The effect of Pistachio-PAM and Pistachio-PVAc mixed mulches on vegetative parameters and nutritional status of Haloxylon persicum

Considering the high costs of controlling wind erosion and the difficulty of working conditions, choosing basic and technical methods to stabilize these areas, in addition to increasing work efficiency, will also be effective in reducing costs. The first priority and the most effective method of controlling wind erosion is to cover the ground with vegetation, and the more the amount of vegetation, the more effective its role will be. If it is not possible to implement biological plans, mechanical and chemical methods such as mulching should be used. Usually, the main purpose of using mulch in quicksand stabilization activities is to increase the stability of the soil surface against wind erosion in order to create a period during which there is a suitable opportunity to carry out and establish other biological activities of sand stabilization such as planting, sowing seeds, cuttings, etc., and these biological materials can be established in the desired field. In this regard, this research was carried out with the main purpose of investigating the effect of two combined mulches, Pistachio-PAM and Pistachio-PVAC, on the growth and development and nutrition of the Haloxylon persicum.

Pistachio-PAM and Pistachio-PVAC mulches are new hybrid mulches that combine an optimal ratio of pistachio harvest residues and polyacrylamide (PAM) and polyvinyl acetate (PVAc) water-soluble polymers extracted from these wastes and water has been obtained. In this study, the establishment, growth and development of the Haloxylon plant under the conditions of applying Pistachio-PAM and Pistachio-PVAC mulches and the conditions without mulch spraying (control sample) were investigated in four replications. The effect of treatments on the growth and development of Haloxylon was determined after a period of 4 months and afterward, the plants were cut from the crown and the shoot and root parts were separated. Then, shoot and root dry weights were determined and the concentrations of nitrogen, phosphorus, potassium, iron, zinc, copper, and manganese in roots and shoots of the plants were measured separately. Finally, statistical analysis was performed using Minitab 14 software in the form of a completely random design, and the average repetitions were compared with MSTATC software in the form of Duncan's multi-range test.

The results showed that utilization of both mulches caused a significant increase in the shoot and root dry weights and also nutrient concentrations and their absorption by the plants. Furthermore, the presence of the investigated mulches increased significantly the root concentration of elements such as nitrogen, potassium, and manganese, where an increase of almost 250 % in the potassium concentration was observed. Also, both mulch treatments increased significantly the shoot dry weight, N and K concentrations in Haloxylon shoots and an increase of almost 150 % in the shoot dry weight was achieved in the plants treated with the mulch compared to the control.

The increase in vegetative growth in plants and the consequent increase in the concentration and absorption of elements in plants can be discussed in several aspects. Preventing the evaporation of water in windy sand is one of the factors that can be effective in increasing the vegetative and nutritional characteristics of the plant. The presence of a layer with large pores filled with air on the surface of the soil can act as thermal insulation and prevent the transfer of heat to the bottom layers of the pot and water evaporation. The use of two combined mulches, Pistachio-PAM and Pistachio-PVAC, had an effective role in plant water relations, vegetative growth, and improving the nutrition of the plant. Considering that, in order to increase the effectiveness of mulching areas sensitive to erosion or fine dust production, resistant plants suitable for biological control are usually cultivated. Therefore, it seems that the use of Pistachio-PAM and Pistachio-PVAC mulches can play an effective role in improving the growth of Haloxylon plants and it is possible to use the mulching-crown cultivation system in sand fields to stabilize flowing sands, control wind erosion and produce fine dust.