Characteristics of Extractable Soil Organic Nitrogen Determined by Using Various Chemical Solutions and Its Significance for Nitrogen Uptake by Crops
スポンサーリンク
概要
- 論文の詳細を見る
More than 90% of the nitrogen (N) in soil is bound in the form of organic N (N_<org>) compounds. Within the N_<org> in soil, the available N_<org> is considered to be a fraction of easily min-eralizable N_<org>. This N_<org> can be estimated based on the amount of released inorganic N when a soil is incubated under paddy and/or upland conditions at an appropriate temperature. However, incubation methods are time-consuming, and several methods of chemical extraction have thus been developed as substitutes for the incubation methods in many countries. In Japan, an extraction method using neutral phosphate buffer was proposed by Higuchi (Jpn. J. Soil Sci., 52, 481-489, 1981) and has been favorably evaluated throughout the country. We compared Higuchi's method with other methods of extraction, such as by 0.01 M CaCl_2 solution, electro-ultrafiltration (EUF), 0.05 M HC1, etc., and summarized the common characteristics of extractable N_<org> as follows : 1) similar C / N ratio ; 2) the primary constituent may consist of protein-like N compounds ; 3) the amino acid composition remains very similar, irrespective of soil types, kind of extractants, and organic materials added ; 4) the extractable N_<org> in the soil may be uniform in its molecular weight ; 5) these compounds are derived from the cell wall components of microorganisms, and 6) the extractable N_<org> is adsorbed on clay surfaces in soil, probably through binding to aluminum and iron, which protects it against microbial attacks, and this extractable N_<org> would be an important constituent of available N_<org> in soil. In addition, a recent study by Yamagata et al. (Plant Nutrient Acquisition-New Perspectives-, Springer-Verlag, Tokyo, 2001) demonstrated that plant growth and N uptake were enhanced when organic materials as N sources were applied to a soil, indicating that the amount of available N_<org> which increased by the application of organic materials may be taken up by certain species of crops before mineralization. If this phenomenon were to be confirmed more widely, it might be useful to examine the dynamics of available N_<org> in the plant rhizosphere.
著者
-
Matsumoto Shingo
Education and Research Center for Biological Resources, Faculty of Life and Environmental Sciences,
-
Ae Noriharu
National Institute of Agro-Environmental Sciences
-
Matsumoto Shingo
Education And Research Center For Biological Resources Faculty Of Life And Environmental Sciences Sh
-
Ae Noriharu
National Institute For Agro-environmental Sciences
関連論文
- Extraction of Soil Organic Nitrogen by Organic Acids and Role in Mineralization of Nitrogen in Soil (Soil Fertility)
- The Status and Origin of Available Nitrogen in Soils
- Nitrogen Uptake Response of Vegetable Crops to Organic Materials
- Characteristics of Extractable Soil Organic Nitrogen Determined by Using Various Chemical Solutions and Its Significance for Nitrogen Uptake by Crops
- Growth Responses of Cereal Crops to Organic Nitrogen in the Field (Plant Nutrition)
- Nutrient Distribution around Roots of Brachiaria, Maize, Sorghum, and Upland Rice in an Andisol
- Extraction of Organic Phosphorus in Andosols by Various Methods
- Genetic Variation in Acquisition, and Utilization of Phosphorus from Iron-Bound Phosphorus in Pigeonpea
- The Status of Inorganic and Organic Phosphorus in Some Soils in Relation to Plant Availability
- Genotypic Variation in Iron-, and Aluminum-Phosphate Solubilizing Activity of Pigeonpea Root Exudates under P Deficient Conditions
- Phosphorus (P) Uptake Mechanisms of Crops Grown in Soils with Low P Status : II. Significance of Organic Acids in Root Exudates of Pigeonpea
- Nitrogen Uptake Response of Crops to Organic Nitrogen
- Phosphorus (P) Uptake Mechanisms of Crops Grown in Soils with Low P Status : I. Screening of Crops for Efficient P Uptake
- 10-7 Relationships between microelements contents in rice and field water condition