Interpretation of soil phosphorus availability by Mehlich-3 in soils with contrasting phosphorus buffering capacity

Abstract

Increasingly rational use of phosphate fertilizers by agriculture is important, especially in Brazil, due to its importance for global food security and its high dependence on phosphate fertilizers for crop production. Thus, correlation and calibration researches with soil available phosphorus (P) extractants to improve the recommendation and the use of P are extremely important. Our objectives were (i) to determine soil P recovery rates and critical levels by the extractants Mehlich-1 (M1), Mehlich-3 (M3), and Ion Exchange Resin (RTI); (ii) to adjust predictive models of P recovery rates and critical levels for each extractant, as a function of soil properties related to the soil P buffer capacity, and (iii) to adjust the an interpretation table of soil P availability by M3 taking into account soil P buffer capacity indices. A pot experiment under greenhouse condition was conducted, in which the treatments were generated by the combination of a factorial 12 × 6, being 12 soil samples collected at a layer of 0.00-0.20 m, and six doses of P. The experimental units were constituted by plastic pots with capacity for 2.0 dm³ of soil, in which four hybrid corn plants (Zea mays L.) were cultivated for 45 d. The experimental design was a randomized complete block with four replicates. After cultivation, soil samples were collected from each experimental unit, and the determination of soil available P was performed by the extractants. The remaining P and the clay content were the soil properties that best correlated with the P recovery rates and P critical levels in the soil by the M1 and M3. The IER did not show sensitivity to soil P buffer capacity. The M3 had a discontinuous loss of extraction capacity with increasing soil P buffer capacity. Therefore, it is recommended the use of M3 as P extractant in soils with different characteristics, but a measure of soil P buffer capacity such as remaining P or clay content have to be used.

Refining phosphorus fertilizer recommendations based on buffering capacity of soils from southern Brazil

“…The trP_M1 is an indicator of the P adsorption capacity. Its increase due to the higher clay content was expected and is supported in the literature (Rogeri et al, 2016;Reis et al, 2020). Clayey soils tend to have higher Fe and Al contents, elements directly linked to the P adsorption (Bortoluzzi et al, 2015).…”

“…Thus, clayey soils have a higher P adsorption capacity (Rheinheimer et al, 2003;Oliveira et al, 2014), with both variables being strongly correlated (data not shown). In the same sense, P-rem is an indicative of the soil's adsorption capacity, in which lower values represent a greater soil sorption potential (Rogeri et al, 2016;Reis et al, 2020). The positive correlation of tr 1 P_M1 with potential CEC and TOC can be indirect (Eberhardt et al, 2008).…”

“…Phosphorus has a high affinity for soil particles, causing low availability to plants and low recovery fertilizer efficiency (Barrow and Debnath, 2018;Zhang et al, 2018). The clay content and mineralogical soil composition have a decisive influence on the retention of P and its availability (Eberhardt et al, 2008;Fink et al, 2016;Rogeri et al, 2016;Reis et al, 2020). Besides, parameters such as pH and organic matter can also affect the P dynamics in the soil (Almeida et al, 2003;Fink et al, 2016), as well as changes in the environment (Bortoluzzi et al, 2015).…”

“…In soils with insufficient P availability, the addition of phosphate fertilizers improves the nutrient use efficiency (Cubilla et al, 2007;Rubio et al, 2008;Reis et al, 2020). The saturation of the adsorption sites with the highest binding energy (Rheinheimer et al, 2003;Oliveira et al, 2014), and the increase in the number of negative electrical charges (Barrow, 2015), reduce the P adsorption, allowing a greater percentual of P available to plants ( Barrow and Debnath, 2018;Boitt et al, 2018;Zhang et al, 2018;Thuy et al, 2020).…”

Bone Char: Synthesis, Characterization, and Agronomic Application as an Alternative Source of Phosphorus

“…There are three sharp peaks at 2θ = 7.47, 22.90, and 24.04, which are characteristic of the crystal structure of calcium hydrogen phosphate hydrate Ca(H 2 PO 4 ) 2 (JCDPS 9-347). The presence of hydroxyapatite (Ca 5 (PO 4 ) 3 OH (JCDPS [24][25][26][27][28][29][30][31][32][33] elements (Figure 4d and Table 1).…”