Identifying critical limit in soil and plant for determining response of rice (Oryza Sativa L.) to silicon application in periyar vaigai command area of Tamil Nadu, India

Abstract

A survey was undertaken during 2018 to assess silicon (Si) status of soils and to determine its critical limits in soils and plants. A total of 100 surface soil samples (0–15 cm) were collected from 7 major rice growing soil series of Periyar Vaigai Command (PVC) area of Tamil Nadu, India based on their percent coverage. Plant available Si in soils was extracted by 1 M sodium acetate (pH 4.0) and varied from 4 to 250 mg kg−1. Based on the results of pot culture experiment, the critical limit of Si for grain and straw of rice (Oryza sataiva L.) variety ADT-45) determined was 0.49 and 2.53 percent respectively. Similarly the critical limit of soil Si established was 122 mg kg−1. Based on this critical limit, soils were classified into low (< 122 mg kg−1), medium (122 to 181 mg kg−1) and high (> 181 mg kg−1). Rice plants were highly responded to Si application in soils below the critical limit of 122 mg kg−1 whereas soils with Si above 181 mg kg−1 did not respond. Among the levels of Si, 225 mg kg−1 of Si was found to be the optimal dose in Si deficient soils to get higher rice grain yield.