Amelioration effects of the application of calcium peroxide and silicon calcium fertilizer in gleyed paddy fields

【Objectives】 Gleyed paddy soil is a main kind of low yield paddy soil in south China, its total area is above 2.5 million hectare in south China. Key characteristics of gleyed paddy fields are oxygen deficit and excessive accumulation of reducing substances due to long time waterlogging, which limit the rice root growth and yield advance. The objective of the present study is to study the meliorating effect of calcium peroxide and silicon calcium fertilizer in gleyed paddy fields by conducting a field experiment in PoyangLake region. 【Methods】 A field experiment was carried out to study the effects of the application styles of calcium peroxide and silicon calcium fertilizer on the rice yield, soil total reducing substances and soil physical and chemical properties in double rice gleyed paddy fields in Poyang Lake region from 2012 to 2013.The treatments contained no calcium peroxide and silicon calcium fertilizer (T1), silicon calcium fertilizer only (T2), calcium peroxide only (T3), combination of calcium peroxide and silicon calcium fertilizer (T4). The rice yield and soil total reducing substances of 4 rice growing seasons from 2012 to 2013 were analyzed and as well as the soil physical and chemical properties, rice straw and seed nutrient contents after rice harvest in typical rice growing season during 2012 to 2013. 【Results】 The single or combined application of calcium peroxide and silicon calcium fertilizer could increase rice yield in gleyed paddy fields, and the combination application of calcium peroxide and silicon calcium fertilizer could increase rice yield by 1.06-2.06 t/ha in single rice cropping, meanwhile the combination application of calcium peroxide and silicon calcium fertilizer could promote the transfer of K and P to rice seeds. The single application of silicon calcium fertilizer has no significant effect on soil total reducing substances in this study, but the single or combination application of calcium peroxide and silicon calcium fertilizer reduce the soil total reducing substances significantly, and the combination application of calcium peroxide and silicon calcium fertilizer could reduce soil total reducing substances by more than 1 cmol/kg compared to the treatments of T1 and T2. The soil total amounts of reducing substances increase with the increase of soil depth. The combination application of calcium peroxide and silicon calcium fertilizer could increase the content of 10 mm small aggregates significantly. The application of calcium peroxide or silicon calcium fertilizer only has no significant effect on soil nutrient contents, but the combination application of calcium peroxide and silicon calcium fertilizer could increase the soil organic carbon and available P significantly, and has no significant effect on the humus carbon, available K and total N in this study. 【Conclusions】The application of silicon calcium fertilizer could increase rice yield, but it has no significant effect on soil total reducing substances in gleyed paddy fields. The application of calcium peroxide could increase rice yield and meanwhile reduce soil total reducing substances. The combination application of calcium peroxide and silicon calcium fertilizer has stable effects on increasing rice yield, reducing soil total reducing substances and improving soil physical and chemical properties, so the combination application of calcium peroxide and silicon calcium fertilizer could be used to improve gleyed paddy fields in Poyang Lake region.