Improving Water Use Efficiency and Economic Benefits of Cropping System through Intercropping in an Arid Climate

The sustainable increase of total productivity by improving resources use efficiency in arid agricultural farming areas is crucial, and intercropping may be a good practice to be implemented in these arid regions. For this purpose, a three-year field experiment was conducted as a randomized complete block design (RCBD) with three replications at the research farm of the Agricultural and Natural Resources Research Station of Gonabad, Gonabad, Iran to assess the agronomic and economic indices of intercropping patterns. The experiment treatments included C1: sole cotton, C2: sole sesame, and intercropping ratios (C3: 20:80, C4: 40:60, C5: 50:50, C6: 60:40, and C7: 80:20 cotton-sesame ratio). The results showed that the leaf chlorophyll content and leaf area index were significantly higher in the intercropped plants compared to the sole cropped plants. The yield components of both crops (such as branches per plant, capsules per plant, seeds per capsule, and 1000-seed weight for sesame, and opened bolls per plant, closed boll per plant, and seed cotton per boll for cotton) significantly improved under intercropping. However, the highest sesame seed yield (2703, 1979, and 1358 kg ha-1, respectively) and seed cotton yield (3749, 2179, and 3426 kg ha-1, respectively) in the three experiment years were observed in the sole cropping treatment. The implementation of intercropping significantly improved the water use efficiency of the cropping system, so that the highest values in the first to third year (0.67, 0.51, and 0.41 kg m-3, respectively) were recorded in the C4, C3, and C7 treatments. The intercropping evaluation indices revealed the advantage of intercropping compared to the sole cropping. The highest value of the land equivalent ration in the first year (1.28) belonged to the C4 treatment, while in the second and third years, belonged to the C7 treatment (1.40 and 1.10, respectively). The calculation of the aggressivity index revealed that in most of the intercropping patterns, especially in the first and second years, cotton showed greater competitive ability than sesame. The highest actual yield loss value in the first year (0.64) belonged to the C3 treatment, while in the second and third years, belonged to the C7 treatment (1.42 and 0.34, respectively). The highest economic advantage in terms of the monetary advantage index in the first year was obtained by the C4 treatment (1140.5), and in the second and third years, was observed in the C7 treatment (940.6 and 265.5, respectively). The intercropping advantage index in the three experiment years was highest (1.41, 3.38, and 0.80, respectively) for the C7 treatment. Eventually, the results of this research show that cotton and sesame are able to adapt well to the intercropping and this cropping system can significantly improve the resources use efficiency (especially water and land) in an arid area enjoying greater economic benefit than sole cropping