Effects of combined application of biological organic fertilizer and inorganic compound fertilizer on the tobacco profit and nitrogen use efficiency

A biological organic fertilizer (BOF) and a inorganic compound fertilizer (ICF) specified for tobacco were chosen to study the suitable ratio of their combined application. A pot experiment and a field trial were conducted and five treatments were designed to investigate their effects on the soil available N contents, the above ground dry matter accumulation and yield of tobacco, and the fertilizer nitrogen use efficiency. The results show that the contents of soil NO-3-N, NH+4-N and total N are significantly increased by 3.75%-118.14%, 0-16.35% and 0.77%-10.42% respectively during the whole tobacco growth stage, the above ground tobacco dry matter increased by 0.76%-51.88%, the tobacco yield increased by 8.63%-15.28%, the fertilizer N use efficiency was improved by 3.21%-208.38% and the partial soil productivity increased by 5.39%-27.24% with the combined ratio of 70% ICF-N plus 30% BOF-N in the 60 kg/ha application N rate, compared with the 100% ICF-N treatment and 100% BOF-N treatment and the other combined ratios. In conclusion, the combined ratio of 70% ICF-N plus 30% BOF-N in the application N rate 60 kg/ha is the best one that should be recommended for the tobacco production and profit.