Difference of Light Quality Under Fly Nets with Different Colours and Its Effects on the Growth and Yield of Cowpea

【Objective】To investigate the difference of light quality under fly nets with different colors and its effect on the growth and yield of cowpea, and provide theoretical references for the light control technology of cowpea. 【Method】Open field was used as a contrast to study the spectral components and the difference in the growth period, growth characteristics, dry matter distribution and yield of cowpea under fly nets with seven different colors (coffee, yellow, red, green, blue, silver grey and white). 【Result】Compared with open field, under the fly nets, the proportion of far-red light and near-infrared light increased while the proportion of ultraviolet light and red light/far-red light decreased. In the green net, the proportion of green light and blue-violet light increased, among which the green light increased by 3.29%; while in the red net, the proportion of red light increased by 24.96% than the contrast; Under the fly nets, the sprouting time of cowpea was 5 to 7 days ahead of schedule, and the initial flowering of cowpea covered by yellow net, red net and blue net was earlier than that in the open field. Compared with the open field, the leaves thickness decreased significantly, and the plant height, single leaf area and internode length increased, among which the change under the red net was the most significant. The coverage of fly nets could increase the total yield and the yield at early stage of cowpea, among which the total output under the white net was the largest, followed by the green net, which were 43.46% and 42.02% higher than the contrast respectively. The difference between the two was not significant. 【Conclusion】It is recommended to use white nets or green nets in cowpea production to increase yield and release products earlier.