Evaluation of Water Use Efficiency in Intercropping of Sunflower (Helianthus annuus L.), Cotton (Gossypium spp.) and fodder beet (Beta vulgaris subsp. vulgaris L.) based on the traditional Pattern of planting in Khorasan

IntroductionAt present, farmers are facing problems of shrinking landholding size, degradation of natural resources, climatic vulnerabilities and low financial returns due to escalating cost of cultivation and inefficient utilization of agroinputs. Thus, production per unit area of land, time and inputs needs to be improved by efficiently capturing the solar energy and carbon dioxide for conversion into economic product. In recent years, there has been increased interest in agricultural production systems in order to achieve high productivity and promote sustainability over time. Intercropping as a common method in sustainable agricultural systems, plays an important role in increasing productivity and yield stability to improve utilization of resources. One of the most important benefits of intercropping is increasing production per unit area compared with sole cropping. The reason for increasing the yield in the intercropping is the better use of environmental factors such as water, nutrients and light. The present study was designed to investigate the effects of mixed and row intercropping on yield and yield component of sunflower, cotton and fodder beet.Materials and Methods         In order to study the effects of mixed and row intercropping of cotton, sunflower and fodder beet on yield and yield components in three species, a split-plot experiment based on randomized complete blocks design with three replicates was performed in research farm of Ferdowsi University of Mashhad in 2017-2018. Cropping pattern (mixed or row intercropping) was allocated to the main plots and different planting ratios (50% Cotton +37.5% Sunflower +12.5% fodder beet, 50% Cotton +37.5% fodder beet +12.5% Sunflower, 33.3% Cotton +33.3% Sunflower +33.3% fodder beet, sole cropping of Cotton, sole cropping of Sunflower and sole cropping of fodder beet) were assigned to the sub-plots. Yield and yield component, indices such as Land Equivalent Ratio (LER) and Water Use Efficiency (WUE) were measured. For analyzing data, SAS ver.9.1 was used and mean comparison was performed based on Duncan test.Results and DiscussionThe results indicated that in intercropping of cotton, fodder beet and sunflower and in all plant ratios, the total LER was more than one. The highest LER was obtained in 50% cotton + 37.5% sunflower + 12.5% ​​fodder beet ratio and in both mixed and row intercropping patterns. The lowest LER was observed in ratio of 50% cotton + 37.5% fodder beet + 12.5% ​​sunflower and in mixed intercropping pattern. The highest amount of LER in cotton was obtained in ratio of 50% cotton + 37.5% fodder beet + 12.5% sunflower and in both methods of mixed and row intercroping and in ratio of 50% cotton + 37.5% sunflower + 12.5 % fodder beet was obtained in row intercroping pattern. In 33.3% cotton + 33.3% fodder beet + 33.3% sunflower ratio, cotton had the lowest partial LER in both mix and row intercroping patterns. Among different ratios of cotton planting, sole cropping with 0.32 kg / m3 had the highest and ratio of 33.3% cotton + 33.3% fodder beet + 33.3% sunflower, with 0.13 kg / m3, had the lowest water use efficiency. ConclusionsDue to the different morphology, phenology and growth type of plants used in the present study, it seems that the intercropping of cotton-sunflower and fodder beet can increase the efficiency of using resources, especially water. So intercropping is one of the highly promising approaches for enhancing agricultural productivity and profitability that can provide sustainability in agricultural ecosystem. Intercropping  reduces  the  risk  of  crop  failure, improves  productivity  per  unit  area,  improves  profitability  and can  provide  a  pathway  to  food  security  in  vulnerable  production systems. AcknowledgementsThis research (Grant No. 47291), was funded by Vice Chancellor for Research of the Ferdowsi University of Mashhad, which is hereby acknowledged.