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

Abstract

Sustainable increase of total productivity by improvement of resources use efficiency in arid areas is very important. Intercropping can be a good practice for this strategy. For this purpose, a three-year field experiment was conducted as a randomized complete block design (RCBD) with three replications 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). Obtained results showed that the leaf chlorophyll content and leaf area index were significantly higher in the intercropped plants than 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 sole cropping treatment. Implementation of the 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. Intercropping evaluation indices showed the advantage of intercropping compared to 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 was dominant over 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 due to the C4 treatment (1140.5), and in the second and third years, was observed due to 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. In general, the results of this research show the compatibility of cotton and sesame to intercropping system and significant improving the resources use efficiency (especially water and land) under the intercropping in an arid area and its greater economic benefit than sole cropping.