Effect of algarization by increased inoculum rates of soil-based blue-green algae on growth and yield of transplanted rice
1989
Yanni, Y.G. | Zidan, M.I. (Agricultural Research Center, Giza (Egypt). Blue-green Algae Research Section)
A field experiment at Sakha Agricultural Research Station [Egypt] studied the effect of inoculum rate of blue-green algae (BGA) on growth and grain yield of rice. IRRI [International Rice Research Inst., Los Banos, Laguna, Philippines] rice line IR1626-203 was inoculated with soil-based algae in ascending rates of 100, 300, 600, and 1200 g/feddan. Two rates of mineral and N (urea), namely 15 and 30 kg N/feddan were used 1 mo after transplanting. Unlike straw yield, grain yield increased gradually but nonsignificantly with increasing rate of the inoculum up to 1.2 kg/feddan. Mineral N fertilization at 15 kg N/feddan, in combination with 600 g BGA inoculum/feddan gave maximum grain yield N content. Algarization at 1.2 kg/feddan was found necessary for obtaining a significantly higher grain yield N content with mineral N fertilization at 30 kg/feddan. Under mineral N fertilization at 15 kg N/feddan, straw yield N content responded only to algarization at 600 g inoculum/feddan. A maximum of 26.3 kg N/total grain + straw yield from a feddan was found to originate from biologically fixed N2 by BGA when 15 kg fertilizer N/feddan was applied along with 600 g of dried BGA soil-based inoculum. Plant height at harvest, number of effective tillers/hill, and percentage grain yield did not significantly change because of BGA or mineral N fertilization rates. Delaying fertilizer N application to 25 d after broadcasting of the BGA inoculum prevented significant interaction between mineral fertilizer doses and BGA rates.
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