Nutritive properties and optimum nitrogen fertilizer amount of edible burdock
1998
Nishida, T. (Hokkaido. Tokachi Agricultural Experiment Station, Memuro (Japan))
Nutritive properties and the optimum amount of nitrogen fertilizer applied were studied for "Late spring" edible burdock. The percentage of leaf nitrogen peaked on about day 60 after seeding, then gradually decreased. The percentage of root nitrogen after seeding decreased to about day 80, then remained constant until about day 120, after which it increased. The amount of leaf nitrogen absorbed decreased when leaves began to wither after attaining maximum growth on about day 115. The amount of root nitrogen absorbed increased after leaves withered completely. Total nitrogen absorbed peaked at about day 125-130 after seeding, reaching about 20 kg/10a. There after absorption decreased in proportion to progressive leaf withering, to about 17 kg/10a. Nitrogen application increased yield up to 18 kg/10a, but yield essentially remained unchanged, however fertilizer was increased. Root phypertrophy dry matter percentage, and inulin content decreased with fertilizer increase. Based on nitrogen requirement experiments at five fields, including the Tokachi Agricultural Experiment Station, we concluded that the optimum amount of nitrogen fertilizer applied was 18 kg/10a considering fertilizer yield, quality, and recovery rate. The amount of fertilizer can thus be reduced to 15 kg/10a or less infields, such as those with alluvial soil, having a high natural nitrogen supply
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