Influences of Heavy Application of Nitrogen on Soil Acidification and Root Growth in Tea Fields

Autor:	Naoaki Tachibana, Katsuhiko Ikeda, Shigehiko Yoshikawa
Rok vydání:	1995
Předmět:	Soil test Chemistry Nitrogen deficiency Soil acidification Potassium chemistry.chemical_element Nitrogen chemistry.chemical_compound Agronomy Soil pH Environmental chemistry Soil water Genetics Agronomy and Crop Science Phosphoric acid Food Science
Zdroj:	Japanese Journal of Crop Science. 64:516-522
ISSN:	1349-0990 0011-1848
DOI:	10.1626/jcs.64.516
Popis:	We surveyed the actual levels of nitrogen application in the productive region of green tea in northern Mie prefecture and investigated the physico-chemical properties of the soils and root growth in the tea fields. The annual quantity of nitrogen supplied ranged from 5.8 to 28.3kg a-1, giving 14.7kg a-1 on average. The annual quantities of phosphoric acid and potassium were 5.7 and 4.6kg a-1 on average, respectively. More than 20kg a-1 of nitrogen had been applied annually for 11% of the surveyed tea fields. White roots in the topmost layer(0∼20cm) of inter-row soil were considerably reduced when nitrogen exceeding 14.0kg a-1 was applied and were not found when the amount of nitrogen exceeded 18.0kg a-1. The soil acidity (H2O) in the inter-row decreased from pH 5.9 to 2.9 with an increase in the amount of nitrogen applied. The topmost layer of inter-row soil was highly acidic lower than pH 4.5. Anions in the soil solution collected in the inter-row were mainly composed of NO3- and SO42- and the concentration of anions exceeded that of cations. The soil acidity was kept at pH 3 when alminium inos were available to compensate for the lack of cations.
Databáze:	OpenAIRE
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