Determination of Calcium Carbonate Equivalent of Rice Husk Ash

Rice husk ash is one of the widely available agricultural wastes in rice producing countries, with potential to replace limestone and also supply some of the nutrients which are beneficial for crop growth. This study was conducted to determine the effective calcium carbonate equivalent (ECCE) of rice husk ash added to an acid soil. The design used in this study was completely randomized block design with 12 treatments and 3 replications. An incubation experiment was carried out in the post graduate laboratory of Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, Coimbatore, during Feb – March 2022.The incubation experiment was conducted for 4 weeks with eight levels of reagent grade CaCO3 (0.0, 0.5,1.0, 1.5, 2.0, 3.0, 4.0 and 5.0g kg-1 soil) and four levels of rice husk ash equivalent to 2.0, 3.0, 4.0 and 5.0 g CaCO3 kg-1 soil and analysed for pH at weekly interval. Results showed that soil pH increased in all the treatments received CaCO3 or rice husk ash with advancement of incubation period. Application of CaCO3 5.0 g kg-1 soil recorded significantly highest soil pH at all stages of incubation followed by CaCO3 4.0 g kg-1 soil and RHA 48.5 g kg-1 soil which were statistically on par. The TCCE (determined by titration method) and ECCE (determined by incubation with the soil) of rice husk ash used in this experiment were 10.3% and 6.41% respectively. Results of the present study showed that rice husk ash can be used as an amendment for acid soil reclamation.