Grain yield and 15 N uptake of drill-seeded rice as affected by coated calcium carbide
1994
Bronson, K.F. | Mosier, A.R. | Bollich, P.K. | Lindau, C.W. (International Rice Research Inst., Los Banos, Laguna (Philippines))
Results of the study showed that grain yield responded positively (P0.05) to N rate in both years. An increase in grain yield with urea + CCC [coated calcium carbide] vs urea alone was only observed in 1990 at the highest N rate (P0.05). Addition of CCC to urea in 1990 resulted in small but significant (P0.05) increases in fertilizer-derived N (15N) uptake and dry matter production between 3 and 6 wk after fertilization compared with urea alone. This might suggest that nitrification-denitrification losses were a factor in the first year. A lack of response to CCC in the second year might have been related to a change in the coatings of the experimental CCC used. The coating materials used in CCC are mixture of waxes and shellac, applied in several layers. In preparing the CCC for the second year, more coatings were applied with the expectation that the release of acetylene would last longer. At the end of the season, however, much of the CCC applied was found on the soil, unreacted, indicating that the coatings were too thick. Improvement of the coatings is needed to give a more consistent release of acetylene so that CCC can be further tested in flooded rice
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