Studies on minor elements of Ryukyuan soils : III. Manganese content of rocks, soils and crops in Okinawa (Department of Agricultural Chemistry)

1.沖縄各地から採取した土壌サンプル73ケ所95点, 作物葉サンプルとして甘蔗, 甘藷, パインアップル, ミカン其他計87点, 又, 母岩と思われる岩石57点についてマンガン量を定量した。土壌については全マンガンの外に置換性, 易還元性マンガンの定量を行い, 植物, 土壌, 岩石のマンガンの関係について調査した。2.岩石中のMn量を見るに琉球石灰岩16ケのMn分析では40∿730ppm, 平均299.9ppmであった。又古生界石灰岩, 粘板岩, 泥灰岩ではその平均が夫々289(7ケ平均), 419(21ケ平均)391(6ケ平均)ppmであった。石灰岩質土壌に所々マンガン結核が見出されたが, 多いのは14,400ppmに達した。(Table2及び7)3.母岩, 土壌間にはサンプルについて相関は見出されなかった。例えば琉球石灰岩は粘板岩よりもMn含量が少いにも拘らず, 琉球石灰岩土壌の方がMn含量が高かった(Table7参照)。4.土壌中の3型マンガンと作物葉サンプル中のMnとの間にもパインアップルを除いては相関はなかった。5.パインアップルについてはその含量と土壌の3型マンガンとの間に何れも高い相関のあることを知った。これはパインが酸性愛好植物で似かよったpHの土壌で栽培されたことと略同じ季節に葉を採取したことによろう。又パインアップル葉中のMnのToxic Levelは700∿800ppm辺にあろうと思われた6.植物葉中のMn含量には著しい差のあることを知る。(1)甘蔗一主として第5葉を取り, 葉身と葉梢に分けて定量を行った。葉身, 葉梢を通じて2.5∿377.5ppmであった。台風の影響を受けたと思われるものを除いて見ると, 葉身のマンガン137.9ppm葉梢の平均が112.4ppmとなり, 葉身のマンガン含量が高かった。(2)甘藷は葉身, 葉柄, 蔓の3部に分けて分析したが, Mn含量が葉身, 葉柄, 蔓の順で葉身の含量高く, 平均77.7ppm, 葉柄で27.7ppm, 蔓で21.4ppmであった。(3)パインアップルは第4,5葉について分析を行ったが, 台風の被害を受けてないものは36.3∿882.5ppm, 平均453.6ppmで, 他の作物よりマンガン含量が高い。(4)ミカン葉-新梢の全葉を分析に供した。そのせいかもしれないが, マンガン量は低く2.5∿67.5ppm, 平均19.7ppmであった。(5)其他インゲン, バンジロ, 茶葉, ソウシジュ, 山東菜, 大根, 高梁葉中のマンガン析を行った。7.文献Reviewを兼ねて作物マンガンと土壌マンガンについて論議を試みた。8.最後にToxic LevelとDeficient Levelを文献に徴して表記した(Table 10)。1) The total manganese content of soils samples, mother rocks, and plant leaves grown on the field sampled were determined. Besides the above, exchangeable and easily reducible manganese of soils were also analyzed. The sample number of soils, rocks, and plant were 95,87 and 57,respectively. The findings on those manganese amounts are contained in Table 2∿9. In Table 1,several properties soil samples used were subjected. 2) With regards to manganes of rocks, Ryukyu limestone had a range of 40∿730ppm in total manganese and 299.9ppm in average. Paleozic limestone, shale, and marl have 289ppm (mean of 7 samples), 419ppm (21 samples), and 391ppm (6 samples) in average amount of manganese, respectively. Manganese concretions which contained high manganese were found in many Ryukyu limestone soils. The highest total manganese content of concretion was 14,400ppm (see Table 2 and 7) 3) No correlation between rock and soil manganese was found. For instance, although Ryukyu limestone contained less manganese than Paleozoic shale, soils derived from the former are richer in manganese than soils derived from the the latter (see Table 7). 4) There was no cor elation between each three types of soil manganese and leaf manganese content except pineapple plant. 5) Correlations between pineapple leaf manganese, exchangeable, easily reducible, and total manganese of soil were all highly significant. This fact may due to that the pineapple plant is acid-soil crop and the sample leaves were taken in almost same season. It has been estimeated that the toxic level of pineapple leaf manganese may be exist around 700∿800ppm from data.6) It has been shown that a wide range of manganese content exist among various crops (see Table 8). (1) Sugarcane No.5 leaves were taken for samples and divided to two parts of leaf blade and sheath, and analysed. Amounts of blade and sheath manganese excluded samples hitted by typhoon were 139.9ppm and 112.4ppm in average, respectively, i. e. blade manganese content was higher than sheath (see Table 8-1). Typhoon damaged leaves were low in manganese content having 2.5ppm in the lowest. (2) Sweet potato Leaf blades, petioles. and veins were analyzed for manganese. Manganese content of blade, petiol, and vein were 77.7ppm, 27.7ppm, and 21.4ppm in average, repectively (Table 8-2). (3) Pineapple plant No.4 and 5 leaves of pineapple plant were used for manganese determination. Manganese mean value of pineapple leaves except damaged by typhoon was 453.6ppm which was ranked the highest among the tested crops. Damaged leaves by typhoon were so low content in manganese that the lowest was 2.5ppm (Table 8-3). (4) Citrus trees Whole leaves of new twigs were used for manganese analysis. Citrus leaf manganese content was very low and range and mean values of manganese were 2.5∿67.5ppm and 19.7ppm, respectively (Table 8-4). (5) Few other crop leaf samples, i. e. field bean, guava, tea, Acacia confusa, Santosai, and radish leaves were analyzed for manganese (Table 8-5). 7) Review of literature was tried and discussed crop leaf and soil manganese. 8) At last, toxic level and deficient level of manganese for crops were tabulated as Table 10 from literatures