Abstracts of Nippon Dojo-Hiryogaku Zasshi, Vol. 88 No. 4

Development of a soil physico-environmental database on prefectural scale for Japanese agricultural land for evaluating soil temperature and moisture

Takahiro Takimoto, Yusuke Takata and Tsuneo Kuwagata

Institute for Agro-Environmental Sciences, NARO

Available database on soil physical properties in each soil classification is uniform throughout Japan. Therefore, it remains to be clarified how soil properties are spatially distributed at the prefectural scale. To quantify the soil physico-environmental properties in each prefecture, we comprehensively analyzed the saturated volumetric water content, saturated hydraulic conductivity, and soil moisture characteristics using a dataset compiled by The Basic Soil Environment Monitoring Project. The saturated volumetric water content in the fine-textured lowland soils was high in the northern part of Japan where the organic matter content is high. Andosols had less available water than the other soil types because of its lower bulk density and higher water retention. These results will be useful for fine-scale modeling calculations or agricultural management.

Key words: Available water content, database on soil physical properties, saturated hydraulic conductivity, saturated volumetric water content

Ameliorative effect of liming on the availability of phosphorus applied to acid Andosols varies with the soil type and phosphorus source

Teruo Matsunaka*, Akira Nakamura and Ayumi Hashimoto

College of Agriculture, Food and Environmental Sciences, Rakuno Gakuen University

*Present address: Hokuren Federation of Agricultural Cooperatives

(Jpn. J. Soil Sci. Plant Nutr., 88, 318–326)

We performed a pot experiment to examine the effect of liming on phosphorus (P) uptake and growth of corn (Zea mays L.) in allophanic and non-allophanic Andosols using three different P sources. Both soils have similar properties: a rich humus, high phosphate retention, low pH (<4.9), and low available P status. The non-allophanic Andosols contained high exchangeable aluminum (Al), whereas Al level was low in the allophanic Andosols. The P sources included a superphosphate (SP) and two kinds of biochar, the latter derived from dairy cattle carcasses charred at different temperatures: low (450°C for 4 h) and high (1000°C for the first 0.5 h and then 450°C for a further 3.5 h). The availability of P applied to the acid Andosols was affected by the liming, soil type, and P source, and there was a statistically significant interaction between these factors. With SP applied to the non-allophanic Andosols, liming was essential to increase plant growth and P uptake, whereas in the allophanic Andosols, the liming was not required. The high exchangeable Al content of the non-allophanic Andosols without liming caused root damage and prevented the absorption of the applied P. By contrast, the exchangeable Al content of the allophanic Andosols was insufficient for Al toxicity, even without liming, and P availability was unaffected by liming. In the case of the biochars, liming decreased the availability of P in both Andosols, because the dissolution of P from the biochars increased by a low soil pH. Particularly for the non-allophanic Andosols without liming, with biochars applied, the plants grown did not show Al toxicity, although the exchangeable Al content in the soil was almost the same as where Al toxicity had occurred under SP application. The reasons for the different results between SP and the biochars treatments were unclear, and hence, further studies are needed to evaluate these differences. Based on the above results, we conclude that the ameliorative effect of liming on the availability of P applied to acid Andosols is not always reliable and varies with the soil type and P source.

Key words: Andosols, biochar, liming, phosphorus, superphosphate

Estimation of total nitrogen content in surface paddy soils by measuring their electrical conductivity after hydrogen peroxide treatment

Naoki Moritsuka^a, Kaori Matsuoka^b, Keisuke Katsura^c, Shuji Sano^d and Junta Yanai^e

^aKyoto University

^bInstitute of Fruit Tree and Tea Science, NARO

^cTokyo University of Agriculture and Technology

^dResearch Institute of Environment, Agriculture and Fisheries, Osaka Prefecture

^eKyoto Prefectural University

(Jpn. J. Soil Sci. Plant Nutr., 88, 327–335)

