Forest and Wood Products

Forest and Wood Products

Evaluation of performance and economic viability of the intercropping of garden Thymus vulgaris with Populus nigra in Markazi Province

Articles in Press

Document Type : Research Paper

Authors
Zahra Ahmadloo 1
Bita Rahimi Badr 1
Roya Eshraghi Samani 1
vilma Bayramzadeh 2
Fatemeh Ahmadloo 3
1 Department of Agricultural Economics Ka.C., Islamic Azad University, Karaj, Iran.
2 Department of Wood and Paper, Ka.C., Islamic Azad University,Karaj, Iran.
3 Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran.
10.22059/jfwp.2026.415236.1394
Abstract
Introduction: Intercropping trees with agricultural crops is considered a modern approach to enhance sustainable land and water productivity while reducing investment risks in wood farming. This applied field study was conducted to evaluate the performance and economic viability of intercropping garden thyme (Thymus vulgaris) with black poplar (Populus nigra '62/154') in Markazi Province, Iran. The primary aim was to improve land and water productivity and to propose a suitable model for sustainable wood farming development in semi-arid regions.
Method: The experiment was carried out on a 1500 m² field in the Abbasabad region of Shazand County, Markazi Province, over a five-year period from 2020 to 2024. The study area has a semi-arid climate with an average annual rainfall of 570 mm and a mean annual temperature of 12°C, providing suitable conditions for agroforestry systems. The statistical design was a randomized complete block design (RCBD) with three treatments (pure poplar, pure thyme, and poplar-thyme intercropping) and three replications. In March 2020, 120 one-year-old poplar saplings were planted at a density of 1250 trees ha⁻¹ (4 × 2 m spacing). In autumn 2021, thyme seedlings were transplanted between poplar rows at densities of 20 plants m⁻² (pure cultivation, 25×20 cm spacing) and 10 plants m⁻² (intercropping, 50×20 cm spacing). Irrigation was applied weekly using a drip irrigation system. Poplar growth traits (diameter at breast height, height, and volume) were recorded over five years, while thyme traits (plant height, branch number, canopy diameter, fresh and dry weight, fresh and dry yield) were measured over three harvest years (2022–2024). Thymus vulgaris Dry weight was determined using an oven at 75°C for 48 hours. Data were analyzed using an independent T-test, two-way ANOVA, and Duncan's multiple range test at the 5% significance level. System efficiency was evaluated using Land Equivalent Ratio (LER), Relative Value Total (RVT), Actual Yield Loss/Gain (AYL), and Intercropping Advantage (IA) indices. Additionally, a linear programming model was designed and solved to optimize net profit under constraints of water, land, and labor resources.
Results: After five years, mean DBH (12.07 cm), height (8.78 m), and total volume (63.46 m³ ha⁻¹) of poplar trees in the intercropping system were significantly higher (P<0.05) than those in pure poplar cultivation (10.33 cm, 7.81 m, and 42.89 m³ ha⁻¹). The current annual volume increment in intercropping (29.90 m³ ha⁻¹) was 39% higher than in pure cultivation. Annual dry thyme yield was significantly higher in pure cultivation (3765 kg ha⁻¹) than in intercropping (3027 kg ha⁻¹). However, the LER and RVT indices (both >1) and the positive IA values confirmed the economic superiority of the intercropping system. The five-year net profit from intercropping was estimated at 65,120 million IRR ha⁻¹. Moreover, the intercropping system reduced water consumption by 26% compared to pure thyme cultivation and increased economic water productivity (based on gross income per cubic meter of water) by more than 2.6 times compared to pure poplar cultivation. Survival rates for both poplar trees and thyme plants were 100% across all treatments.
