Abstract

Foliar sprays with micronutrients are widely employed in agricultural production as an alternative to improve soil fertilization and plant nutritional status. We hypothesized that less water-soluble sources of manganese (Mn; MnCO₃) could serve as a slow-release source compared to a water-soluble source (MnSO₄.H₂O). Our goal here was to evaluate Mn-sources (MnSO₄.H₂O and MnCO₃) and rates (150; 250; 350; and 450 g ha⁻¹) sprayed in the 3^rd and 4^th trifoliate leaflets of soybean growing in clayey and sandy soil under controled conditions. In phenological stages V7 (vegetative period) and R1 (reproductive period), dry matter, height, the diameter of the stem, and Mn-content in the shoot, stem, and in the trifoliate leaflets were determined. Results showed that the application of Mn resulted in an augmented Mn-content in the 3^rd and 4^th trifoliate leaflets (sandy) and the 3^rd and 5^th trifoliate (clayey). The MnSO₄.H₂O promoted Mn-retranslocation from the 3^rd/4^th trifoliate to the stem and the 5^th/6^th trifoliate. However, MnCO₃ was accumulated in the 3^rd/4^th trifoliate. The Mn-rates presented a linear response in sandy soil and quadratic response in clayey soil. Clayey soil was characterized by the higher Mn-contents in the stem, while sandy soil presented the higher Mn-contents in the 3^rd, 4^th, 5^th, and 6^th trifoliate. Our results suggest that MnSO₄.H₂O is more effective in increasing Mn-content in soybean leaves during plant development due to the Mn-retranslocation to sink organs (5^th/6^th trifoliate leaflets and shoot).

摘要

含有微量营养素的叶面喷洒广泛用于农业生产，作为改善土壤施肥和植物营养状况的替代方法。我们假设与水溶性来源 (MnSO ₄ .H ₂ O)相比，水溶性较差的锰来源 (Mn; MnCO ₃ ) 可用作缓释来源。我们的目标是评估在第 3^次和^第4^次喷洒的Mn 源（MnSO ₄ .H ₂ O 和 MnCO ₃）和比率（150；250；350；和 450 g ha ^-1）在受控条件下在粘土和沙质土壤中生长的大豆的三叶小叶。在物候阶段 V7（营养期）和 R1（繁殖期），干物质、高度、茎的直径和枝条、茎和三叶小叶中的锰含量被确定。结果表明，Mn的应用导致了3增强Mn含量^次和4^个枳小叶（沙）和3^次和5^次枳（粘质）。所述的MnSO ₄ ·H ₂ ö从促进锰retranslocation 3^次/ 4^个枳到杆和5^个/ 6^个枳。然而，锰₃积累在第 3^次/^第4^次三叶中。Mn 比率在砂质土壤中呈线性响应，在粘土中呈二次响应。粘质土壤的特点是在茎高锰含量，而砂土在3呈现的更高的Mn-内容^RD，4^日，5^日及6^日枳。我们的结果表明，MnSO ₄ .H ₂ O 在植物发育过程中更有效地增加大豆叶片中的 Mn 含量，这是由于 Mn 重新转移到汇器官（^第5^次/^第6^次三叶小叶和枝条）。