Field Deployment of the HT8700 for Paddy Field Ammonia Emission Flux Measurements


The weather gradually became warmer in April, and most parts of China have entered the new agricultural season. HealthyPhoton cooperated with our academic partners to carry out an ammonia emission flux test in paddy fields in Ningbo. The Eddy Covariance ammonia flux measurement system used in this experiment was based on our HT8700 high-precision laser-based ammonia analyzer. In the end, the experiment was not only a complete success, providing customers with valuable data, but also once again verified the reliability of the HT8700's all-weather work in an open environment.

Figure 1. Application engineer fixing equipment


Figure 2. The finished ammonia flux measurement system (Please note there is no sampling pump. The overall system power was ~60 Watts, which can be supported by a portable lithium battery running 24 hours continuously.)

After the system was installed, nitrogen fertilizer (ammonium bicarbonate) was uniformly applied to the fallow paddy field. The ammonia concentration and wind speed in the paddy field after fertilization was measured and recorded, for calculating the ammonia flux afterward.


Figure 3. Fertilization in paddy fields

Through data processing, the typical diurnal pattern of ammonia flux in the paddy field after fertilization were obtained, as shown below:

Figure 4. Typical diurnal pattern of ammonia flux after fertilization (data are shown as half-hourly interval)

Due to the high humidity in spring in southern China, the ambient ammonia concentration measured by the HT8700 was relatively low,  varying in the range of 1 to 5 ppb before fertilization. No obvious ammonia flux was obtained -- This is also agreed with expectations. After fertilization, the ammonia flux increased sharply. Within a few days afterward, the data continued to show a clear diurnal pattern in flux, that is, the ammonia flux reached its maximum near noon (Figure 4). Noise analysis showed that HT8700 has the detection limit of ~1 ng N m-2 s-1. Such sensitivity can measure the ammonia emissions of all nitrogen fertilizer events and the atmospheric ammonia dry deposition in urban areas and the areas affected by agricultural and animal husbandry activities.

    About us: As a leading R&D manufacturer of high-end gas analysis instruments in the industry and research communities, HealthyPhoton has cooperated with the Institute of Atmospheric Physics of the Chinese Academy of Sciences in-depth and successfully launched a novel laser-based open-path ambient ammonia analyzer (HT8700 series). We use the state-of-art leading quantum cascade laser spectroscopy technology. The open-path design overcomes the high adsorption nature of ammonia molecules on the surface of the inlet tube, leading to the reduction of the high-frequency attenuation (HFA) when performing ammonia flux measurement. The analysis of ammonia gas reaches unprecedented frequency and accuracy.

    Protecting the global environment and our mother Earth, HealthyPhoton is in action! We are committed to providing leading instruments and services for global ecology scientists. 

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