Assessment of Soil Zn Availability for Khao Dok Mali 105 Rice: a Case study in Thailand     

Sukyankij  Saychol  Thanachit  Suphicha  Anusontpornperm  Somchai  Kheoruenromne  Irb 《Journal of Crop Science and Biotechnology》2020,23(2):181-190

Journal of Crop Science and Biotechnology - Khao Dok Mali (KDML) 105 rice is one of the most popular fragrant rice in the world with very high demand in world market. There have been a number of...  相似文献   

The forms and availability to plants of soil potassium as related to mineralogy for upland Oxisols and Ultisols from Thailand     

Timtong Darunsontaya  Anchalee Suddhiprakarn  Irb Kheoruenromne  Nattaporn Prakongkep  Robert J. Gilkes 《Geoderma》2012

Potassium (K) deficiency is widespread in crops on highly weathered upland soils under a tropical monsoonal climate. Critical assessment of the forms of K in soils and of the ability of soils to release K for plant uptake is important for the proper management of K in crop production. The relationships between different pools of K were investigated as a function of silt and clay mineralogy for 14 upland Oxisols and 26 upland Ultisols soils from Thailand. Most soils contained no K-minerals in the silt fraction. XRD showed that kaolinite is the dominant clay mineral with variously minor or moderate amounts of illite, hydroxy-Al interlayered vermiculite and smectite present in some soils. For some soils, both conventional and synchrotron XRD were unable to detect illite. Analytical TEM including EFTEM of individual clay crystals showed that clay in the apparently illite-free samples contained very small amounts of illite. Many kaolinite particles appear to contain K which may be present in illite interleaved with kaolinite crystals. A glasshouse K-depletion experiment was conducted to assess the K supply capacity and changes in chemical forms of K and K-minerals using exhaustive K depletion by Guinea grass (Panicum maximum). Potassium deficiency symptoms and mortality of plants occurred on light textured soils, whereas plants survived for six harvests for Oxisols with clay texture, relatively high CEC and higher NH₄OAc-K (exchangeable K plus water-soluble K). There is a strong linear relationship of unit slope between NH₄OAc-K and cumulative K uptake by plants indicating that NH₄OAc-K is a major form of K available to plants. Thus K-bearing minerals contributed little K to plants over the time scale of the experiment and XRD patterns of whole soil samples, silt and clay from soils after cropping mostly showed no change from those for the initial soil. An exception was for a single surface soil clay where a minor amount of smectite was formed from illite by K release to plants.  相似文献   

An evaluation of three Thai phosphate rocks for agronomic use based upon their chemical and mineralogical properties     

Chanida Charanworapan  Irb Kheoruenromne  Wanpen Wiriyakitnateekul  Robert J. Gilkes 《Soil Science and Plant Nutrition》2013,59(4):522-534

Ratchaburi phosphate rock (Rat-PR), Kanchanaburi-PR (Kan-PR), and Roi-Et-PR (Roi-PR) from Thailand, and North Carolina-PR (NCR-PR), were evaluated in the laboratory for agronomic use. NCR-PR consisted mostly of apatite (unit-cell a-value 9.336 Å, c-value 6.889 Å). Rat-PR contained apatite (a-value 9.428 Å and c-value 6.882 Å) and calcite as the main minerals. Kan-PR consisted mostly of apatite (a-value 9.406 Å and c-value 6.888 Å), crandallite, and calcite. Roi-RP consisted mostly of quartz and variscite. Dissolution kinetics of PRs in 2% formic acid (2% FA), 2% citric acid (2% CA), neutral ammonium citrate (NAC), alkaline ammonium citrate (AAC), and deionized (DI)-water were determined. The dissolution rate of phosphate from PRs in 2%FA, 2%CA, NAC, and DI-water was NCR-PR > Rat-PR > Kan-PR > Roi-PR. As Roi-PR is very poorly soluble, it is clearly unsuitable for direct application to soil.  相似文献   

Nature of redox concentrations in a sequence of agriculturally developed acid sulfate soils in Thailand     

Tanabhatsakorn SUKITPRAPANON  Anchalee SUDDHIPRAKARN  Irb KHEORUENROMNE  Somchai ANUSONTPORNPERM  Robert J. GILKES 《土壤圈》2020,30(3):390-404

Potential acid sulfate soils (PASS) are drained for agriculture, resulting in the formation of active acid sulfate soils (AASS), which gradually evolve into post-active acid sulfate soils (PAASS). Various redox concentrations (precipitates, costings, and mottles) occur in these soils as a result of pedogenic processes including biological activity and effects of land management. Although several studies have determined the mineralogy and geochemistry of ASS, the mineralogy and geochemistry of redox concentrations occurring in a sequence of ASS through PASS to PAASS have not been investigated. This study examined the mineralogy and geochemistry of redox concentrations and matrices within 5 PASS, 8 AASS, and 5 PAASS in Thailand. The labile minerals were predominantly controlled by oxidation status and management inputs. The unoxidized layers of PASS, AASS, and PAASS contained pyrite and mackinawite. The oxidation of Fe sulfides caused acidification and accumulation of yellow redox concentrations of jarosite and Fe (hydr)oxides at shallow depths. As the soils became well developed, they were recognized as PAASS, and the jarosite and goethite transformed to hematite. As ASS were drained, Co, Mn, Ni, and Zn moved downward and were associated with Fe sulfides and Mn oxides in the unoxided layer. Concentrations of As, Cu, Cr, Fe, and V did not change with depth because these elements became associated with jarosite and Fe (hydr)oxides in yellow and red redox concentrations, as well as the root zone, in the partly oxidized layer of AASS and PAASS. Arsenic was associated with pyrite under reducing conditions.  相似文献