We proposed a simple, inexpensive method for estimating total nitrogen (N) content in surface paddy soils by measuring their electrical conductivity after a hydrogen peroxide treatment. In this method, 5 g of air-dried, 2-mm sieved soil was extracted with 100 mL of a commercially available Oxydol® (approximately 3％ H₂O₂). After extraction with Oxydol at 25°C for 40 h, the electrical conductivity of the soil extract [EC (H₂O₂)] was measured. For the six paddy soil samples, the coefficient of variation for the average of five repeated analyses of EC (H₂O₂) was less than approximately 2％, indicating a high reproducibility of the method. The temperature during the extraction significantly influenced EC (H₂O₂) values, and the temperature at 25°C was found more suitable than either 20°C or 30°C. Furthermore, the relationship between EC (H₂O₂) and total N content was evaluated at two sampling scales: (1) the national scale, with samples collected from paddy fields throughout Japan (n = 83) and (2) the field scale, with samples collected from eight fields in Mifune town (n = 39) and five fields in Takatsuki city (n = 246). The coefficient of determination between EC (H₂O₂) and total N content was 0.70 for the nationwide samples, excluding 11 volcanic ash soils, whereas it was 0.68 and 0.23 for the Mifune and Takatsuki samples, respectively. The low accuracy of estimation for volcanic ash soils and some of the Takatsuki samples was mainly due to the low rate of mineralization of soil organic N by the Oxydol treatment. Compared with the soil lightness (L* value), as measured by a soil color reader, EC (H₂O₂) could estimate the total N content with greater accuracy for both the nationwide and field-scale samples, provided that the volcanic ash soils were excluded.

Key words: electrical conductivity, evaluation scale, Oxydol®, paddy soil, total nitrogen

Note

Simple and rapid soil microbial biomass evaluation method using ATP measurement kit

Yasufumi Urashima^a, Toshihiko Karasawa^a, Hiroko Nakatsuka^a, Masaki Hayashi^a and Shin-ichi Tokuda^b

^aCentral Region Agricultural Research Centre, NARO

^bInstitute of Vegetable and Floriculture Science, NARO

(Jpn. J. Soil Sci. Plant Nutr., 88, 336–338)

Lecture

4. Application of spatial statistics in soil science

Kazuya Nishina

National Institute for Environmental Studies

(Jpn. J. Soil Sci. Plant Nutr., 88, 339–345)

Miscellaneous

How can plant nutrition contribute to solving soil problems in tropical Asia?

Masaru Kobayashi^a, Hiroyuki Koyama^b, Toshihiro Watanabe^c, Eriko Maejima^c, Anongnat Sriprachote^d, Kumiko Ochiai^a, Akifumi Shimizu^e, Motohiko Kondo^f, Yoshiko Iizumi^g, Takeshi Watanabe^g, Keitaro Tawaraya^h and Akira Watanabe^f

^aGraduate School of Agriculture, Kyoto University

^bFaculty of Applied Biological Science, Gifu University

^cFaculty of Agriculture, Hokkaido University

^dFaculty of Agriculture, Khon Kaen University

^eSchool of Environmental Science, University of Shiga Prefecture

^fGraduate School of Bioagricultural Science, Nagoya University

^gJapan International Research Centre for Agricultural Sciences

^hFaculty of Agriculture, Yamagata University

(Jpn. J. Soil Sci. Plant Nutr., 88, 346–351)

Change and issues of agricultural environment, products and economies after 5 years from the FDNPS accident

Hirofumi Tsukada^a, Takuro Shinano^b, Mamoru Satou^c, Sadao Eguchi^d, Noriko Yamaguchi^d, Shinji Kaneko^e and Ryota Koyama^f

^aInstitute of Environmental Radioactivity, Fukushima University

^bTohoku Agricultural Research Center, NARO

^cFruit Tree Research Center, Fukushima Agricultural Technology Center, Fukushima

^dInstitute for Agro-environmental Sciences, NARO

^eCenter for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute

^fFaculty of Economics and Business Administration, Fukushima University

(Jpn. J. Soil Sci. Plant Nutr., 88, 352–360)

Reports on 18th International Conference of International Humic Substances Society

Akira Watanabe

Laboratory of Resources Cycling in Pedosphere, Graduate School of Bioagricultural Sciences, Nagoya University

(Jpn. J. Soil Sci. Plant Nutr., 88, 361)