Analysis of problems in certain soils of the Kyushu Okinawa region for suitable management

Abstract

Soils in the Kyushu Okinawa region with problematic properties for agriculture were studied and the following findings were obtained. 1) Mahji-soils in Nansei Islands became very hard with desiccation under high-pH conditions; therefore, soil treatments that cause alkalinization such as overliming should be avoided. 2) In contrast to the generally favorable effects of organic matter on the physical properties of soil, the application of manure compost at 100 Mg ha −1 to Mahji-soils increased the degree of hardening with desiccation. 3) Application of clinker ash (coarse fraction of coal ash) at 10% (wt/wt) mitigated the hardening and shrinkage of Jagaru, a heavy-textured gray soil found on Nansei Island. 4) Non-allophanic surface horizons with strong acidity were widely distributed in the Andosol area of central Kyushu, covering at least 340 km 2. These horizons showed a relatively large ratio of carbon per Al p (pyrophosphate extractable aluminum) and high content of allophane, and began forming around 2500 years ago. 5)Some Andosols in Kyushu showed remarkable hardness. They are divided into two types, according to the degree of weathering and hardening characteristics, and the different measures required to improve each type. 6) An experimental method for determining nitrate retention by soils was developed, and factors influencing the nitrate retention of Andosols were elucidated using this method. 7) A method for micromorphological observation of pelletized manure compost (PC) grains was developed. This method revealed that the internal microstructure of PC did not change in 18 months after compost application, whereas the volume of the grains decreased with the formation of voids around them. 8) As an indicator of soil acidity concerning the countermeasure for common scab, pH(KCl) can easily be used instead of exchangeable acidity y 1, which is laborious to determine. The maximally simplified pH(KCl) measurement method can be carried out by farmers in the field.

Communicating Nitrogen Loss Mechanisms for Improving Nitrogen Use Efficiency Management, Focused on Global Wheat

“…This nitrate retention occurs especially in Oxisols, Ultisols, Alfisols, Spodosols, and Andisols [198]. Nitrate retention in these soils is attributed to the positive charge retaining the anion and preventing its downward leaching [199]. Verhagen and Laanbroek [176] report that this occurs more readily in allophanic Andisols than in Ultisols and Oxisols.…”

Contributions of Beneficial Microorganisms in Soil Remediation and Quality Improvement of Medicinal Plants

“…Soil structure and physical properties are destroyed due to the salinization and reduction of organic matter content, followed by the use of heavy-duty machinery in field management, which further hardens the soil [ 68 , 69 ]. Compacted soil weakens the permeability of water and air, hindering the transport and absorption of moisture and nutrients from the soil to plants [ 70 ].…”

Acceleration of Composting by Addition of Clinker to Tea Leaf Compost

“…While fly ash is effectively used as an additive to cement, clinker is not effectively reused, and there are concerns about socioeconomic and environmental issues if it is disposed of in landfills [31]. The particle surface of clinker is characterized by a porous structure, which has been used for applications in soil to improve its physicochemical properties [32,33], adsorb inorganic N and chemical oxygen demand (COD) in water [34,35], remove pathogenic microorganisms [36], and establish bacteria to restore desertified soil [37]. Clinker has also been used as a secondary material in cattle manure compost to improve drainage and aeration [38].…”