High-precision observations provide an efficient way to calculate greenhouse gas emissions from agricultural fields and their spatial and temporal distributions. Two high-resolution laser heterodyne radiometers (LHRs) were deployed in the suburb of Hefei (31.9°N 117.16°E) for the remote sensing of atmospheric CO₂, CH₄ and N₂O above rice paddy fields. The atmospheric transmittance spectra of CO₂, CH₄ and N₂O were measured simultaneously in real time, and the atmospheric total column abundance was retrieved from the measured data based on the optimal estimation algorithm, with errors of 0.7 ppm, 4 ppb and 2 ppb, respectively. From July to October, the abundance of CO₂ in the atmospheric column that was influenced by emissions from rice fields increased by 0.7 ppm CH₄ by 30 ppb, and by 4 ppb N₂O. During the rice growth season, rice paddy fields play a role in carbon sequestration. CH₄ and N₂O emissions from paddy fields are negatively correlated. The method of baking rice paddy fields reduces CH₄ emissions from rice fields, but N₂O emissions from rice fields are usually subsequently increased. The measurement results showed that LHRs are highly accurate in monitoring atmospheric concentrations and have promising applications in monitoring emissions from rice paddy fields. In the observation period, rice paddy fields can sequester carbon, and CH₄ and N₂O emissions from rice fields are negatively correlated. The LHRs have strong application prospects for monitoring emissions from agricultural fields.

Advances in optical sensing technology have led to new approaches to monitoring and determining crop seed vigor. In order to improve crop performance to secure reliable yield and food supply, calibrating seed vigor, purity, germination rate, and clarity is very critical to the future of the agriculture/horticulture industry. Traditional methods of seed vigor determination are lengthy in process, labor intensive, and sometimes inaccurate, which can lead to false yield prediction and faulty decision-making. Optical sensing technology offers rapid, accurate, and non-destructive calibration methods to help the industry develop accurate decisions for seed usage and agronomic evaluation. In this review, we hope to provide a summary of current research in the optical sensing technology used in seed vigor assessments.