【作者】 崔京珍；

【导师】 朱端卫；

【作者基本信息】 华中农业大学 ， 植物营养学， 2011， 博士

【摘要】 硼是植物生长必需的微量元素之一。硼与土壤中铁氧化物之间的相互作用会对土壤微环境-植物生长产生影响,是影响硼的土壤化学行为和硼的植物营养作用的重要因素。本研究模拟土壤中硼与针铁矿的吸附反应,利用凝胶共沉淀方法,人工合成普通针铁矿和含硼针铁矿即：吸附硼针铁矿(ad-B-goethite)和包被硼针铁矿(oc-B-goethite)。将普通针铁矿和含硼针铁矿引入红壤,利用土培方式,通过设置不同处理,观察含硼针铁矿对油菜苗期和收获期长势-长相及表观生物量的影响；研究含硼针铁矿对土壤致酸离子及其它土壤性质的影响；利用同位素示踪试验研究含硼针铁矿在土壤中硼的释放特性及生物有效性。主要研究结果如下：1.包被硼针铁矿的热水溶性硼含量和全硼含量比吸附硼针铁矿高,其有效硼占全硼含量的比例比吸附硼针铁矿低；吸附硼针铁矿的硼比包被硼针铁矿的容易释放和被植物吸收利用。不同针铁矿比表面积大小顺序为：包被硼针铁矿>针铁矿>吸附硼针铁矿。含硼针铁矿表面Fe-OH-Fe的表面羟基弯曲振动的部分吸收峰在针铁矿基础上有所减弱,且吸附硼针铁矿保持了针铁矿的结构,而包被硼针铁矿结构发生变化。2.含硼针铁矿能提高油菜不同生育期地上部和根部干物质积累量,使油菜生长状况比单独施硼处理和单独施针铁矿处理好。含硼针铁矿增加油菜一级有效分枝数,提高其收获系数,但含硼针铁矿处理油菜株高和第一级有效分枝枝高降低。不同含硼针铁矿在不同的生育期对油菜的影响作用不尽相同。3.含硼针铁矿提高土壤热水溶性硼含量和土壤供硼能力,能够持续满足油菜整个生育期对硼的需求。土壤热水溶性硼含量的提高,促进油菜对硼的吸收利用,并且土壤热水溶性硼含量和油菜硼含量与油菜干物质积累密切相关,说明,土壤热水溶性硼含量的提高是油菜硼吸收量增加和生物量增加的重要原因。4.含硼针铁矿提高土壤pH值,降低土壤交换性酸含量,油菜收获期土壤pH升高比苗期明显；其效果顺序为：包被硼针铁矿>吸附硼针铁矿>针铁矿。含硼针铁矿对交换性H+影响较明显而对交换性A13+影响较小。油菜生物量表现与土壤pH值升高和交换性酸含量的降低密切相关。由此说明,含硼针铁矿处理,土壤pH值提高和交换性酸下降是油菜生长良好的又一重要原因。5.含硼针铁矿降低土壤活性铝、活性锰含量,这一效果在油菜苗期比在收获期明显。苗期土壤活性铝、收获期土壤活性锰含量的减少降低了油菜对铝、锰的吸收,苗期土壤活性铝含量与油菜铝含量,收获期土壤活性锰含量与油菜锰含量分别呈显著正相关关系。含硼针铁矿使土壤不同形态锰含量发生变化,其中植物难以利用形态锰含量增加,减少了植物对过量锰的吸收,促进植物生长。6.土壤热水溶性硼含量的增加不能降低土壤活性铝、锰含量,而植物对硼的吸收有利于抑制铝、锰的毒害作用。土壤铝、锰含量与土壤热水溶性硼含量无相关关系,而油菜铝、锰含量与油菜硼含量呈现高度负相关。含硼针铁矿降低土壤活性铝、锰含量,减少土壤铝、锰的供应能力,尤其是通过给油菜提供硼营养从而抑制铝、锰对油菜的毒害作用,促进油菜的生长。逐步回归分析说明,提高土壤pH和降低土壤交换性H+和活性Mn含量为苗期油菜生长提供了良好的土壤微环境；而收获期土壤pH和活性A1对土壤酸环境的影响比较重要。7.含硼针铁矿影响土壤不同形态磷含量,对Org-P影响最明显。土壤Al-P、Fe-P、Org-P含量与油菜吸收磷量和油菜干物质积累量高度相关。不同形态的磷对油菜不同部位磷吸收量和干物质积累量影响不同。茎秆磷含量的减少和土壤Org-P含量增加是含硼针铁矿处理油菜株高相对较低的重要原因。8.含硼针铁矿在土壤中以晶型状态存在为主,油菜苗期吸附硼针铁矿明显活化,收获期包被硼针铁矿才活化明显。苗期无定形铁、游离铁含量的增加影响土壤A1-P和EXC-Mn的含量,收获期游离铁的增加影响Al-P、Org-P的含量。无定形铁增多有利于O-Fe-P的释放,提高闭蓄态磷的有效性,同时对OM-Mn、RO-Mn含量产生影响。含硼针铁矿的活化对土壤磷、锰形态产生影响,而不会影响含硼针铁矿中硼的解吸,油菜对铁的吸收利用也未出现不利影响。9.含硼针铁矿能提高油菜苗期土壤中不同形态活性有机质的含量；高活性有机质与土壤热水溶性硼含量呈显著相关,并影响油菜对硼的吸收利用。有机质对土壤不同磷形态的影响主要是高活性有机质和低活性有机质对A1-P和Org-P的影响。低活性和中活性有机质是影响土壤不同形态锰含量的主要成分。10.含硼针铁矿提高油菜苗期土壤中有效钙、镁含量；在此条件下,油菜根部对铜、锌吸收量增加,地上部对铜、锌吸收量减少；逐步回归分析说明,良好的土壤供硼环境和较低的活性铝、锰含量有利于油菜根系生长,而铝、钙含量的减少和镁吸收量的增加有利于油菜地上部的生长。11.有无植物参与条件下,含硼针铁处理在土壤中10B释放量都不断增加,包被硼针铁矿比吸附硼针铁矿10B释放量高。植物的参与有利于含硼针铁矿1oB的释放。苗期油菜地上部和根部生物量不断增加,油菜对10B吸收的累积量与含硼针铁矿中10B的释放量一致,即10B的释放有利于植物对硼的吸收利用。10B释放动力学方程拟合结果说明：无植物参与条件下,零级速率方程和抛物线方程对吸附硼针铁矿、一级速率方程对包被硼针铁矿10B释放量拟合度较高；有植物参与条件下,零级、一级和抛物线方程均适合描述吸附硼针铁矿和包被硼针铁矿10B释放过程,其中,一级速率方程对包被硼针铁矿10B释放过程拟合达到极显著。吸附硼针铁矿中10B的释放速度在短期内比较快,而包被硼针铁矿中10B的释放速度持续较高,这与含硼针铁矿在土壤中硼的活化特性相呼应。更多还原

【Abstract】 Boron is one of the essential trace elements for plant growth. The interaction between boron and iron oxides in soils will impact on soil micro-environment and plant growth, which also was an important factor affecting soil chemical behavior and plant nutrition of boron. In present study, the reaction of boron and goethite was simulated using gel co-precipitation method. Goethite and two types of boron-containing goethite were synthesized in laboratory:goethite which had boron either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Original goethite and boron-containing goethite were added to red soil using soil culture method. Through setting the different treatment, we observed the effect of boron-containing goethite on the growth of seedling and harvest time of rape and apparent biomass; studied the effect of boron-containing goethite on acidified ion of soil and other soil properties; studied the release characteristics and bioavailability of boron of boron-containing goethite in soil using the test of isotope. The main findings were as follows:1. The content of HWSB and total boron of oc-B-goethite were higher than that of ad-B-goethite. The proportion of available boron and total boron of that was lower than ad-B-goethite. The