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The aims of this work are to test whether boron (B) may alleviate soil acidification and aluminum (Al) phytotoxicity to rape (Brassica napus L.) in acidic soil. The Al hydroxide that reacted with borax was called ad-B-Al hydroxide. Point of zero charge (PZC) of Al hydroxide (pH 4.86) was greater than that of ad-B-Al hydroxide (pH 4.68). Compared with the control, ad-B-Al hydroxide raised the soil pH significantly by 0.10 pH units. Rape was planted in the control soil, the soil treated with Al hydroxide, and the soil treated with ad-B-Al hydroxide. It was found that the B content of the soil and rape seedlings grown on the soil treated with ad-B-Al hydroxide was greater than the others. Biomass production of rape seedlings grown in the soil treated with ad-B-Al hydroxide was significantly increased compared to that in the others. These demonstrated that ad-B-Al hydroxide can be an important source of B for plants and alleviate acidity of acidic soils because it can decrease exchangeable acid and Al toxicity in soil significantly. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine plant availability of boron (B) and relaxation of soil acid to rape seedling exhibited by B-doped goethite in acidic soil. For this purpose, two kinds of B-doped goethite were synthesized: one was goethite with adsorbed B prepared by reacting goethite with borax solution, and the other was goethite with occluded B by synthesizing goethite in the presence of boric acid. The reaction process in soil-like natural minerals of the B-doped goethite was simulated in a rhizobox culture system. Results showed that the B-doped goethite can provide available B for rape growth. Its addition on acidic soil can alleviate soil acidification by increasing soil pH and decreasing soil exchangeable acid. The observation that nutrient uptake was improved supports the view that the B-doped goethite improved soil quality, as also proved by the increase of root morphology and dry weight. [ABSTRACT FROM AUTHOR]