Abstracts of Nippon Dojo-Hiryogaku Zasshi 92-3

A new proposal for the classification of peat materials distributed in Japan: Using the dataset of peat soils in Hokkaido

Mizuki Morishita*, Kimihiro Kida^# and Masayuki Kawahigashi

Department of Geography, Tokyo Metropolitan University, Tokyo, Japan; *Institute for Agro-Environmental Sciences, NARO; ^#Department of Forest Soils, Forestry and Forest Products Research Institute, Tsukuba, Japan

ABSTRACT

Well-decomposed peat materials are called ‘Muck’ or ‘Sapric peat.’ Ash content in peat materials is often used to distinguish the decomposition degree of peat materials worldwide. However, in the case of Japan, ash content does not always reflect the decomposition degree of peat materials. This is because alluvial or volcanic deposition frequently causes a high content of minerals in peat materials. Thus, Japanese peat materials tend to show high ash content, irrespective of the decomposition degree of organic materials. Hence, to design a new classification of peat materials reflecting characteristics and formation process of Japanese peat materials, we reviewed the definition and criteria of peat materials both within and outside Japan. Furthermore, cluster analysis using fiber and ash content relating to peat decomposition degree was conducted to distinguish the types of peat materials distributed on alluvial lowlands in Hokkaido, Japan. The discrimination criteria for each cluster were extracted by the decision tree algorithm. The suggested categories were as follows: fibric peat material (mineral depositic): fiber content ≥25 vol% and ash content ≥25 wt%, fibric peat material: fiber content ≥25 vol% and ash content <25 wt%, non-fibric peat material (mineral deposit): fiber content <25 vol% and ash content ≥45 wt%, non-fibric peat material: ash content <25 vol% and ash content <45 wt%. This classification system enabled us to explain that the high ash content in peat materials is either by the decomposition of organic materials or by the deposition of exogenous mineral materials.

KEY WORDS:

Ash content; decision tree; muck; peat; soil classification

(Jpn. J. Soil Sci. Plant Nutr., 92, 225-237, 2021)

Application of methane fermentation digestate to autumn–winter radish and its possibility to replace chemical fertilizers

Shoko Ishikawa

Division of Crop Production Systems, Central Region Agricultural Research Center, NARO

ABSTRACT

In Japan, attempts have been made on rice and various vegetables to replace chemical fertilizers with methane fermentation digestates. These reports often show successful replacement of chemical fertilizers by digestates in terms of crop yields. In contrast, only a limited number of reports are available that consider the replacement effects on nutrient concentration/content of the crops and the fertilizer efficiency of digestates. This study addressed the latter issue by conducting field experiments for 2 years on autumn–winter radish, especially using analysis of variance with contrast. Nitrogen fertilization of 50% and above the standard fertilization scheme following the fertilization guideline was replaced by a digestate containing approximately 2,000 mg L⁻¹ of water-soluble ammonium nitrogen. Compared with the plots that received standard fertilization, radish in the plots applied with the digestate was grown with a limited phosphate supply attributable to low phosphate concentration in the digestate. Radish yield was lower for the group replaced with the digestate than for the group fertilized solely by chemical fertilizers in the first year. In contrast, no statistical yield difference was observed between the groups in the second year. The fertilizer efficacy of the digestate for 2 years was estimated to be approximately 50% compared to the standard fertilization scheme that was set as 100%. The plots where all nitrogen was basal dressed, irrespective of whether it was applied as chemical fertilizers or the digestate, contained lower amounts of soil inorganic nitrogen after harvest than those applied with nitrogen both as basal and top dressings. In the scene of fertilization by digestates, application at once as the basal dressing was considered a feasible choice from the perspective of nitrogen leaching after harvest.

KEYWORDS:

Autumn–winter radish; fertilizer efficacy; field experiment; methane fermentation digestates

(Jpn. J. Soil Sci. Plant Nutr., 92, 238-248, 2021)

Original paper

The possibility of introducing variable-rate nitrogen application in uplands of andosol areas as evaluated by surface soil and crop growth attributes estimated from satellite images

Katsuhisa Niwa^a, Jun Yokobori^a, Kiwamu Ishikura^b, Keisuke Hara^b, Nobuhiko Fueki^b and Shinji Imada^c

^aZukosha Co., Ltd.; ^bTokachi Agricultural Experiment Station, Hokkaido Research Organization, Sapporo, Japan; ^cJapan Agricultural Cooperatives of Shikaoi Town

