Nutritional diagnosis by leaf color and nitrogen content for apple [Malus pumila] tree 'Hacnine' and 'Tsugaru'
2008
Inagawa, Y.(Hokkaido. Central Agricultural Experiment Station, Naganuma (Japan)) | Miki, N. | Muramatsu, H. | Yamaguchi, S.
The nutrition diagnosis using leaf nitrogen content was investigated for two apple cultivars (Hacnine and Tsugaru) to obtain proper yield and ground color of fruit skin at harvesting-period. The nitrogen content of ten leaves of young branches at height of approximately eye level was measured in early August. The diagnosis criteria were decided as follows. The upper limit of the leaf nitrogen content to obtain proper ground color for Hacnine and Tsugaru are 2.2% and 2.5%, respectively. The lower limit of the leaf nitrogen content to obtain proper fruit weight for Hacnine and Tsugaru are 1.8% and 2.2%, respectively; however, lower limit for Hacnine is tentative. The diagnosis criteria were applicable to 'many orchards in different years except those with poor drainage in year of heavy precipitation in August for Hacnine. For Tsugaru, exceptional case was found on the condition of less sunshine in July.
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