The effects of plant density and irrigation management on forage production of quinoa and forage sorghum

Background and objectives: It is predicted that at least 10 million people will be hungry and malnourished in the world by the end of this century. To reduce the food insecurity, crop production will have to be doubled, and produced in more environmentally sustainable ways. This can be achieved by expanding the area of crop production, increasing per hectare yield and improving crop quality. Furthermore, during the second half of the past century, rise in per hectare crop productivity was due to improved or high yield potential. The productivity of plants are strongly influenced by environmental stresses. In the water scarcity condition, using deficit irrigation and appropriate cultivar are the most strategies to improve water productivity. A new generation of dry-tolerant forage varieties would allow for landscape development in stresses environments and where fresh water is limited or not available for irrigation. Hence, the present study was to design with the following objectives: To determine yield and morphogical parameters of quinoa (Chenopodium quinoa Willd.) and forage sorghum) sorghum bicolor), verities at different levels of irrigation and plant densities.
Materials and methods: A field experiment was conducted during 2015 and 2016 at Aghghala salinity station. The experiment was laid out in a randomized complete block design in form of factorial split plot factorial experiment and replicated four times. At this research effects of irrigation frequency at four levels (irrigation after 5, 10, 15 and 20 days), and plant density at three levels (11.1, 16.7 and 33.3 plants per m2) on quinoa (Santa Maria and Sajama Iranshahr) and verities of KFS3 and Speed feed sorghums were investigated. Sowing date was the time of soil temperature reaching to 12 °C and the harvesting date was the time of 5% flowering of each plot. For yield estimation, after removing borders, 6 m2 harvested. Data were analyzed using SAS. Treatment means were compared using LSD at the 95%probability level.
Results: Results showed that, the difference in most treats between treatments was significant. Investigation of dry forage yield at irrigation treatment showed, irrigation every 5 days interval with dry yield of 6.01 ton ha-1 had the highest yield and yield components of dry forage. With increasing plant density and dicrasing irrigation frequency dry matter dicreased but this dicreasing mostly accurse at interaction affect of irrigation every 20 days interval and plant density of 333000 plant ha-1. Plant density of 11.12 plants per m2 with yield of 4.98 ton ha-1 had the highest yield. The suitable treatment was variety of Santa Maria at 11.1 plants per m2 with dry yield of 4.77 ton ha-1 had the highest dry yield and variety of Speedfeed sorghum at plant density of 33.3 plants per m2 with yield of 2.53 ton ha-1 had the less ranking.
Conclusions: In all, in order to high quantitative yield irrespective of variety, most frequently irrigation had higher yield than less and intermediate irrigation regime. Though, when comparing the four varieties, quinoa (Santa Maria variety (significantly with dry yield of 4.42 ton ha-1 produced higher dry forage yield. The present findings suggest that in semiarid environments (where saving water is important) it seems that incrasing irrigation frequency is effective for good stand establishment in the saline soils could be insured if proper management is applied in the farms.