Photosynthesis in plants cannot occur without light radiation. In agricultural production, light conditions directly affect crop yield and quality. During plant growth, the spectral composition of the irradiating light source, the illumination of light radiation, and the coordination of light and dark periods all have a significant impact on the physiological characteristics of plants. Traditional agriculture can only passively adapt to the sunlight irradiation and its daily and seasonal changes, to create a suitable light radiation environment for plant growth. Modern intelligent agriculture, on the other hand, can apply science and technology to achieve effective regulation of the light radiation environment.
What exactly is photosynthetically active radiation?
Photosynthetically active radiation refers to the solar radiation energy that can be absorbed and transformed by light and pigment during the photosynthesis process of green plants. The wavelength of photosynthetically active radiation is in the range of 380 ~ 710nm, which is basically the same as visible light. The proportion of photosynthetically active radiation in direct solar radiation increases with the increase of solar altitude angle and can reach 45%. And in the scattered radiation, the proportion of light table effective radiation can be up to as much as 60 ~ 70%, so cloudy days on the contrary increased the proportion of PAR. On average, the light table effective radiation accounts for about 50 per cent of the total solar radiation.
Why is it important to monitor photosynthetically active radiation?
Light table radiation is a very important environmental factor for plant growth. In facility agriculture, different crop varieties and different stages of growth and development require different light intensity and duration. To achieve good planting results, it is necessary to regulate the appropriate light intensity and duration according to the growth and development laws of plants. Therefore, reasonable regulation of photosynthetically active radiation can not only effectively save light electricity, but also further improve crop yield and quality..png)
Photosynthetically active radiation can be measured directly by instruments. It is measured, for example, using the photoelectric sensing principle, by means of aPAR sensor equipped with a high-precision photoelectric sensing element.When there is light, the use of light throwers will be focused by the lens, through the transmission and to the light receiver mirror, and then to the receiving sensor, the sensor grid received light signals into electrical signals and then transmitted to the platform, can effectively measure the amount of photosynthetically active radiation in the environment.
Estimates of photosynthetically active radiation can also be made from direct solar radiation. To obtain scaling factors between direct and scattered solar radiation and photosynthetically active radiation, a heliometer or sky radiation meter and a photosynthetically active radiation meter can be synchronized to calculate the values of the coefficients and their correlation on a daily, monthly seasonal and annual basis.
With the continuous development of modern agriculture, how to carry out agricultural production more efficiently and energy-saving has become a problem that needs to be thought about on the road of agricultural development. By mastering the law of influence of effective radiation intensity of light table on crop growth and development, crop yield and quality can be further improved.
