Effects of nitrogen fertilization on the seed quality of soybean(Glycne max. L) and its improvement by using slow-release nitrogen fertilizer.

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 18580061
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Plant nutrition/Soil science
• Research Institution: Kobe University
• Principal Investigator: SUGIMOTO Toshio Kobe University, Plant nutrition Lab., Professor (70240851)
• Co-Investigator(Kenkyū-buntansha): SHIRAISHI Naomasa Kobe University, Plant Nutrition Lab, Assistant Professor (00304121)
• Project Period (FY): 2006 – 2007
• Keywords: Nitrogen application / soybean / slow-release nitrogen fertilizer / seed protein / seed oil

Research Abstract

Effects of the nitrogen fertilizer applications on the yield and quality of soybean seeds were examined.
1) Grafting experiments showed that roots from plants of a cultivar having low-protein seeds affected seed protein concentrations responding to concentrations of nitrogen in growth medium.
2) Soybean cultivars were roughly classified into two types based on the response of plants against nitrogen fertilizers (changes of the seed yields by nitrogen application). One was that seed yields were increased by nitrogen fertilization and the other was that seed yields were not affected by nitrogen application.
3) Tanbaguro, a cultivar having biggest seeds with black coat, increased its seed size and oil concentration in seeds by the increase of amounts of nitrogen application during seed maturation periods. These results showed that inorganic nitrogen (fertilized nitrogen) absorbed during reproductive stage was converted to organic form (amino acids) and played a some role to increase yields. The observation that oil concentrations in seeds were increased by nitrogen fertilization suggested that suppression of nitrogen fixation would promote oil accumulation in seeds.