การตรึงไนโตรเจนของจุลินทรีย์อิสระในดินและผลกระทบที่มีต่อผลผลิตของข้าวโพดหวานในระบบการปลูกแบบไม่ไถพรวน

Abstract

Experimental design was split plot in randomized complete block design with 4 replications. Main plot consisted of conventional tillage and no tillage while sub plot consisted of 1) control 2) normal rate of chemical fertilizer 3) half rate of chemical fertilizer 4) azotobacter inoculation 5) azospirillum inoculation 6) soybean green manure and 7) mungbean green manure. The results showed no significant of nitrogen fixing microorganisms population, efficiency of nitrogen fixation and yield in various tillage systems, but various types of fertilizers had significant effect on them. The population of azotobacter and azospirillum were increased in application azotobacter and azospirillum treatments. Azotobacter treatment had the highest nitrogen fixation in soil (3.35 mg N/hr/square m), while those of azospirillum, soybean green manure and mungbean green manure treatments were lower, respectively. Nitrogen fixation in root from azospirillum treatment was the highest (0.04 mg N/hr/square m). The standard ears from normal rate of chemical fertilizer treatment was the highest (1,539 kg/rai), while those from azotobacter, azospirillum and mungbean green manure treatments were appeared in the same level as that from the treatment of half rate of chemical fertilizer. However the standard ears of control treatment was the lowest (947 kg/rai).