Effect of magnesium on crop yields within maize–green manure–T. aman rice cropping pattern on acid soil

Abstract

An experiment was conducted to study the response of maize to magnesium (Mg) and to find out the residual effect of Mg and green manure (GM) on transplanted aman (T. aman) rice in the maize–GM–T. aman cropping pattern. There were six treatments: T1 (recommended dose of fertilizer (RDF) + 0 kg Mg + 2 t CaCO3 ha−1), T2 (RDF + 10 kg Mg + 2 t CaCO3 ha−1), T3 (RDF + 20 kg Mg +2 t CaCO3 ha−1), T4 (RDF + 30 kg Mg + 2 t CaCO3 ha−1), T5 (RDF) and T6 (2 t CaCO3 ha−1). The response of maize to Mg was quadratic and the optimum dose of Mg was found to be 19 kg ha−1, which resulted in maximum yield of 10,507 kg ha−1. The residual effect of Mg along with GM and reduced dose of chemical fertilizer resulted in significant increase of grain yield of rice. Thus, N250P60K100Mg19S40Zn5B2 kg ha−1 for maize, only 20 kg N ha−1 for GM (Sesbania) and N60P9K33S10Zn1B1 kg ha−1 for T. aman appeared as the best combination for maximizing the productivity and may be recommended for this pattern at non-calcareous light-textured soils of Bangladesh. Application of lime increased soil pH, and this together with fertilizer and GM tended to improve soil fertility and thus may be recommended for soil amelioration.