Seasonal dynamics of growth of varieties and wild samples of perennial forage crops in the conditions of the Leningrad region

Abstract

Forecasting of plant productivity with the help of mathematical models is in demand in the field of precision agriculture. The work is devoted to determining the optimal timing of harvesting for green mass using theoretical growth curves in 37 samples of perennial grasses. The theoretical curves were constructed on the basis of Richards equation. The study of samples was carried out in the Leningrad Research Institute of Agriculture. The accounting was carried out in the spring and summer periods of 2018. Models were built for 37 samples. Three models had low convergence. The point of inflection wasn’t determined for 8 samples. The rest 26 had high reliability and correlation between empirical data and the model curve. Among the samples of cocksfoot, tall fescue and bromegrass the variability in the potential height of plants, the growth rate at an exponential site and the rate of reaching the inflection point to the asymptote were observed. The samples of tall fescue were homogeneous in the model parameters. The most early matured varieties were Serebristy (21st of May) and Leningradskaya 204 (20th of May); their esti mated hay ripening began after 40 and 36 days. Late estimated hay ripeness was observed in the samples of tall fescue (55-62 days), bromegrass (Chishminsky 3 - 49 days), cocksfoot (Leningradskaya 853 - 53 days and wild samples: k-44349 from Leningrad region - 51 days and k-44354 from Komi Republic - 53 days. The recommended model is applicable for the majority of the studied samples. The use of the offered model allows to optimize the date of mowing taking into account the varietal belonging.

Keywords

• mathematical model
• perennial grasses
• growth
• forecasting