Comparative performance and economics of different zinc application approaches in Boro rice

Zinc deficiency is now very common in Bangladesh causing significant yield losses of different crops including rice. Due to zinc and other micronutrient deficiencies the high yielding rice varieties fail to produce their potential yield even under good management practices. Although many farmers have started applying zinc fertilizer they are not aware of proper dose and application method. Therefore, in many cases farmers are applying zinc fertilizers indiscriminately without considering the efficacy and economic output. Keeping those in mind the proposed study bears huge importance to elucidate and enrich the present state of knowledge on zinc fertilization in rice for ensuring food and nutritional security of Bangladesh in a sus- tainable way. An experiment was therefore conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from December 2020 to May 2021 to investigate the effects of different doses of Zn applied through soil, root soaking and foliar on rice growth and yield and their economics in Boro seasons following a random- ized complete block design with three replications. Two Boro rice varieties (BRRI dhan58 and Hira Dhan-1) and seven different zinc application ap- proaches (including soil application, root dipping and foliar spray of zinc with different dose/concentration) were considered as treatments. Hybrid variety Hira Dhan-1 performed better than BRRI dhan58. Application of zinc resulted in better crop growth and higher yield. Soil application appeared as the most efficient approach. Grain yield increased over control due to zinc application ranged from 5.1 to 14.7%. Present study confirms the necessity of zinc fertilizer application for increasing Boro rice yield. Among the different application approaches, soil application was found most effective and foliar spray was least effective. Although soil application of ZnSO4 @ 10 kg ha−1 produced the highest yield, application of ZnSO4 @ 5 kg ha−1 was the most economic one. Hybrid rice Hira Dhan-1 out yielded high yielding inbred variety BRRI dhan58. Therefore, it is recommended to cultivate hybrid rice in Boro season with soil application of ZnSO4 @ 5 kg ha−1 for higher yield and better economic return.