Tokachi Agricultural Experiment Station

Memuro, Japan

Tokachi Agricultural Experiment Station

Memuro, Japan
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Fueki N.,Tokachi Agricultural Experiment Station | Sato K.,Tokachi Agricultural Experiment Station | Sato K.,Hokkaido Abashiri Agricultural Extension Center | Takeuchi H.,Tokachi Agricultural Experiment Station | And 3 more authors.
Soil Science and Plant Nutrition | Year: 2011

To improve the prediction of nitrogen (N) uptake by sugar beet for the effective N fertilization, field experiments were carried out in 55 arable fields under various N management regimes throughout Hokkaido, Japan, from 2003 to 2006. The fields comprised nine soil types. Firstly, N uptake by sugar beet at different soil depths (0-20, 20-40, 40-60, 60-80, 80-100 cm) was examined using 15N-labeled fertilizer in Andosol fields in 2005. Secondary, soil nitrate N at a depth of 0 to 60 cm in the fields was determined to analyze the relationship between soil nitrate N and N uptake by sugar beet. Thirdly, the effects of soil type, the quantity of organic materials and fertilizers applied, and the history of land use on N uptake by sugar beet were investigated. Although sugar beet took up nitrate N mainly at the soil depth of 0 to 60 cm, N uptake at the depth below 60 cm was not negligible. Moreover, soil nitrate content at the depth of 0 to 60 cm could not evaluate N released by decomposition of applied organic matter during the cropping season. Therefore, the evaluation of soil nitrate content at the depth of 0 to 60 cm was not practical for predicting N uptake by sugar beet. However, sugar beet N uptake could be predicted by the sum of N-score and applied fertilizer N amount using a linear regression analysis (N-score is the estimated value of N available to the next crop from the applied organic matter, the incorporated crop residue and the other field practices). This predictability may indicate that sugar beet effectively takes up N released from the applied N sources, including fertilizer and organic matters, partly because of the plant's deep root elongation, long cropping period and harvest in autumn when the decomposition of organic matter has passed its peak. As a result of this study, it was concluded that this methodology (N-score) could be useful for farmers to decide the most effective N fertilizer management for sugar beet. © 2011 Japanese Society of Soil Science and Plant Nutrition.


Fueki N.,Tokachi Agricultural Experiment Station | Sato K.,Tokachi Agricultural Experiment Station | Nakatsu S.,Tokachi Agricultural Experiment Station
Soil Science and Plant Nutrition | Year: 2010

The objective of the present study was to investigate soil mineral nitrogen (N) in agricultural fields and to evaluate the factors that affect it. The amount of soil mineral N (0-100 cm depth) in 33 farming fields in the Hokkaido area, Japan, was investigated in April 2003, 2004 and 2005 (i.e. before sugar beet planting). The mean value and range of soil mineral N were 147 kg ha -1 and 44-750 kg ha -1, respectively. By analyzing six typical fields in detail (soil mineral N: 44-750 kg ha -1), we found that the history of organic matter application and other field management practices drastically affected the amount of soil mineral N. We referred to these histories and practices as "N-scores". These scores take into account organic matter application and other field management practices by scoring N input using the Hokkaido Fertilizer Recommendations 2002. Soil mineral N was more closely related to the N-score (r = 0.839**, P < 0.01) than to other soil factors (e.g. pH, total C, total N, cation exchange capacity and autoclaved N). These results suggest that evaluating organic matter application and other field management practices by scoring N input (N-score) is useful not only for evaluating soil N fertility, which is expressed by soil mineral N, but also for estimating the risk of N leaching. © 2010 Japanese Society of Soil Science and Plant Nutrition.


Fueki N.,Tokachi Agricultural Experiment Station | Takeuchi H.,Tokachi Agricultural Experiment Station
Soil Science and Plant Nutrition | Year: 2010

Vertical distribution of the root abundance of sugar beet (Beta vulgaris L.) down to a depth of 1.8 m and its relationship with soil properties were examined in four typical soils, Andosol, Brown Forest soil, Gray Upland soil and Gray Lowland soil, found in Hokkaido, Japan. The depth of the root distribution was in the following order: Andosol (150 cm) > Brown Forest soil (120 cm) > Gray Upland soil (90 cm) > Gray Lowland soil (60 cm). Andosol had no marked soil physical limitations. Both Brown Forest soil and Gray Upland soil had firm layers with a penetration resistance of more than 2.5 MPa measured using a cone penetrometer below a depth of 30 cm. However, the Brown Forest soil had a relatively higher air-filled porosity (>0.1 m3 m-3), and both Brown Forest soil and Gray Upland soil had visible cracks, which could provide space for the elongation of plant roots. Thus, roots in these two soils could elongate until they reached a deeper layer, irrespective of the hard subsoil. The Gray Lowland soil not only had a lower air-filled porosity, but also a gley layer below a depth of 66 cm. This anaerobic condition might restrict root elongation. Root distribution patterns in the four soil types were quite different and these differences were reasonably interpreted using soil physical properties (e.g. hardness, air-filled porosity, macropores and the existence of a gley layer). The order of sugar beet yields at harvest corresponded to the difference in root distribution patterns. © 2010 Japanese Society of Soil Science and Plant Nutrition.

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