Effect of surface application timing of crushed fibrous-bamboo and intertillage and ridging on N_2 fixation and production of soybean (Glycine max L. Merr.) cv. Fukuyutaka

Abstract

Field experiments were performed on agricultural farm of Kyushu university to investigate the effect of surface application timing of crushed fibrous-bamboo (bamboo powder) and intertillage and ridging on N_2 fixation and production of soybean (Glycine max L. Merr.) cv. Fukuyutaka in 2005 and 2006. Moso bamboo (Phyllostachys pubescens Mazel) of 3 to 4 age was crushed in fiber-shaped and used as a bamboo powder. Treatments in 2005 were non-multi, early stage mulching, and late stage mulching, which bamboo powder was not applied, applied just after sowing or applied just after the cultivating and ridging, respectively. Treatments without cultivating and ridging in 2006 were F0, F40 and F80, which 0, 40 and 80kg 10a^<-1> of commercial chemical fertilizer (N; P_2O_5; K_2O=3.0; 10.0; 10.0%) without bamboo powder was applied on the surface of soil just after sowing, respectively and M0, M40 and M80, which 0, 40 and 80kg 10a^<-1> of compound fertilizer was applied on the surface of bamboo powder spread on soil just after sowing, respectively. All treatments had three replicates. The results in 2005 indicated that the surface application of bamboo powder decreased the soybean yield regardless of the application timing. Therefore, it was concluded that the cultivation method with cultivating and ridging was not suitable for the soybean production under the application of bamboo powder. The results in 2006 indicated the surface application of bamboo powder without cultivating and ridging increased the soybean yield. Because, the surface application of bamboo powder improved the germination and facilitated the growth from late vegetative to flowering stage. Furthermore, this method increased N2 fixation (relative abundance of ureides).