عنوان مقاله [English]
Drought is a natural phenomenon in arid and semi-arid regions of the world. It is created by low precipitation, high evaporation and reduced soil moisture. Today, they are the major threats to agricultural lands due to fluctuations in rainfall, limited water resources, wells salinization and subsequently abandoned farming lands. Iran is located on the world's dry belt and more than 90 percent of its area is located in the arid and semi-arid climatic regions. It has been reported that the annual rate of soil erosion is up to 33 tons per hectare and 5 to 6 times more than the standard limit. Also, 90% of the country's protein production comes from animals sources. Due to the lack of adequate forage production, the main burden of protein production is imposed on the natural resources and pastures. Therefore, In order to enhance soil stabilization and maintain its fertility, optimum use of off-season precipitations, preventing the flow of water and protecting the abandoned farming lands from the flood risk, increasing the water permeability in the soil, and helping to feed the underwater aquifers and finally the production of forage and seeds, the development of perennial plants cultivation is an important conservative practice. The aim of this study is to emphasize on the selection of the best perennial forage species with low water requirements and acceptable performance for renovation of the abandoned farming lands and moving towards sustainable agriculture approaches.
Materials and Methods
In this experiment, 10 species of perennial grasses (Agropyron elongatum Host., Secale montanum Guss., Festuca arundinaceae Schreb., Dactylis glomerata L., Agropyron intermedium Host., Agropyron repense L., Agropyron cristatum L., Panicum antidutale Retz., Bromus inermis Leyss., Bromus riparius Rehmann, Agropyron cristatum L.) and two legumes includes Trifolium pratense L., Onobrychis sativa Lam. were studied at Asatan-e-Ghods Razavi farm in Mashhad from 2013 to 2014. The seeds were sown in early November and well-watered for twice after planting and then irrigated by the end of rainfall from May to August, every 22 days.The harvesting time was late August.
Results and Discussion
The results showed that in the first year, the average of seedling establishment was 71% for all species with the lowest 13% for P. antidutale Retz. and the highest 99% for S. montanum Guss. Also, in the years 2013 and 2014 the average of dry forage yield were 1432 and 3663 kg.ha-1, respectively. In the second year, the highest dry forage yield among the species belonged to A. elongatum Host.and B. inermis Leyss. with 10584 and 4029 kg.ha-1, respectively. Also, the grain yield of perennial grasses varied between 185 for A. elongatum Host. to 1085 kg.ha-1for A. cristatum L. In the studied species harvest index was between 2 and 34%. In the first year of perennial species growth, emergence and seedling establishment are one of the most important factors affecting on the increasing seed yield and forage yield. Also, the grain yield was affected by the high number of fertile tillers or stem per plant and number of grains per spike. Another remarkable point was that some grasses showed good seed germination and seedling vigor after immediately harvesting time. The highest seed germination percentage for S. montanum Guss., A. elongatum Host., B. inermis Leyss., A. cristatum L. and B. riparius Rehmann were 96%, 90%, 58%, 55% and 40%, respectively.
The results suggest that the yield of perennial species in the first year was very low and weak to compete with weeds (except S. montanum Guss.). But in the second year, dry forage yield has increased up to 2 or 3 times. Due to limited water resources in Iran, area of abandoned lands (low yield) is increasing. Therefore, the selection of Agropyron genera as a drought tolerant species with the aim of increasing the productivity of the land and to prevent soil erosion and to produce forage or grain yield could be considered.
The authors acknowledge the financial support of the project by Mazra-e-Nemoneh of Astan Ghodes.