Conclusion: The poplar-thyme intercropping system is recommended as a superior model for semi-arid regions. This system not only reduces pressure on natural forests and improves water and land productivity, but also generates positive cash flow from the second year (through thyme harvesting), thereby significantly lowering the long-term investment risks associated with wood farming. The results of this study provide a scientific basis for policy-making to promote intercropping systems in similar climatic zones.
Subjects
[1] Ahmadloo, F., Calagari, M., Salehi, A. & Eskandari, S. )2022(. Evaluation of economic productivity of poplar in combination with agricultural, fodder, and medicinal crops. Journal of Iran Nature, 7(2), 35-48.  (In Persian) https://doi.org/10.22092/irn.2022.126676
[2] Goodarzi, Gh. & Ahmadloo, F. )2019(. Introducing suitable cultivars in poplar research in Markazi province. Journal of Iran Nature, 4(3), 27-35. (In Persian)
[3] Calagari, M., Ghasemi, R., Asadi,  F. & Baghery, R. )2018(. Promotion of wood production of some poplar clones using sprouts management in Karaj. Iranian Journal of Forest, 10 (1), 79-88. [In Persian]
[4] Ghasemi Pirbalouti, A., Emami Bistghani, F. )2015(. An overview on genus Thymus. Journal of Herbal Drugs, 6 (2), 93-100. (In Persian)
[5] Mcgimpsey, J.A., Douglas, M.H.D., VanKlink, J.W, Beauregard, D.A. & Perry, N.B. )1994(. Seasonal Variation in essential oil yield and composition from naturalized Thymus Vulgaris in New Zealand . Flavour and Fragrance, 9, 347-352.
[6] Azimi, M., Naqdi Badi, H., Kalateh Jari, S., Abdousi, V. & Mehrafarin, A. )2014(. Comparison of chemical compositions of essential oils of thyme populations (Thymus daenensis, T. fallax and T. vulgaris). Iran. Medicinal Plants, 13(52), 136-146. (In Persian)
[7] Ahmadloo, F. & Eskandari, S. )2023(. Performance evaluation and usefulness indices of agroforestry cultivation of Eurasian poplar and alfalfa in Karaj conditions. Journal of Crop and Horticultural Production and Processing, 13(4), 63-76. (In Persian)
[8]Ahmadloo, F. & Eskandari, S. )2023(. Evaluation of yield, yield components and usefulness indices of intercropping of Eurasian poplar with garlic under Karaj conditions. Journal of Sustainable Agricultural Sciences Research, 3(2), 15-34. (In Persian)
[9]Asadi, F., Kalagri, M. )2019(. Benefits of intercropping poplar with crops and forage crops. Hyrcanian Forest Conservation and Utilization Extension Journal, 1(1), 5-16. (In Persian)
[10] Nazari, M., Abbasi-Soraki, A. & Fallah, S. )2017(. Studying the effect of agroforestry systems and conventional cultivation on yield and yield components of wheat (Triticum aestivam L.) and barley (Hordeum vulgare L.). Journal of Agricultural Ecology, 9(1), 198-216. (In Persian)
[11] Asadi, F. & Khodakarimi, A. )2016(. Intercropping of Populus alba and alfalfa in West Azerbaijan. Iran Forest Journal, 8(1), 51-65. (In Persian)
[12] Latifi, A., Ramyar, H. & Naseri, F. )2015(. Investigating the impact of agroforestry systems on sustainable agricultural development. First National Specialized Conference on Agricultural and Environmental Sciences of Iran, pp. 1-9. (In Persian)
[13] Sadati, S.A. & Asadi, F. )2011(. Introducing the intercropping of poplar with wheat in the plains of Mazandaran. Journal of Hyrcanian Forest Conservation and Utilization, 3(1), 27-38. (In Persian)
[14] Dash, U., Gupta, B., Bhardwaj, D.R., Sharma, P., Kumar, D., Chauhan, A., Keprate, A. & Das, J. )2024(. Tree spacings and nutrient sources effect on turmeric yield, quality, bio-economics and soil fertility in a poplar-based agroforestry system in Indian Himalayas. Agroforestry Systems, 98(2), 911-931. https://doi.org/10.1007/s10457-024-00962-3.
[15] Dahiya, G., Bhardwaj, K.K., Devi, S., Ahlawat, I., Singh, C. & Dhillon, R.S. )2022(. Influence of different agroforestry systems on crop yield and nutrient uptake in semi-arid region of Haryana. Indian Journal of Agroforestry, 24(2), 19-23.
[16] Piotto, S., Panozzo, A., Pasqualotto, G., Carraro, V., Barion, G., Mezzalira, G., Furlan, L., Sterup Moore, S. & Vamerali, T. )2024(. Phenology and radial growth of poplars in wide alley agroforestry systems and the effect on yield of annual intercrops in the first four years of tree age. Agriculture, Ecosystems & Environment, 361, 108814. https://doi.org/10.1016/j.agee.2023.108814
