Effect of low‐use‐rate zinc fertilization on rice growth and grain yield

Abstract

AbstractLow‐use‐rate Zn fertilization methods have been developed and marketed for rice (Oryza sativa L.) fertilization with limited research validating their efficacy. Our research objectives were to evaluate the effect of Zn‐seed treatment rate combined with six Zn‐fertilization methods on early season canopy coverage, tissue‐Zn concentration at the mid‐tillering stage, and rice grain yield. The field experiment was conducted on six silt loams and one clay. Rice seed was treated with 0 or 3.3 g Zn kg−1 as ZnO and combined with no Zn, granular ZnSO4 applied at 11 kg Zn ha−1 (GRAN), 1.68 kg Zn ha−1 as MicroEssentials (MESZ), 1.1 kg Zn ha−1 as foliar‐applied Zn‐EDTA (EDTA), and 0.56 and 1.12 kg Zn ha−1 of WolfTrax Zn‐DDP (DDP). Canopy coverage of seedling rice was measured at six sites and analyzed by site. Four sites were not affected by Zn‐seed treatment rate or fertilization method. At two sites, canopy coverage was affected by Zn‐fertilization method or the significant Zn‐seed treatment rate and Zn‐fertilization method interaction. Rice receiving MESZ had the greatest canopy coverage at these sites. When averaged across sites and Zn fertilization methods, seed treated with 3.3 g Zn kg−1 increased seedling tissue‐Zn concentration and biomass by 1.6 mg Zn kg−1 and 48 kg ha−1 respectively. Rice receiving GRAN, increased tissue‐Zn concentration by 7.6 mg Zn kg−1 above rice not receiving Zn (21.3 mg kg−1). Low‐use‐rate Zn fertilizers provide minimal Zn nutrition for rice seedlings and should be avoided on fields where Zn deficiencies are probable.