Major Plant Nutrient Release in Jasmine Rice Growing Soils Amended with Biochar and Organic Wastes: An Incubation Study

摘要

Background and Objective: Paddy soils for growing Jasmine rice in Thailand are mostly low fertile and possess some soil constraints of which efficiency of fertilization is low. Biochar and organic wastes can be used to amend these soils and a source of additional major plant nutrients. This study aimed at comparing the mineralization under incubation condition of major plant nutrients among biochar and organic wastes. Materials and Methods: Rich husk biochar (RHB), rice husk ash (RHA), cassava starch waste (CSW) and cassava tails and stalks (CTS) were applied into six soils and incubated in laboratory. The experiment was arranged in a Completely Randomized Design with three replications. No amendment application (control), cassava starch waste (CSW), cassava tails and stalk (CTS), rice husk ash (RHA) and rice husk biochar (RHB) were compared. The amounts of available N, P and K were measured at 0, 3, 7, 14, 30 and 60 days during the incubation. One-way analysis of variance (ANOVA) of data was performed with mean separation and Duncan?s multiple range test being considered significant at the p Results: CSW and CTS contained high OM content, 727.2 and 663.7 g kg^?1, respectively, resulting in high C:N ratio even though they also had high total N content (6.83-7.79 g kg^?1). The CSW also had higher total K content (10.18 g kg^?1) than did CTS, RHA and RHB (1.3-5.41 g kg^?1). Total P quantity in these organic materials varied little and was in a small amount ranging from 0.76-1.28 g kg^?1. The RHA and RHB significantly released greater available N and P than did CSW and CTS while the CSW and CTS clearly releasing more available K. Available K was constantly released from these materials throughout the incubation period whereas most of available N was freed within1 month and the amount declined markedly afterwards. Release patterns of N, P and K were similar among soils, indicating that different soil properties played a little part in the availability of major plant nutrients released from these soil amendments. Conclusion: This study suggested a potential use of biochar and organic wastes as soil amendments and an enhancement of major plant nutrients in Jasmine rice growing paddy soils.