 M HCl solution until production of CO 2 ceased. pH was determined by potentiometric measurement in a 1:2.5 w/v soil:water suspension; cation exchange capacity by extraction with 1 mol/L NH 4 OAc buffered at pH 7; exchangeable cations by atomic absorption (Ca and Mg) or flame emission spectrophotometry (Na and K); total CaCO 3 equivalent by weight loss following treatment with 6 mol/L HCl (van Wesemael 1955); active lime (i.e., 0.1 M ammonium oxalate-reactive carbonate, denoted by ACCE) according to Loeppert and Suarez (1996); electrical conductivity (EC) in a 1:5 soil:water suspension with a conductivity meter; organic C (OC) by rapid dichromate oxidation; citrate/bicarbonate/dithionite-extractable Fe (Fe d ) according to Mehra and Jackson (1960), except that extraction was performed at 298 K for 16 h; and oxalateextractable Fe (Fe ox ) according to Schwertmann (1962). Iron in the citrate/bicarbonate/dithionite and oxalate extracts was determined with the ophenanthroline colorimetric method (Olson and Ellis 1982).Olsen P was determined according to Olsen et al. (1954). For the determination of P in the 0.01 M CaCl 2 extract (CaCl 2 -P, which is a proxy for the concentration of P in the soil solution), the suspension (1:10 w:v soil:solution; 2 g of soil and 20 mL of extractant in a polyethylene flask) was horizontally shaken at 25 ± 1 ºC at 2.5 Hz for 30 min and then centrifuged at ~8 × 10 3 m s -2 for 10 min. Next, a 2 mL portion of supernatant was placed in an Eppendorf tube and centrifuged at 1.2 × 10 5 m s -2 for 15 min to remove particles with a density of 2.5 kg dm -3 and an equivalent diameter > 0.05 µm from the solution. Extraction was done in triplicate. Dissolved reactive P in all extracts was determined with the Molybdate Blue method (Murphy and Riley 1962).Zn DTPA was determined by suspending 10 g of soil in 20 mL of extractant at 25 ºC in 50 mL polyethylene tubes that were shaken at 180 rpm in a reciprocating shaker and then centrifuged at 10 4 m s -2 for 15 min (Lindsay and Norvell 1978). Zinc in the DTPA extracts was analysed using atomic absorption spectrophotometry.

Soil Nutrients Effects on the Performance of Durum Wheat Inoculated with Entomopathogenic Fungi

“…The twelve soils used in this study were obtained from the collection of 47 topsoil (0-25 cm) samples characterized by Sacristán et al (2019) [24] (see Table 1 and Table S1 in the Supplementary material). The selection of these soils was done based on several criteria: The soils were representative of the Mediterranean region, varied widely in their properties, covered a broad range of P content and were all Zn-poor soils, which resulted in an uneven P/Zn ratio.…”

“…Significant (p < 0.05) differences are marked with an asterisk, Figure S3: Nature of soil × fungal treatment interaction in K and Na uptake by plants on soils pertaining to the GSGYI < 15 (those where grain yield was increased by less than 15%) inoculated with B. bassiana (A and B) or M. brunneum (C and D). Significant (p < 0.05) differences are marked with an asterisk, Figure S4: Nutrient availability of Control (white circles) against B. bassiana (black circles) treatment for Fe (A) and Cu (C) and against M. brunneum treatment (black squares) (B and D; respectively) in soils before (x-axis) and after (y-axis) cropping, Table S1: Additional soil properties ‡ of the soils described in Sacristán et al (2019) [24], Table S2: One-way ANOVA or Kruskal-Wallis test and comparison of means ‡ for wheat biomass, nutrient uptake and grain nutrient concentration (mean value, n = 18) on the different soils at harvest, Table S3: Factorial ANOVA (soil × fungal treatment) and Kruskall-Wallis test ( † , when data failed to fulfill the criteria for parametric analysis) for grain yield, straw and nutrient uptake of durum wheat plants grown on GSGYI < 15. § Significant differences (p < 0.05) are in boldface.…”

“…Available soil P was determined following Olsen et al (1954) [26] and measured by the method of Murphy and Riley (1962) [27]. A more detailed description of this procedure can be found in Sacristán et al (2019) and in the Supplementary material.…”

Optimum Olsen Phosphorus/ZincDTPA ratio for the initial growth of maize in agricultural soils of the Mediterranean region

“…negative impacts on water quality 1 . In addition, due to the relatively low nutrient uptake by crops in productive systems, 2 generous fertilization practices lead to soil nutrient imbalances and the consequent reduced absorption and antagonistic relationships between nutrients 3 …”

“…Nevertheless, the Olsen test 21 for P and the diethylenetriaminepentaacetic acid‐extractable Zn (Zn DTPA ) test for Zn 22 have proven to be useful in studies dealing with the response of crops to the soil P and Zn levels 23–27 . Thus, Sacristán et al 3 . showed that the Olsen P and Zn DTPA levels as well as the Olsen P/Zn DTPA ratio were good predictors of the yield and nutrient content of durum wheat pot‐grown at different levels of P and Zn application.…”