Effect of some facilitators on growth characteristics of Trifolium repens L.

Background and objectives: The application of growth-facilitator materials to improve germination, early establishment, and plants growth can increase the success of rangeland improvement, planting, and pasture construction projects. In addition, growth facilitators can improve the quantity and quality of vegetation cover and production in dry-farming lands by increasing the success of cultivating forage plants. Therefore, it's critical to focus on the utilization of growth facilitators that are both accessible and cost-effective. The main purpose of this study was to investigate the effect of zeolite, bentonite and potassium nanochelate treatments on the growth of Trifolium repens in the greenhouse so that if the positive effects of these facilitators are proven, these materials can be used in rangeland improvement operations. Methodology: This study was performed to investigate the effect of zeolite (2, 4 and 6 g/kg), potassium nanochelate (30, 60 and 90 mg/kg), bentonite (2, 4 and 6 g/kg) and composition of potassium nanochelate + zeolite (2+30, 60+4 and 90+6) on the growth characteristics of Trifolium repens in the greenhouse. The study was conducted as a factorial with three replications using a completely randomized design. To conduct the research, the required soil was collected from 5 random points of rangelands in Fandaghloo region located 35 km from Ardabil city. Soil samples were taken from the rooting depth of rangeland plants (0- 30 cm). The soil samples were combined next, and the root, stone, and pebble components were separated using a 4 mm sieve before being mixed with the treatments and then placed into pots. At the end of growth season, height, volume, fresh and dry weight of shoots, root fresh and dry weight, root volume, root length, percentage of establishment, total chlorophyll index, electrolyte leakage, leaf relative water content and membrane stability index were measured. Duncan's test was used to compare the means and one-way ANOVA was utilized to explore the influence of facilitators. Results: The results of one-way ANOVA showed that the effect of treatments (zeolite, bentonite, potassium nanochelate and combination of potassium nanochelate + zeolite) on fresh and dry weight of shoots, fresh and dry weight of roots, root length, root volume, root area and the percentage of seedling establishment was significant. So that, the highest amount of fresh and dry weight of areal parts (26.83, 88.59 g), root area (61.44 cm2) and root volume (50.00 ml) in the treatment of potassium nanochelate 90 mg/kg + zeolite 6 g/kg was observed. The highest amount of fresh root weight (56.48 g) was observed in the treatment of potassium nanochelate 60 mg/kg + zeolite 4 g/kg. Root dry weight (25.21 g) showed the highest value in nanochelat 90 mg/kg. The highest increase in plant establishment (83.31%) was caused by Bentonite 4 g/kg. Chlorophyll index (46.53) showed the highest value in potassium nanochelate 30 mg/kg. The bentonite treatment of 4 g/kg provided the largest percentage of leaf relative water content, which was around 31% greater than the control. Conclusion: In general, the most effective treatment for enhancing growth factors and increasing production of Trifolium repens was the combination of potassium nanochelate and zeolites facilitators. It seems that due to the need of T. repens for potassium and on the other hand, the uptake and retention of potassium particles by zeolite and consequently its uptake by the plant during the growth period, has increased the growth and production of this plant. As a result, this treatment has benefited both the shoots and roots of T. repens. So, the treatments indicated above can be employed in pasture construction and rangeland improvement by planting T. repens as a monoculture or in combination with grasses.