Synergistic Effect of Urease and Nitrification Inhibitors in the Reduction of Ammonia Volatilization

Nitrogen (N) is deficient in more than 90% of soils of Pakistan, mainly because of low organic matter contents. The use of nitrogenous fertilizers is a common practice for sustainable and profitable crop yields. A significant portion of added fertilizers is lost through volatilization, leaching, and denitrification. The low use efficiency of these fertilizers in our climate is a serious concern because of high costs and environmental issues. The present study evaluated the novel synergistic effect of urease and nitrification inhibitors such as ammonium thiosulfate (ATS) and 2-Chloro-6-(trichloromethyl)pyridine (nitrapyrin) to reduce the urea hydrolysis in the soil of three cities of Pakistan, i.e., Faisalabad, Gujranwala, and Sheikhupura, to manage the ammonia as well as N loss. Three different combinations, such as A1, A2, and A3 of both inhibitors, were prepared with varying ratios of 1:1, 0.25:0.75, and 0.75:0.25, respectively. Results showed that the minimum urea hydrolysis of about 2.41, 2.79, and 4.68 IU/g soil was observed with A1 combination after 4th-day observation with the rate of 0.50% concentration for Faisalabad, Gujranwala, and Sheikhupura, respectively. In addition, results showed better urease activity at a pH value of 6.50, incubation time of 30 min, and temperature of 37 °C for all A1, A2, and A3 combinations with 0.50% concentration. Moreover, inhibitor-treated urea showed the maximum plant height of 111, 101, and 101 cm, and root length of 15, 11, and 5 cm, number of tillers of 14, 16, and 19 per panicle, and number of spikes of 37, 21, and 38 per panicle with A1, A2, and A3 combination at 0.50% dose respectively in Faisalabad soil. Overall, it is concluded that 0.50% inhibitor concentration showed the much impressive urease inhibition results followed by 0.25 and 0.10%. However, the application of inhibitors was a good practice to reduce the N loss from soil. Graphical abstract: [Figure not available: see fulltext.]