Development of sustainable and environmentally sound rice production technology using slags, iron containing materials

通过田间试验研究了矿渣组成的含铁物质(ICM)在减少稻田甲烷排放和增加水稻产量方面是否有效。在6种不同易还原铁和易分解有机质含量不同的土壤上，添加1kgm~(-2)ICM(1kgm~(-2)~(-2))提高了水稻产量，但连续2年不能缓解稻田甲烷排放。与没有ICM的土壤相比，所有被测试的商业ICM(10种材料)都增加了淹没水稻土的甲烷产生量。添加ICM提高甲烷产量的原因是ICM含有少量的可还原氧化铁，并通过提高土壤pH来促进有机质的分解。加入盐酸后，ICM的性能得到了改善。两种原生ICM提高了水稻产量和稻田甲烷排放，两种改性ICM与不添加ICM相比，水稻植株含硅量和产量增加了34-46%，甲烷排放减少了10-41%。改良的ICM没有提高水稻土的pH值，并提供了大量的可还原氧化铁。这就是为什么改进的ICM减少了淹没稻田的甲烷排放。结果表明，应用改良的含铁材料是一种可持续、无害环境的水稻生产技术的有效选择。

A field study was conducted to examine whether iron containing materials (ICM) composed of slags were effective in mitigating methane emission from paddy fields and increasing rice production. Addition of ICM (1kg m^<-2>) increased the grain yield of rice but could not alleviate methane emission for two years in paddy fields of 6 soils with different levels of easily reducible ferric iron and easily decomposable organic matter. All of the commercial ICM tested (10 materials) increased methane productions from a submerged paddy soil which was alluvial soil with low content of free iron oxide, compared with the soil without ICM. Increase of methane productions by addition of ICM was derived from the facts that ICM contained small amounts of reducible Iron oxide and stimulated organic matter decompositions by raising soil pH. The properties of ICM were improved by adding HCl. While two kinds of original ICM increased the grain yields of rice and methane emission from paddy fields, two kinds of altered ICM increased silicon contents of rice plant and the grain yields by 34-46 % and decreased methane emission by 10-41% compared with no addition of ICM. The improved ICM did not increased pH of the paddy soil and supplied large amounts of reducible iron oxide. That is the reason why the improved ICM alleviated methane emission from submerged paddy fields. It was concluded that the application of improved iron containing materials was effective option as a sustainable and environmentally sound rice production technology.