ABSTRACT

Variable-rate nitrogen application (VNA) based on nitrogen fertility has been introduced to upland fields in Hokkaido. This technique has been considered effective in fields where nitrogen fertility positively correlates with the variation in crop growth estimated from remote sensing, such as satellite images. This study estimated the surface soil humus contents (SSHCs) as an index of nitrogen fertility and aboveground growth of sugar beet and potato from satellite images in 123 fields in Andosol areas of Tokachi region, Hokkaido. Based on the relationship between the above-mentioned soil and crop data, we investigated the number of effective VNA fields. Two satellite images were used for the analysis, one in April 2016, when the surface soil was visible and another in July 2016 (a year of heavy rain) when the crop grew abundantly. From the image in April, we found the highest coefficient of determination (R²=0.71) for the red wavelength in the correlation between the image data and the measured value of SSHCs. Therefore, the SSHCs in the surveyed fields were estimated using the regression equation. Sugar beet and potato growth were evaluated using the normalized difference vegetation index (NDVI) of image data in July. The estimated SSHCs and NDVI were resampled by a 10 m grid, and then their relationship for each field was evaluated by linear regression. Resultantly, SSHCs were positively correlated with NDVI at a 1% level in 20 fields (34.5%) for sugar beet and 31 fields (47.7%) for potato. However, those fields with high SSHCs, which have a negative correlation could have been affected by poor drainage due to heavy rainfall or low pH. In conclusion, those fields with a positive correlation between SSHCs and NDVI in the year of heavy rainfall are effective for VNA introduction in the study area.

KEY WORDS:

NDVI; satellite image; surface soil humus content; variable-rate nitrogen application

(Jpn. J. Soil Sci. Plant Nutr., 92, 249-254, 2021)

Original paper

The effect of cultivation temperature on the soybean (Glycine max) growth and community structure of bradyrhizobia

Sokichi Shiro^a, Shinya Mazuka^a, Masayuki Kadowaki^a and Yuichi Saeki^b

^aFaculty of Life and Environmental Science, Shimane University, Matsue, Japan; ^bFaculty of Agriculture, University of Miyazaki, Miyazaki, Japan

ABSTRACT

We investigated the growth of soybean (Glycine max (L.) Merr.) under different cultivation temperature conditions, and the inoculation effect of useful bradyrhizobial strain and the community structure of infected soybean-nodulating bradyrhizobia to elucidate the effects of climate change on crop production due to global warming. ‘Orihime,’ ‘Bonminori,’ and ‘Fukuyutaka’ were used as the test soybean cultivars, and Bradyrhizobium diazoefficiens USDA110^T was used as the test strain. The soybean was grown in a temperature-gradient chamber with low-temperature zone, middle-temperature zone, and high-temperature zone. The results of cultivation test under different temperature conditions showed that inoculation with USDA110 significantly increased plant height, number of nodes, stem and leaf dry weight, the number of pods, pod dry weight, total plant dry weight, and number of nodules. However, all investigation items, except for the number of nodules, were significantly reduced with increasing cultivation temperature. Correlation coefficients were significantly positive in many combinations, including the relationship between the number of nodules and stem and leaf dry weight. The occupancy of USDA110 was dominated by inoculated USDA110 in all cultivation temperature zones. However, the occupancy tended to decrease with an increase in cultivation temperature when comparing low- and middle-temperature zones and low- and high-temperature zones. These results suggest that the decreased number of nodules under high-temperature conditions inhibited soybean growth, reducing the growth and yield of soybean. However, the reduction of soybean productivity due to the increase in cultivation temperature may be reduced by ensuring the number of nodules and occupancy of B. diazoefficiens USDA110^T.

