Zinc nutrition of rice as influenced by crop establishment methods, rates of nitrogen and phosphorus fertilization and inoculation with microbial consortia

Abstract

Zinc (Zn) fertilization in rice is important to enhance productivity and increase Zn concentration in rice grain to improve its nutritional status. A field experiment was conducted in wet seasons of 2013 and 2014 to study Zn nutrition of rice in three different crop establishment methods (CEMs) viz. puddled transplanted rice (PTR), system of rice intensification (SRI) and aerobic rice system (ARS), under three different rates of nitrogen (N) and phosphorus (P) viz. 0, 75 and 100% of recommended dose of fertilizer (RDF) (120 kg N ha−1 and 25.8 kg P ha−1) and two different sources of N and P viz. chemical fertilizer and microbial inoculation (MI). Concentration and uptake of Zn at different growth stages and in straw and milled rice was significantly higher in PTR and SRI than ARS. Soil DTPA–extractable Zn content of soil was increased by 1142.4, 1140.3 and 755.8 g ha−1 in PTR, SRI and ARS after two year of Zn fertilization (soil application of 5 kg Zn ha−1). Zinc nutrition increase its Zn concentration in straw and milled rice and improvement in total uptake was 38.1, 40.3 and 40.8 g ha−1 when Zn was applied with RDF, 75% RDF + Anabaena sp. (CR1) + Providencia sp (PR3) consortia (MI1) and 75% RDF + Anabaena-Pseudomonas biofilmed bio-fertilizer (MI2), respectively. Positive correlation between milled rice yield and Zn concentration (R2= 0.95 and 0.97) showed the importance of Zn nutrition in improving rice yield. Zinc concentration at 70 days after sowing (DAS) and 100 DAS was also found positively correlated with dehydrogenase activity and microbial biomass carbon in soil.