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The purpose of the study was to determine the effect of boron (B)-permeated goethite on soil B fractionation and the availability of this B fraction to rape seedlings (Brassica napusL.). For this purpose, goethite and two kinds of B-permeated goethite were synthesized and their processes in soil were simulated. Plant availability of B adsorbed or occluded on goethite was investigated with rape seedling. Results found that both ad-B-goethite and oc-B-goethite significantly increased the water soluble B (WS-B), specifically adsorbed B (SPA-B), B occluded in amorphous iron (Fe) and aluminum (A1) oxides (AMO-B) and crystalline Fe and Al oxides (CRO-B) content in the soil, compared with ordinary goethite. Also the B-permeated goethites improved B content of the rape seedling and therefore enhanced the rape shoot and root dry weight. Correlation analysis demonstrated that water soluble B (WS-B) plays the most important role in rape B uptake and accumulation, moreover the specifically adsorbed B (SPA-B), nonspecifically adsorbed B (NSA-B), amorphous Fe and A1 oxides (AMO-B) was also significant correlated with the B content or B accumulation of the rape. [ABSTRACT FROM AUTHOR]

Rape (Brassica napus L.) seedling pot experiments were performed with a red soil treated with goethite which had boron (B) either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Soil acidity, different forms of manganese in the soils and different elements content of the rape seedlings were determined. It was found that the addition of boron-containing goethite to the soils resulted in increased rape growth, elevated soil pH and decreased exchangeable acidity. Compared with the control, boron-containing goethite elevated the content of exchangeable manganese (Mn) (EXC-Mn), organic matter bound Mn (OM-Mn), reducible oxide Mn (RO-Mn) and residual Mn (RES-Mn) which were difficult to use for plant. Low labile organic matter was significantly correlated with easily reducible oxide Mn (ERO-Mn) (P < 0.01) and RO-Mn (P < 0.05). Middle organic matter and soil pH was significantly (P < 0.05) correlated with RES-Mn. Stepwise regression was used to select the combination of variables that best estimates shoot and root dry weight of rape seedling. Among them, soil pH, EXC-Mn, OM-Mn, RO-Mn and RES-Mn significantly influenced the dry weight of rape seedlings. The addition of boron-containing goethite improved the uptake of iron (Fe), calcium (Ca), magnesium (Mg), and copper (Cu) element and decreased the uptake of Mn and zinc (Zn) element in rape seedling. The results suggested that boron-containing goethite could provide a better soil acidity environment for plant growth; it was also an important agent increasing a part of manganese difficult to use for plant and reducing the activity of soil manganese, which was beneficial to altering rape seedling growth. [ABSTRACT FROM PUBLISHER]

Abstract: The objective of this study was to test the availability of the boron from doped oxides to rape (Brassica napus L.), and the effect of the boron doped oxides on soil acidosis. The soil was treated with goethite, manganite and their boron-containing oxides including iron oxide with adsorbed boron (i.e. ad-B-goethite), iron oxide with occluded boron (i.e. oc-B-goethite), manganese oxide with adsorbed boron (i.e. ad-B-manganite) and manganese oxide with occluded boron (i.e. oc-B-manganite). It was found that the boron content of the soil treated with boron-containing oxides was higher than those in ordinary oxide treatments and in control. Rape seedlings grown on the soil treated with boron-containing oxides took up more boron than seedlings grown on ordinary oxide treatments and the control. There was a significant relationship between boron content in oxides, soil boron content and boron total uptake of the rape. The boron-containing oxides appeared to increase the plant available boron of the soil and therefore promoted boron uptake by the rape. This demonstrated that boron desorbed from oxides used in this study can be an important source of boron for plants in acidic soils. The two kinds of boron-containing oxides were found to be more effective in addressing soil acidosis by increasing soil pH and decreasing soil exchangeable acid than the oxide which was not doped boron. This was especially so for boron-containing manganite. The introduction of the oxides also enhanced soil available nutrient content and promoted rape seedling uptake of nutrients, and therefore promoted the rape growth. Regression analysis of nutrient content of the soil and rape seedling dry weight showed there was a significant positive correlation between the Ca and Mg content of the soil and rape seedling dry weight. Multiple regression results showed only Ca content in the soil significantly influenced rape seedling dry weight. It is surmised that the boron containing oxides provided a pre-condition for the absorption of nutrients, i.e., an environment for plants to better utilize Ca and other elements during seedling growth and therefore promoted rape seedling dry weight. [Copyright &y& Elsevier]