-
Article type: Cover
1998 Volume 42 Issue 2 Pages
Cover1-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Cover
1998 Volume 42 Issue 2 Pages
Cover2-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App1-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App2-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App3-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App4-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
T. UTSUGAWA
Article type: Article
1998 Volume 42 Issue 2 Pages
87-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Koh-ichi TOKUNAGA, Takashi SASE, Tomoyuki ISHIDA
Article type: Article
1998 Volume 42 Issue 2 Pages
88-96
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
The voids of soils sampled from 4 strata were imaged using contrast medium and X-ray stereography. The samples were from cumulative volcanic ash soils strata at Mugan-no-saka in Tokachi region of HOKKAIDO, and belong to the last interglacial and glacial epochs. Pore systems formed by roots were found in all strata, although in one stratum the pore systems had low density. It was confirmed that the oldest pore system extends over 100 ka at least. The pores of the low density and younger pore system, however, were decayed and the stratum containing this decayed pore system developed during the cold climate at the first half of the last glacial epoch (δ ^<18>O stage 4). This stratum was characterized by a phytolith assemblage that has exceedingly superior origin of Pooideae, and was disturbed by involution. We consider that the decayed pore system was caused by freezing and thawing. Furthermore, we suggest that the correspondence of pore system change with climate change means that pore system development may be an index of environmental change.
View full abstract
-
Hiwasa KAWAZU, Ikuo OTA, Katsutoshi SAKURAI
Article type: Article
1998 Volume 42 Issue 2 Pages
97-106
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
Soils in the farmland (reclamated upland field, upland crop field, and drained paddy field for upland crops) and the forest in Kochi, Japan were classified with the new set of variables including the data on conventional soil fertility plus charge characteristics and oxides contents. Furthermore, the soils were classified based on the total chemical composition and also on the water soluble fractions. All of these trials are to establish an appropriate classification system of farmland with highly variable history of land utilization. The following four systems were investigated; a) Soil classification by the conventional soil characteristics (8 variables) was easily affected by the current soil management and/or fertility management. Thus, it could not be regarded as a proper method for the soils with a various land use history. b) In addition to system a), four new index values (zero point of charge (ZPC), σ_p (remaining charge at ZPC), dithionite-citrate-bicarbonate soluble Fe, acid- oxalate soluble Al) were used (12 variables). Newly added indices could be considered as the properties which are not affected easily by the soil and fertility management. This system resulted in an appropriate soil classification to differentiate the various land use history. c) Soil classification using 10 mineral components of the soils reflected the properties of the parent materials and their weathering condition. However, the applied fertilizer was also found even in the subsurface soils greatly. d) Soil classification using water soluble fractions (anions, cations, low molecular weight organic acids, 15 variables) was mostly based on the amounts of them, and therefore, only the current soil management was reflected on this system. These results show the possibility of the soil classification system for various purposes through the selection of variables in need. Among them, the system using 12 variables (system b) gave the best classification for the manadgement and/or conservation of the farmland with various land use history.
View full abstract
-
Katsuhisa NIWA, Kiyoshi OHBUCHI, Koji KIKUCHI
Article type: Article
1998 Volume 42 Issue 2 Pages
107-116
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
Fine-textured brown lowland soils in the alluvial plain of Tokachi river used to have good chemical and physical properties and supported the high crop yields before heavy machinery was introduced to the fields. Recently, however, crop yields of the fine-textured brown lowland soils are decreasing. Therefore, we investigated the factors which decreased the crop yields in fine-textured brown lowland soils. We conducted soil profile surveys on an alluvial plain (900ha) at Makubetsu Town in Hokkaido, and prepared a basic soil map according to the "Classification of Cultivated Soils in Japan・Third Approximation". Brown lowland soils were dominantly distributed in our research area. Soil types with medium-texture were distributed a little apart from the small rivers. Soils with fine texture had more favorable chemical conditions. Clay mineralogy was almost the same among different soil types. With regard to the physical properities of soils, we found that the horizon just beneath the plow layer, especially in fine-textured brown lowland soils whose texture class belonged to SiC or SiCL, was characterized by a high bulk density and a low permeability. We assumed from these results that one of the factors responsible for the decrease of crop yields in the fine-textured brown lowland soils is the formation of tillage pan caused by the heavy agricultural traffics. We also presumed the reason for the formation of tillage pan in the fine-textured brown lowland soils with soil texture of SiC or SiCL. (1) Soil types with texture of SiC or SiCL had lower percentage of the pore space filled with easily available water than any other soil types, whether the effect of soil comperssion was large or small. (2) Soil types with texture of SiC or SiCL had a higher plasticity index than any other soil types. Therefore, the effect of soil comperssion by the agricultural traffics was more severe in this types of soils than any in other soil types. This caused the decrease in the percentage of pore space filled with gravitational water. Regradless of land use forms, micromorphology of the SiC or SiCL textured soil types showed a more compact state than the medium-textured soil types. We conclude from this that the soil types with the texture of SiC or SiCL have lower amount of easily available water than any other soil types, whether the effect of soil compperssion is large or small. According to the detailed soil map prepared by us, the soil types with the texture of SiC or SiCL occupy more than 50% of our research area.
View full abstract
-
Toru TAKAHASHI, Hiroshi TAKESAKO, Kan-ichi SAKAGAMI
Article type: Article
1998 Volume 42 Issue 2 Pages
117-127
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
We investigated that influences of Al/Si and contents of non-crystalline materials and meteological factors on the accumulation of humus in Andisols using multiple regression analysis. The total carbon contents as the quantities of he humus accumulation had a correlation with the acid oxalate extractable Si as the contents of non-crystalline materials. Further, the total carbon contents had a correlation with the Al/Si of non-crystalline materials. However, each correlation was impossible to explain accumulations of humus completely. Therefore, it was tried to use a multiple regression analysis. The result of the multiple regression analysis indicated that the humus accumulation was influenced by the contents and Al/Si of non-crystalline materials. It was considered that an active Al which was contained in the non-crystalline material promoted humus accumulation because the active Al induced humification. The quantities of the humus accumulation had a correlation with the temperature. We consider that high temperature caused plants growth, therefore many organic matter were supplied in soils.
View full abstract
-
Keiji TAKEMURA
Article type: Article
1998 Volume 42 Issue 2 Pages
128-137
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Kiyoshi HASEGAWA
Article type: Article
1998 Volume 42 Issue 2 Pages
138-143
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Shizuo NAGATSUKA
Article type: Article
1998 Volume 42 Issue 2 Pages
144-147
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Mamoru HOSONO, Takashi SASE
Article type: Article
1998 Volume 42 Issue 2 Pages
148-153
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
T. SASE
Article type: Article
1998 Volume 42 Issue 2 Pages
154-155
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Yoshihiro Kumayama
Article type: Article
1998 Volume 42 Issue 2 Pages
156-157
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Sota Tanaka
Article type: Article
1998 Volume 42 Issue 2 Pages
158-159
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
[in Japanese]
Article type: Article
1998 Volume 42 Issue 2 Pages
160-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
[in Japanese]
Article type: Article
1998 Volume 42 Issue 2 Pages
161-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
162-165
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App5-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App6-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App7-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Appendix
1998 Volume 42 Issue 2 Pages
App8-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Cover
1998 Volume 42 Issue 2 Pages
Cover3-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS
-
Article type: Cover
1998 Volume 42 Issue 2 Pages
Cover4-
Published: December 31, 1998
Released on J-STAGE: June 30, 2018
JOURNAL
FREE ACCESS