Evaluation of drought resistance of grass and clover mixtures to introduce cover plants with lower maintenance

Eco-lawn is a mixture of grass and broad leafy plants to create a diverse species composition. In fact, it is low input lawn that requires less watering, fertilizing, herbicide and mowing. It resists to invasion of weeds, which helps conserve natural resources and reduce pollutants.

This experiment was done in greenhouse at Ferdowsi university of Mashhad to explore the effects of water stress (85, 65, 45 and 25 % of FC) on shoot and root reactions of grass-clover mixtures. It was done in a factorial experiment based on randomized complete block design with three replications. Treatments were six mixtures of Festuca arundinacea and micro clover (FM), Lolium perenne and micro clover (LM), Lolium perenne and Trifolium repens (LT), F. arundinacea and L. perenne and micro clover (FLM), F. arundinacea, L. perenne, micro clover and T. repens (FLTM). Traits of height, leaf width, tiller number, fresh and dry weight of shoot and root, root surface, Mean diameter root, total root length, root volume were measured.

The results showed that in the competition between 6 types of mixed grass-clover, the highest and the lowest height were for LT mixed with mean of 5.89 cm and FLTM mixed with average of 5.02 respectively. In terms of fresh and dry weights of shoots, FLTM and LT had the highest and FM had the lowest production weight. Also 65% FC stress had no significant effect on plant height and significant difference was observed at 45 and 25% FC levels. The effect of 25% FC on leaf width and tiller number was significant and 45% FC of stress intensity had no significant effect on fresh and dry weight of aerial parts of grasses. In terms of underground organs, the highest fresh and dry weight of roots belonged to FLTM and LM and then FM. But the lowest fresh and dry weight of roots produced by LT grass with 38.68 and 9.52 gr/ pot respectively. In terms of different levels of drought stress, in mild stress of 65% FC, the amount of fresh and dry weight of roots increased compared to the level of 85% by 20.93% and 9.54%. But in 45% FC stress, drought stress led to a decrease in fresh and dry weight of root production. So that, in severe stress of 25% FC, in compared to 85% stress, the rate of fresh and dry root weight loss was 52.64 and 54.87%, respectively.

It can be concluded that all mixtures except LT were superior in root traits than commercial sport turf (S), while FLTM was the best blended especially for aerial parts traits than others.