Abstract

Zinc (Zn) and boron (B) are two of the most important micronutrients for plants which play vital role in various metabolic functions. However, deficiency of these nutrients elements in agricultural soils is very common and it has been associated with lower yield of rice in many regions of the world. Therefore, a field experiment was carried out at the Agronomy Field Laboratory of Bangladesh Agricultural University, Bangladesh during the period from May 2019 to August 2019 to study the effect of different levels of Zn and B fertilizers on the yield of Aus rice (cv. BRRI dhan48). The experiment included four levels of Zn fertilizer (ZnSO4.7H2O) management and three levels of boron fertilizer (boric acid) management. The Zn treatments were 0 kg/ha (control), basal application @ 10 kg/ha, basal application @ 5 kg/ha + soil application during active tillering stage @ 5 kg/ha, and foliar application (0.5% solution of ZnSO4.7H2O) during flag leaf stage. The B fertilizer managements were 0 kg/ha (control, 1.5 kg/ha basal application, and foliar application of 2% solution of H3BO3 during flag leaf stage. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Zn and B boosted all studied parameters of rice in comparison to their controls, i.e., no fertilization. The highest values for grain yield and almost all yield contributing characters of rice were obtained from foliar application of H3BO3 during flag leaf stage. The highest number of filled grains/panicle and grain yield were obtained from foliar application of ZnSO4.7H2O. The results also showed that grain yield of rice increased with increasing levels of both Zn and B up to 4.39 t/ha and 4.29 t/ha, respectively. For the maximum grain yield of Aus rice cv. BRRI dhan49, 2% solution of H3BO3 coupled with 0.5% of ZnSO4.7H2O solution should be applied during flag leaf stage. Further research should be conducted on different agro-ecological zones to assess the interaction between Zn and B in different soil types.