Effect of pH on boron adsorption in some soils of Paraná, Brazil

Abstract

Temporary B deficiency can be triggered by liming of acid soils because of increased B adsorption at higher soil pH. Plants respond directly to the activity of B in soil solution and only indirectly to B adsorbed on soil constituents. Because the range between deficient and toxic B concentration is relatively narrow, this poses difficulty in maintaining appropriate B levels in soil solution. Thus, knowledge of the chemical behavior of B in the soil is particularly important. The present study investigated the effect of soil pH on B adsorption in four soils of Paraná State, and to correlate these values with the physical and chemical properties of the soils. Surface samples were taken from a Rhodic Hapludox, Arenic Hapludalf, Arenic Hapludult, and one Typic Usthorthent. To evaluate the effect of pH on B adsorption, subsamples soil received the application of increasing rates of calcium carbonate. ), Rhodic Hapludox (17.4 mg kg -1 ), and Typic Usthorthent (7.0 mg kg -1 ). The organic matter content, clay content, and aluminum oxide content (Al2O3) were the soils properties that affecting the B adsorption on Paraná soils.

Sorption of PB and B on Soils and their Separated Clay Fractions

“…According to the highest "r 2 " values, Langmuir isotherm model seemed to be the most efficient model fitting the sorption of B on soils and clay minerals. The values obtained herein were comparable to those recorded by Steiner and Lana (2013) who found that the "a" value ranged from 0.2 to 1.7 L mg g -1 ,while the b value ranged from 0.004 to 0.049L g -1 soil. This indicates that sorption of B took place in monolayers (Tan.…”

“…It is worthy to mention that the maximum monolayer adsorption capacity ("a" values) increased with increasing the pH of the metalloid soil or clay fraction suspension from 5 to 9 by 1.3, 2.3, 1.5 and 2.5 fold for the clayey soil, calcareous soil, clay fraction separated from the non-calcareous soil, clay fraction separated from the calcareous soil, respectively. In the calcareous soil, the affinity constant seemed to decrease with increasing the pH of the suspension and this result is confirmed by the findings of Steiner and Lana (2013) who recorded that the bonding energy of the B-sorption on soils decreased with increasing the pH of the aqueous solution. On the other hand, this constant seemed to increase in both the soil and on the clay fraction separated from the calcareous soil with increasing the pH of the suspensions.…”

Boron Leaching Decreases withIncreases on Soil pH

“…In the present study, adsorption isotherms were not performed, which could show the maximum capacity of B adsorption (MCBA) by the soil. In some soils from Paraná state, Brazil, which are very similar to the soil used in the present study, MCBA is up to 50 mg kg -1 (Steiner and Lana, 2013), but in some soils from São Paulo state, however, MCBA is only 11 mg kg -1 (Alleoni and Camargo, 2000). At the highest rate applied in this study (100 mg kg -1 B), even considering that B was mixed with only 60 % of the soil volume of each column, the amount added would be larger than the MCBA, and even so, less than 30 % of the applied B was leached (Table 1).…”

“…This behavior is similar to the chemical adsorption of cations in the soil. In addition to acidity, some other soil attributes also affect the sorption of B, including mineralogical composition (Alleoni and Camargo, 2000;Azevedo et al, 2001;Soares et al, 2008), texture (Alleoni and Camargo, 2000;Saltali et al, 2005) and the organic matter content (Azevedo et al, 2001;Soares et al, 2008), with consequences on the concentration of B in the soil solution (Steiner and Lana, 2013;Szulk and Rutkowska, 2013). Thus, leaching of B is higher from sandy soils than from clayey soils, especially in regions with high average annual rainfall (Silva et al, 1995;Communar and Keren, 2006), where B may reach the subsoil within a short period of time (Silva et al, 1995).…”

Foliar application of calcium and boron improves the spike fertily and yield of wheat

“…Calcium and boron deficiency can occur in very weathered soils due to continuous cropping, soil erosion, leaching of exchangeable bases, reduction of soil organic matter, and adsorption by aluminum and iron (hydr)oxides LANA, 2013;LANA et al, 2013). Boron plays a key role in root function and low B levels reduce the plant's ability to uptake water and nutrients from the soil, which often induces a Ca deficiency (TARIQ;MOTE, 2007).…”