ISSN:
1573-0867
Schlagwort(e):
Azolla pinnata (Bangkok)
;
blue-green algae (BGA)
;
N accumulation
;
nitrogen fertilizer
;
rice
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
Notizen:
Abstract Application of higher levels (60 and 90 kg N ha−1) of nitrogen fertilizer (Urea) inhibited the growth ofAzolla pinnata (Bangkok) and blue-green algae (BGA) though the reduction was more in BGA thanAzolla. Inoculation of 500 kg ha−1 of freshAzolla 10 days after transplanting (DAT) in the rice fields receiving 30, 60 and 90 kg N ha−1 as urea produced an average of 16.5, 15.0 and 13.0 t ha−1 fresh biomass ofAzolla at 30 DAT, which contained 31, 31 and 27 kg N ha−1, respectively. The dry mixture of BGA (60%Aulosira, 35%Gloeotrichia and 5% other BGA on fresh weight basis) inoculated in rice field 3 DAT at a rate of 10 kg ha−1 showed a mat formation at 80 DAT with an average fresh biomass of 8.0, 5.8 and 4.2 t ha−1 containing 22, 17 and 12 kg N ha−1, respectively with those N fertilizer doses. Application ofAzolla showed positive responses to rice crop by increasing the panicle number and weight, grain and straw yields and nitrogen uptake in rice significantly at all the levels of chemical nitrogen. But, the BGA inoculation had a significant effect on the grain and straw yields only during the dry season in the treatment where 30 kg N was applied. During the wet season and in the other treatments performed during the dry season no significant increase in yields, yield components and N uptake were observed with BGA. The intercropping ofAzolla and rice in combination with 30, 60 and 90 kg N ha−1 as urea showed the yields, yield attributes and nitrogen uptake in rice at par with those obtained by applying 60, 90 and 120 kg N ha−1 as urea, respectively but, the BGA did not. The analysis of soil from rice field after harvest showed thatAzolla and BGA intercropping with rice in combination with chemical fertilizer significantly increased the organic carbon, available phosphorus and total nitrogen of soil.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01050456
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