Dependence of pigment content in meadow clover leaves on soil phosphorus level

In 2018-2019, the effect of different levels of soil phosphorus on the pigment complex of the clover (Trifolium pratense L.) leaves was assessed. Total chlorophyll content was 15.34-19.05 and 11.47-14.10 mg g- 1 dry matter, of which Chl a accounted for 9.64-11.36 and 6.67-7.98 mg g-1 (2018 and 2019 respectively). Carotenoids content varied within 2.69-3.12 and 1.52-1.88 mg g-1 in 2018 and 2019 respectively. Weight ratio of total chlorophyll/carotinoids (5.7-6.7 in 2018 and 6.8-9.6 in 2019) gives the grounds to consider that there was not disorders in structure of the pigment complexes of leaves in both year. There were statistically significant linkage of level of soil phosphorus with Chl a (r = 0.536-0.743) and Chl b (r = 0.725-0.748) in cooler conditions of 2019. In wormer 2018, these links were insignificant (Chl a = -0.146 to -0.286 and Chl b = -0.257 to -0.275). Correlation between phosphorus content in soil and carotenoids content in leaves was insignificant in all cases. Chl pigments showed a polynomial second order relationship with level of soil phosphorus. In 2019, these relations was statistically significant at p ≤ 0.05 (R2 = 0.68-0.76) for both chlorophylls. Under conditions of 2018 these relations was insignificant (R2 = 0.10-0.43).