KEY WORDS:

Soybean; cultivation temperature; bradyrhizobia; inoculation effect; community structure

(Jpn. J. Soil Sci. Plant Nutr., 92, 255–262, 2021)

Note

Calculation of the optimum fertilization level for spring planting onions in the Tohoku region of Japan

Kazuaki Kudo, Osamu Nagata* and Takehiko Yamamoto

Tohoku Agricultural Research Center, NARO; *Hokkaido Agricultural Research Center, NARO

(Jpn. J. Soil Sci. Plant Nutr., 92, 263–266, 2021)

Lecture

Pathways and dynamics of phosphorus supply to plants through organic substances 3. A consideration on the fertilizing effect of phosphorus in manures

AE Noriharu^a, Moriizumi Mihoko^b and Satoru Hobara^c

^aYanmar Agri Japan Co., Ltd,; ^bFaculty of Agriculture, Ryukoku University, Kyoto, Japan; ^cCollege of Agriculture, Food and Environment Sciences, Rakuno Gakuen University, Ebetsu, Japan

(Jpn. J. Soil Sci. Plant Nutr., 92, 267–272, 2021)

Miscellaneous

The review of soil management in response to the drastic revision of the Fertilizer Regulation Act

Masahiro Segawa^a, Hideo Kubotera^b, Minoru Takemoto^c, Ichiro Uezono^d, Wataru Oyanagi^e, Shinichi Moritsugu^f and Yusuke Arakawa^g

^aAgricultural Production Bureau, Ministry of Agriculture, Forestry and Fisheries; ^bThe Institute for Agro-Environmental Sciences, NARO; ^cThe Kanagawa Agricultural Technology Center; ^dOhsumi Branch, the Kagoshima Prefectural Institute for Agricultural Development; ^eNiigata Agricultural Research Institute Livestock Research Center; ^fThe Okayama Prefectural Technology Center for Agriculture, Forestry, and Fisheries; ^gThe Kyushu Okinawa Agricultural Research Center, NARO

(Jpn. J. Soil Sci. Plant Nutr., 92, 273–279, 2021)

Miscellaneous

Improvement measures of OECD Farmland Nitrogen Balance and propulsive direction of crop-livestock integration in Japan

Sadao Eguchi^a, Masayasu Asai^b, Masayuki Hojito^c, Michio Tsutsumi^d, Tsutomu Kanno^e, Yuki Akamatsu^f, Takeru Gounai^g, Kei Asada^a, Masahiro Kasuya^h, Akinori Mori^f and Takuji Sawamoto^h

^aInstitute for Agro-Environmental Sciences, NARO; ^bPolicy Research Institute, Ministry of Agriculture, Forestry and Fisheries; ^cTochigi Office, Snow Brand Seed Co., Ltd.; ^dWestern Region Agricultural Research Center, NARO; ^eNasu Research Station, Institute of Livestock and Veterinary Science, NARO; ^fPlant Biotechnology Institute, Ibaraki Agricultural Center; ^gAichi Prefectural Federation of Economic Agricultural Cooperatives; ^hDepartment of Sustainable Agriculture, Food and Environment Sciences, College of Agriculture, Rakuno Gakuen University, Ebetsu, Japan

(Jpn. J. Soil Sci. Plant Nutr., 92, 280–288, 2021)

Miscellaneous

Soil and fertilizer to make delicious fruit

Hiromiti Inoue^a, Ayumi Sawada^b, Osamu Kato^c, Kyousuke Yamamoto^d, Naoyuki Tamura^e and Shogo Yamamoto^e

^aInstitute of Fruit Tree and Tea Science, NARO; ^bApple Research Institute, Aomori Prefectural Industrial Technology Research Center; ^cYamanashi Fruit Tree Experiment Station; ^dTottori Horticultural Experiment Station; ^eResearch Institute for Agriculture, Okayama Prefectural Technology Center for Agriculture, Forestry and Fisheries

(Jpn. J. Soil Sci. Plant Nutr., 92, 289–294, 2021)

Miscellaneous

Activities of the soil education committee since 2000 and future plans

Hiroaki Sumida

College of Bioresource Sciences, Nihon University, Tokyo, Japan

(Jpn. J. Soil Sci. Plant Nutr., 92, 295, 2021)

Miscellaneous

Event report: The First International Symposium on Cool Earth via Microbes in Agriculture

Manabu Itakura

Graduate School of Life Sciences, Tohoku University, Sendai, Japan

(Jpn. J. Soil Sci. Plant Nutr., 92, 296, 2021)

Miscellaneous

Regional trends: Kantoh

Kazuyoshi Yamada^a, Yoshinari Ohwaki^b and Miwa Yashima^c

^aNagano Prefecture Agricultural Experiment Station; ^bCentral Region Agricultural Research Center, NARO; ^cGraduate School of Horticulture, Chiba University, Chiba, Japan

(Jpn. J. Soil Sci. Plant Nutr., 92, 297, 2021)