Agronomic and Economic Evaluation of Intercropping Systems of Barley (Hordeum vulgare) with Two Medicinal Plants, Fenugreek (Trigonella foenum-graecum) and Garlic (Allium sativum)

Today, agriculture faced various challenges, such as the inadequate of agricultural products for growing human needs, in the other words, step down of food security, reduction of productivity, economic justification, the competitiveness of agriculture, etc. On the other hand, the excessive use of agricultural inputs, especially water, fertilizers and pesticides, excessive pressure on natural resources along with the consequences of climate change has affected the sustainability and stability of agroecosystems. Intercropping as the agricultural practice of growing two or more species in the same farm at the same time has been emphasized by many researchers around the world as one of the ecological approaches for crop production as an effective technique for achieving sustainable agricultural goals. Therefore, the objective of this research was to agronomic and economic evaluation of intercropping patterns of three different crops.

To comparing sole cropping and intercropping systems of barley, fenugreek and garlic, a field experiment was conducted in 2016-17 at the Research Farm of Gonabad University based on a randomized complete block design with three replications. Experimental treatments consisted of sole cropping of barley, fenugreek and garlic; and 4 replacement intercropping series as barley + fenugreek, barley + garlic, fenugreek + garlic, and barley + fenugreek + garlic. Studied traits included of dry forage yield, plant height, 1000-seed weight, biological yield, seed yield, and harvest index in barley, dry forage yield, plant height, pod number per plant, seed number per pod, 1000-seed weight, and seed yield in fenugreek, plant height, leaf number per plant, clove length, clove diameter, clove number per plant, and bulb yield of garlic. In this research, intercropping advantage indexes included land equivalent ratio (LER), actual yield loss (AYL), system productivity index (SPI), intercropping advantage (IA) and relative value total (RVT) were calculated. Analyses of variance were carried out at P≤0.05, using SAS 9.1 software. The means were compared using the Duncan's multiple range test.

The results indicated that the highest values of dry forage yield (8523 kg.ha-1), seed yield (3494 kg.ha-1) and biological yield (14111 kg.ha-1) of barley were achieved from the sole cropping system. Among intercropping treatments, the highest dry forage yield (6109 kg.ha-1) achieved from barley + fenugreek. While, the highest seed yield (2709 kg.ha-1) and biological yield (11081 kg.ha-1) obtained from barley + garlic intercropping. There was no significant difference between sole cropping and intercropping systems about yield components as the plant height, 1000-seed weight, and harvest index of barley. The plant height, number of pod per plant and number of seed per pod showed the highest value in sole cropping system, although there was no significant difference between sole cropping with fenugreek + garlic intercropping. The seed yield (1145 kg.ha-1) and dry forage yield (5100 kg.ha-1) of fenugreek in sole cropping were significantly higher than intercropping patterns. The garlic +fenugreek intercropping treatment with 4090 kg.ha-1 dry forage yield, and 569 kg.ha-1 seed yield had the highest values among intercropping patterns. Yield components of garlic included the plant height, number of leaf per plant, clove length and diameter, and number of clove in plant had the highest value in sole cropping however, there was no significant difference between sole cropping and fenugreek + garlic intercropping. The highest value of bulb yield (7194 kg.ha-1) was obtained from sole cropping and garlic + fenugreek intercropping with the value of 3381 kg.ha-1 ranked in second place. Among intercropping advantage indexes, the highest value of land equivalent ratio (1.16), actual yield increase (0.30), and system productivity (8414) achieved from barley + garlic intercropping system. The highest value of intercropping advantage (0.02) and relative value total (1.27) obtained from fenugreek + garlic and barley + fenugreek, respectively.

According to our findings, intercropping systems of barley + fenugreek and fenugreek + garlic can be selected as an appropriate approach for planting these crops to producing more forage than sole cropping. The results also indicate the better utilization of barley from intercropping advantages than other species and its competitive superiority in the use of environmental resources and economic yield enhancement. Based on the findings of this research, intercropping of barley with garlic and fenugreek is an appropriate approach for increase of land use efficiency and economic profitability that in overall, among cropping systems, barley-garlic intercropping system had more advantage.