Effect of Organic Amendments on Rice Yield and Soil Carbon Fraction in Paddy Soil

Abstract

In agricultural land, organic matter plays an important role in crop productivity by improving the physical properties of soil and supplying nutrients to plants. In this study, field experiment was carried out to assess the effect of three organic amendments, [HV(Hairy vetch), OCC(Oil Cake Compost), LMC(Livestock Manure Compost)] on paddy rice growth and soil carbon fractions. According to a survey of early rice growth after using organic amendments, there were 34.6 -37.9 cm in plant height and 11.3 -14.9 in number of panicles per plant, which was not different between the types of organic amendment and control rice growth and yield at the harvest were better in organically amended-plot that in the control. Based on growth parameters as affected by organic amendments, rice growth was better in the order of OCC > HV > LMC > Control. The number of panicle per m 2 was 591, which was 1.5 -1.7 times higher than that of other organic amendment, and about twice as high as that of the control. However, the percentage of ripened grain (76.5%) and the 1000-grain weight of brown rice (21.0 g) were lower than other organic amendment application. Rice yield was much better in oil cake compost (5.9 ton ha -1 ) than in other organic amendment treatments. Soil carbon content increased in all organic amendment application after the test. T-C content was high in OCC and lower in HV and LMC. The carbon content of each type was the largest with the Humin carbon content and the similar amount of humic acid carbon and fulvic acid carbon content. The proportion of soil carbon fraction was about about 59 -67% of humin carbon, 13 -23% of fulvic acid carbon content and 19 -26% of humic acid carbon. In conclusion, in view of rice yield and soil carbon, it is suggested that organic amendment can be advantageous to paddy soil and oil cake compost was considered potential resources as alternative chemical fertilizer.