Published in Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 23 ISSUE 2
Written by Claudia SZILAGYI, Maria BALA, Cristina TOȚA, Florin SALA

The study evaluated the quality of the flowers of the species Liatris spicata (L.) Wild., in relation to the date of planting and the fertilization applied. Planting was done at three different times, March 6 (PD1), March 13 (PD2) and March 20 (PD3). At planting, and at the formation of the floral stem, vermicompost type fertilizers were applied, in solid (VC-S) and liquid (VC-L) form, independently and in combination (VC-S/VC-L). Nine experimental variants resulted, including the control variant (T1 to T9). At the time of flowering, plant height (PH), flower stem length (FSL) and spike flower length (SL) were evaluated. The highest value for plant height was recorded under the conditions of planting date PD1 and fertilization VC-S/VC-L (T1), PH=52.05±1.11 cm. In the case of flower stem length (FSL), the highest value was in the PD1 variant with VC-S/VC-L fertilization (T1), FSL=42.70±1.44 cm. The highest value for the length of the spike-shaped inflorescence (SL) was recorded for variant PD2 with VC-S/VC-L fertilization (T4), respectively SL=9.95±037 cm. Polynomial equations of the 2nd degree described the variation of SL in relation to PH (R²=0.968, p<0.001) and FSL (R²=0.862, p=0.00264). According to PCA, PC1 explained 92.907% of variance, and PC2 explained 7.093% of variance. Regression analysis was used to evaluate the variation of SL in relation to PH and FSL, as a direct and interaction effect. 3D and isoquants models, plane format, were obtained to describe the variation of SL in relation to PH and FSL.

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