release and uptake for plant of boron in ad-B-goethite was easier than that in oc-B-goethite. The increase of BET of different types of oxides was in order of: oc-B-goethite>goethite>ad-B-goethite. The bands of Fe-OH-Fe in-plane bending and parts of the adsorption peak were weak compared with the original goethite. Ad-B-goethite maintained the structure of goethite, and the structure of oc-B-goethite was changed.2. Boron-containing goethite increased the dry accumulation of shoot and root of rape at different growth stages. The growth situation of rape of boron-containing goethite was better than that of boron treatment and goethite treatment. Boron-containing goethite increased the first effective number of branch and the harvesting coefficient of rape. Plant height and the first effective branch height decreased in boron-containing goethite treatment compared with other treatments. Different types of oxides at different growth stages of rape had different effect on the rape growth.3. Boron-containing goethite increased the content of HWSB and boron supply capacity of soil, which could continue to meet the needs of rape for boron at the whole growth period. The increase of HWSB content promoted the uptake of boron for rape. The content of HWSB of soil and boron content of rape are closely related with dry matter accumulation, which indicated that it was an important reason for the increase of boron uptake and rape biomass to increase the HWSB content. 4. Boron-containing goethite increased soil pH and decreased soil exchangeable acid content. Soil pH in harvest time was higher than that in rape seedling. Different types of oxides were in order of:oc-B-goethite>ad-B-goethite>goethite. Boron-containing goethite impact the exchangeable H+ more obvious than the exchangeable Al3+. The increase of soil pH and the decrease of exchangeable acid were closely related to rape biomass, indicating that the increase of soil pH and the decrease of soil exchangeable acid was another important reason for the better growth of rape.5. Boron-containing goethite decreased the content of soil active Al and Mn, and the result in rape seedling was more significant than that in harvest time. The decrease of soil active Al content in rape seedling and active Mn content in harvest time reduced the uptake of Al and Mn for rape. Soil active Al content in rape seedling was significantly positive correlated with Al content of rape and active Mn content in harvest time was significantly positive correlated with Mn content of rape. Boron-containing goethite changed the status of different forms of manganese in the soil and the content of non-active manganese for plants increased, which reduced the uptake of manganese for plant and improved the growth of plant.6. Although the increase of HWSB could not reduce the content of soil active Al and Mn, the uptake of boron for plant was favorable to inhibiting the effect of Al and Mn toxicity on rape growth. There was no correlation between the content of soil Al or Mn and HWSB content, but Al and Mn content in rape was significantly negative correlated with boron content in rape. Boron-containing goethite could decrease the content of active Al and Mn in soils, reduce the supply capacity of soil Al and Mn, especially could improve the availability of soil boron through the increase of provision of boron nutrition to inhibit the toxicity of Al and Mn, which promoted plant growth. The stepwise regression analyses indicated that the increase of soil pH and the decrease of soil exchangeable H+ and active Mn content provided a better soil micro-environment