Utilization of apatite in volcanic ash using functions of plants

未风化火山灰中的磷灰石是自然生态系统和农业生态系统中的天然磷资源之一。磷灰石与土壤中活性铝、铁的反应对pH值的依赖性大于对活性铝、铁种类的依赖性。在较高的最终pH值4.5，磷灰石反应很少与活性铝和铁，而磷酸盐被吸附的活性铝和铁在低于4.5的pH值区域。在pH值高于4.5的区域，酸性Fe倾向于比活性Al吸附略多的磷酸盐。柠檬酸盐和草酸盐在此pH区域表现出比活性Al和Fe更高的磷酸盐溶解。柠檬酸盐处理后，使用扫描电子显微镜观察到粗糙的表面。从这些结果来看，具有酸性分泌物或植物根分泌物螯合有机酸性质的植物是利用火山灰中磷灰石的有希望的植物。虽然日本云仙火山火山碎屑流存款中植物有效磷含量很小，只有几十mg P2 O 5 kg-1，但细颗粒磷含量很低， ...更多信息 粗粒级有效磷含量较高，且随粗粒级粉碎而增加。这些性质与其他中性至酸性火山岩相似。在重质细砂至中砂部分中发现的富磷颗粒显示出接近磷灰石的Ca/P原子比，这些颗粒被鉴定为磷灰石。云仙火山碎屑流存款中的磷灰石颗粒以离散颗粒或包裹体形式存在于其他矿物中。有效磷的增加是由于暴露的磷灰石包裹体在其他矿物。木豆和鹰嘴豆的生长，具有螯合有机酸分泌物，几乎正常生长在山。皮纳图博火山灰施氮肥，可能由于其有效磷含量低而生长不好。荞麦在云仙火山的火山碎屑流存款中表现出较好的生长。其主要原因是施用铵肥时，其泌酸能力强。少

Apatite in unweathered volcanic ash is one of the natural phosphorus resources in the natural and agricultural ecosystems. Reactions of apatite with active Al and Fe in soil depended much on pH than the kind of active Al and Fe. At the higher final pH 4.5, apatite reacted little with active Al and Fe while phosphate was sorbed much by the active Al and Fe at the lower pH region than 4.5. Aciive Fe tended to sorb slightly more phosphate than active Al at pH region higher than 4.5. Citrate and oxalate showed higher phosphate dissolution than active Al and Fe at this pH region. Rough surface was observed using scanning electron microscope after the treatment citrate. Considering these results, plants having either acid exudation or chelating organic acid exudation properties from plant roots are promising for using apatite in volcanic ash.Although plant-available phosphate content of pyroclastic flow deposit from Unzen volcano, Japan was small as much as several tens mg P2O5 kg-1, fine pa … More rticle-size fraction showed higher available phosphate content and available phosphate level increased with pulverizing of the coarse fractions. These properties were similar to other neutral to acidic tephras. Phosphorus-rich particle found in the heavy fine to medium sand fraction showed Ca/P atomic ratio close to that of apatite and these were identified as apatite. The apatite particles occurred in the Unzen pyroclastic flow deposit as discrete particles or inclusion in other minerals. The increase in available phosphate with grinding is due to exposure of apatite inclusion in other minerals.Growth of pigeon pea and chick pea, that have chelating organic acid exudation and grew almost ordinarily in the Mt. Pinatubo volcanic ash with N fertilizers, did not grow well possibly due to its low available phosphate content.Buckwheat showed better growth in the pyroclastic flow deposit from Unzen volcano. The main reason was high acid exudation ability when it was grown with an ammonium fertilizer. Less