The effect of pruning on forage yield and vitality of Atriplex canescens species in saline habitats of Meyghan playa, Arak, Iran

Atriplex canescens James is one of the successful non-native species in improving and rehabilitating the desert rangelands of Markazi province, which has been cultivated in a large area of saline habitats along the Meyghan playa (about 12,000 ha) since 1981. This species after a few years of growth becomes woody and the density of green aerial organs, survival and forage production decrease. Increasing forage production, vitality and viability of this plant are the requirements for the management of these habitats and pruning is one of the necessities to achieve this. In this study, pruning and census operations have been carried out in three study sites with an average area of one hectare located in the Meyghan playa for four years to determine the appropriate level or height of pruning. At each site, four levels of pruning, including pruning from the ground and pruning from heights of 20, 40, 60 cm and control (without pruning) have been applied. Each treatment was performed on 16 A.canescens stands with an average diameter of canopy and height of 160 and 115 cm, an average production of 530 g per stand and an average of 34 years of age. Pruning was done in March of the first year of study and vitality, forage yield, height, canopy diameter and survival rate factors were inventory in three years later. Data collected and analysed using two way ANOVA (Sits and treatments) based on completely randomized design. Based on the results, in two sites located in the northern and western regions of Meyghan playa with an approximate number of 400 stands per hectare and an age of 38 years of rangeland planting, pruning treatments from heights of 60, 40, 20 cm and pruning from the ground from A.canescens had more favorable effects in terms of increasing vitality and forage production. On the site located in the southern part of the Meyghan playa, with an approximate number of 350 stands per hectare and an age of 30 years of rangeland planting, pruning from ground surface and pruning treatments from heights of 20, 40, 60 cm respectively have been useful in terms of vitality and forage production. In total, after three years used of pruning from ground surface and pruning treatments from heights of 20, 40 and 60 cm, the average yield of A.canescens respectively were 690, 679, 658 and 818 g per plant rootstock. To improve the characteristics of A.canescens species in terms of positive plant factors such as vitality, survival and forage yield, in Atriplex cultivation areas of the northern and western margins of Meyghan playa with an age of 38 years of rangeland planting, pruning operations from a height of 60 cm and for southern areas of Meyghan playa with an age of 30 years of rangeland planting, pruning from the ground is determined and proposed.