for rape seedling growth; soil pH and active Al in harvest time of rape had a more important effect on the soil acid environment.7. Boron-containing goethite impacted different forms of phosphorus content, especially for Org-P. The content of soil Al-P、Fe-P、Org-P was highly related to phosphorus uptake and dry matter accumulation of rape. The effect of different forms of phosphorus on phosphorus uptake of different parts of rape and dry matter accumulation were different. The decrease of phosphorus content of stem and the increase of soil Org-P were the important reason of height of rape decreased in boron-containing goethite treatment.8. Boron-containing goethite mainly existed in crystalline state in soils. Ad-B-goethite was favorable to active in rape seedling and oc-B-goethite was favorable to active in harvest time. The increase of Feo and Fed content of soil in rape seedling impacted Al-P and EXC-Mn content of soil. The increase of Fed content in harvest time impacted Al-P and Org-P content. The increase of Feo content benefited O-Fe-P release increasing the available of occluded phosphorus, while impacted the content of OM-Mn and RO-Mn. The activation of boron-containing goethite impacted the phosphorus and manganese forms, which would not impact the boron desorption. Uptake and utilization of Fe for rape also did not appear adversely affected.9. Boron-containing goethite could increase the content of different forms organic matter; high labile organic matter was significantly correlation with HWSB, and affected the uptake of boron for rape. The effect of soil different forms organic matter on different forms phosphorus mainly was the effect of high and low labile organic matter on Al-P and Org-P. Low and middle labile organic matter was main component for the effect of soil different forms Mn.10. Boron-containing goethite improved the available Ca and Mg content; the uptake of Cu and Zn of rape root increased and the uptake of Cu and Zn of rape shoot decreased. Stepwise regression analysis showed better soil environment for boron supply and lower active Al and Mn content was favorable to rape root growth, while decrease of Ca and Al content and increase of Mg uptake was favorable to rape shoot growth.11. Condition with plants or no plants, the amount of 10B release in boron-containing goethite treatment continued to increase; oc-B-goethite had a higher 10B release amount than ad-B-goethite. The treatments for plants was favorite to increasing the release of 10B of boron-containing goethite. Rape shoot and root biomass continued to increase, while the accumulation of 10B uptake for rape was in keep with the release of 10B of boron-containing goethite. Therefor, the release of 10B was favorable to uptake of 10B for rape. Fitting result of kinetic equations showed that in condition with no plants zero-rate equation and parabolic diffusion equation fitted the rules of 10B release in ad-B-goethite treatment better than other equations, while first order rate equation fitted the rules of 10B release in oc-B-goethite treatment better than other equations. in condition with plants, zero-order, first-order and parabolic diffusion equation fitted to describe the rules of 10B release of ad-B-goethite and oc-B-goethite in the soil. Among them, first-order equation fitting 10B release rules of oc-B-goethite was highest of all. The release rate of 10B in ad-B-goethite is faster in short term, while The release rate of 10B in oc-B-goethite is consistently higher in long term, which was correspond to the activation characteristics of boron of boron-containing goethite in soil.更多还原