Ammonia loss from protected urea in soil under different irrigation depths

Abstract

This study presents an evaluation of the viability of using protected urea under different irrigation depths to reduce nitrogen losses caused by the volatilization of ammonia (NH3) under the conditions of the Southwestern Amazon. The study was carried out at the Experimental Station of Embrapa Rondônia, in the municipality of Porto Velho, Rondônia State, Brazil. The experiment was conducted in a Red-Yellow Latosol and arranged in a 5 x 6 factorial design consisting of a combination of five treatments (N sources) with six irrigation depths. The sources of N were as follows: 1) urea (45.5% N); 2) urea (44.3% N) + 0.15% copper and 0.4% boron; 3) urea (45% N) + NBPT; 4) urea (43% N) + sulfur (1%); and 5) control (without N). The irrigation depths were 0, 5, 10, 15, 20, and 25 mm. The results showed that, regardless of the use of urease inhibitors, an irrigation depth of 10 mm is suitable for incorporating urea into the soil and stabilizing N losses from NH3 volatilization. NBPT is the most efficient inhibitor under nonirrigated conditions. All N sources promote increases in the concentrations of nitric and ammonia nitrogen in the soil. In the first 15 days after fertilizer application, the highest concentrations of ammonium were in the 0 - 10 cm and 10 - 20 cm soil layers, and NBPT showed the highest ammonium content compared to that of the other sources in the 0 - 10 cm layer. The nitric nitrogen content in the soil was slightly influenced by the irrigation depth in the first 15 days after fertilizer application. However, the ammonia nitrogen content decreased exponentially with the increase in irrigation depth due to the movement of ammonia in the soil.

Stabilized urea for maize grown on an Amazonian Cerrado soil

“…This result highlights the importance of NI in soils with low effective cation exchange capacity and intense rainfall, such as the soil in the present study (Table 1 and Figure 1a). Thus, this inhibitor causes N to be close to fertilizer application sites (Espindula et al., 2021).…”

“…NBPT UI acts in the soil for up to 14 days. It delays and reduces NH 3 losses by volatilization, but does not fully inhibit them, losing efficiency over time (Espindula et al., 2021; Soares et al., 2012). Its use with reductions in the number of applications does not necessarily provide enough N for corn crops until critical growth stages.…”

Irrigation management of common bean cultivars with contrasting growth habits

“…It was applied in the sowing furrow during both years, with 04-20-20 formulated fertilizer as the source. Top-dressing fertilization consisted of 90 kg ha -1 of N applied 0.1 m from the sowing row at the V 4-3 stage of development (Fernández et al, 1985) during both years, with urea as the N source (Ambrosano et al, 1997) followed by an irrigation of 10 mm for all treatments (Espindula et al, 2021).…”