Ghazal, F., EI-Shahat, R., Abou-Zeid, M. (2006). DETECTION OF AZOLLA-N AND UREA-N CONTRIBUTION TO RICE BY THE USE OF 15N DILUTION TECHNIQUE.. Journal of Agricultural Chemistry and Biotechnology, 31(6), 3911-3919. doi: 10.21608/jacb.2006.204063
F.M. Ghazal; R. M. EI-Shahat; M. Y. Abou-Zeid. "DETECTION OF AZOLLA-N AND UREA-N CONTRIBUTION TO RICE BY THE USE OF 15N DILUTION TECHNIQUE.". Journal of Agricultural Chemistry and Biotechnology, 31, 6, 2006, 3911-3919. doi: 10.21608/jacb.2006.204063
Ghazal, F., EI-Shahat, R., Abou-Zeid, M. (2006). 'DETECTION OF AZOLLA-N AND UREA-N CONTRIBUTION TO RICE BY THE USE OF 15N DILUTION TECHNIQUE.', Journal of Agricultural Chemistry and Biotechnology, 31(6), pp. 3911-3919. doi: 10.21608/jacb.2006.204063
Ghazal, F., EI-Shahat, R., Abou-Zeid, M. DETECTION OF AZOLLA-N AND UREA-N CONTRIBUTION TO RICE BY THE USE OF 15N DILUTION TECHNIQUE.. Journal of Agricultural Chemistry and Biotechnology, 2006; 31(6): 3911-3919. doi: 10.21608/jacb.2006.204063
DETECTION OF AZOLLA-N AND UREA-N CONTRIBUTION TO RICE BY THE USE OF 15N DILUTION TECHNIQUE.
Soils, Water and Environ. Res. Inst., Agric. Microbiol. Dept., Agric. Res. Center (ARC), Giza, Egypt.
Abstract
Two field experiments were carried out simultaneously at Elsrew Research Experimental Farm Station (ARC) in the summer season of 2004, first one was to study the availability of labelled-N of Azolla (3% atom excess [a.e]) and urea (10 % atom excess) to rice plant var. Giza 171 at transplanting (TS) and maximum tillering stage (MTS), the second was to study the effect of Azolla pinnata inoculation in comparison with urea fertilizer on the rice yield components and the nitrogen content of rice grains and straw. Results in the first experiment indicate that Azolla used at the two stages exhibited higher values for all the labelled nitrogen parameters in comparison with unlabelled treatments. The highest values were 23 kg Nha·1 for labelled-N uptake, 14.5% for N- derived fertilizer and 76.8 % for 15N when labelled Azolla was applied at MTS. All the nitrogen values at TS were lower, but the values obtained with Azolla were higher than that with urea. Generally N applied later in the crop cycle is more easily absorbed than when applied at early stages as well as Azolla-N was more available to rice than was urea-No At maximum tillering, 76.8% of 15N from Azolla were recovered in the rice plant compared with only 42.9 % from urea. In the second experiment Azolla significantly increased rice yield (Var. Giza 171) and soil organic carbon. Increase in yield was 89.5 % (60 kg N ha,1 as urea), 81.5 % (60 kg N ha,1 as Azolla) and 92.1% (30 kg N ha" as urea + 30 kg N ha' as Azolla). Sixty kg N ha' as Azolla was almost equivalent the application of 60 kg N ha' as urea. The combination of urea and Azolla 30 kg N ha' each resulted in grain yield higher than that obtained with urea or Azolla alone but not significantly different from that obtained with 6.0 kg N ha' as urea. The increase of rice grain yield was associated with the increase in the number of panicles nnr' and the grain weight.
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