Pedosphere 30(4): 535--543, 2020
ISSN 1002-0160/CN 32-1315/P
©2020 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Effect of calcium silicate on nutrient use of lowland rice and greenhouse gas emission from a paddy soil under alternating wetting and drying
Hyun-Hwoi KU1,2, Keiichi HAYASHI1,3, Ruth AGBISIT1, Gina VILLEGAS-PANGGA2
1Crop and Environmental Sciences Division, International Rice Research Institute, Los Baños, Laguna 4031(Philippines)
2Farming Systems and Soil Resources Institute, Agricultural Systems Cluster, College of Agriculture, University of the Philippines at Los Baños, Laguna 4031(Philippines)
3Crop, Livestock and Environment Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-0851(Japan)
Corresponding Author:Hyun-Hwoi KU
      In intensively irrigated rice cultivation, plant-available silicon (Si) is a crucial nutrient for improving rice productivity. As a source of Si, calcium silicate (CaSiO3) was amended to evaluate the effect of silicate fertilizer on rice production, nitrogen (N) use efficiency, and greenhouse gas (GHG) emission under alternating wetting and drying in a pot experiment using a tropical soil from a paddy field of the International Rice Research Institute (IRRI) in the Philippines. Four levels of CaSiO3 amendment, 0, 112.7, 224.5, and 445.8 kg ha-1, with the recommended N rate were tested. The results showed that although CaSiO3 amendment of 112.7 kg ha-1 resulted in higher rice straw, improved N use efficiency, and reduced N2O emission, there was no difference in grain yield among the four levels of CaSiO3 amendment owing to relatively lower harvest index. Moreover, CaSiO3 amendment showed a reverse trend between CH4 and N2O emissions as it reduced N2O emission while led to significantly increased CH4 emission and global warming potential. Thus, CaSiO3 amendment was a possible alternative to improve N use efficiency and increase rice straw biomass, but it needs to be reviewed in line with grain yield production and GHG emission. It is also imperative to test an optimal method of silicate fertilizer amendment in future research in order to compromise a negative impact in tropical soils.
Key Words:  CH4 emission,N use efficiency,N2O emission,plant-available Si,rice straw biomass,silicate fertilizer,tropical soil
Citation: Ku H H, Hayashi K, Agbisit R, Villegas-Pangga G. 2020. Effect of calcium silicate on nutrient use of lowland rice and greenhouse gas emission from a paddy soil under alternating wetting and drying. Pedosphere. 30(4): 535–543.
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