[17] Raisi, M., Peikarestan, B., Madani, H. & Farahvash, F. )2014.( Effects of different levels of biofertilizers on thyme plant performance in Arak city. First International Congress and 13th National Congress of Agricultural Sciences and Plant Breeding and Third Conference on Seed Science and Technology, Institute for Seed and Seedling Breeding and Production Research, Karaj. Iran: pp. 1-5. (In Persian)
[18]Amighi, S.J., Askari, H.R. & Vahed, B.S. )2013(. The effect of agroforestry system on soil surface layer properties (case study of Biarjomand region - Semnan province). Crop Ecology, 9(3),1-8. (In Persian)
[19] Zohraby, A., Atamidi, A., Safari, H. & Jafari, A.A. )2011(. Investigating the sustainability of forage yield in accessions of the species Elymus hispidus using the AMMI model and other sustainability analysis methods in two stress and non-stress environments. Rangeland, 5 (2), 209-218. (In Persian)
[20] Chandra, J.P. )2011(. Development of poplar-based agroforestry system. Indian Journal of Ecology, 38, 11-14.
[21] Calagari, M., Ghasemi, R., Asadi,  F. & Baghery, R. )2018(. Promotion of wood production of some poplar clones using sprouts management in Karaj. Iranian Journal of Forest, 10(1), 79-88. (In Persian)
[22] Emam, Y., Hosseini, A., Rafiee, N. & Pirasteh Anosheh, H. )2013(. Response of early growth and sodium and potassium ions concentrations in ten barley (Hordeum vulgare L.) cultivars in salinity tension conditions. Crop Physiology Journal, 5(19), 5-15. (In Persian)
[23]Ahmadloo, F., Ghasemi, R., Kalagari, M. & Salehi, A.)2019(. Phenomenological and vegetative and morphological characteristics of eight black poplar (Populus nigra L.) clones at Alborz Karaj Research Station. Iranian Forest and Poplar Research, 28(1), 30-43. (In Persian)
[24] Goodarzi, Gh. & Ahmadloo, F. )2019(. Introducing suitable cultivars in poplar research in Markazi province. Journal of Iran Nature, 4(3), 27-35. (In Persian)
[25] Calagari, M., Ghasemi, R., Asadi,  F. & Baghery, R. )2018(. Promotion of wood production of some poplar clones using sprouts management in Karaj. Iranian Journal of Forest, 10(1), 79-88. (In Persian)
[26] Emam, Y., Hosseini, A., Rafiee, N. & Pirasteh Anosheh, H. )2013(. Response of early growth and sodium and potassium ions concentrations in ten barley (Hordeum vulgare L.) cultivars in salinity tension conditions. Crop Physiology Journal, 5(19), 5-15. (In Persian)
[27]Ahmadloo, F., Ghasemi, R., Kalagari, M. & Salehi, A.)2019(. Phenomenological and vegetative and morphological characteristics of eight black poplar (Populus nigra L.) clones at Alborz Karaj Research Station. Iranian Forest and Poplar Research, 28(1), 30-43. (In Persian)
[28] Emam, Y., Hosseini, A., Rafiee, N. & Pirasteh Anosheh, H. )2013(. Response of early growth and sodium and potassium ions concentrations in ten barley (Hordeum vulgare L.) cultivars in salinity tension conditions. Crop Physiology Journal, 5(19), 5-15. (In Persian)
[29] Vandermeer, J.H. )1990(. Intercropping, In C.R. Carroll, J.H. Vandermeer and P. Rosset (Eds.), Agroecology. McGraw– Hill publishing Co., New York, pp. 481-516.
[30] Lithourgidis, A.S., Vlachostergios, D.N., Dordas, C.A. & Damalas, C.A. )2011(. Dry matter yield, nitrogen content, and competition in pea-cereal intercropping systems. European Journal of Agronomy, 34, 287-294.
[31]Ahmadloo, F. & Eskandari, S. )2023(. Evaluation of yield, yield components and usefulness indices of intercropping of Eurasian poplar with garlic under Karaj conditions. Journal of Sustainable Agricultural Sciences Research, 3(2), 15-34. (In Persian)
[32]Asadi, F. &Kalagri, M. )2019(. Benefits of intercropping poplar with crops and forage crops. Hyrcanian Forest Conservation and Utilization Extension Journal, 1 (1), 5-16. (In Persian)
[33] Nazari, M., Abbasi-Soraki, A. & Fallah, S. )2017(. Studying the effect of agroforestry systems and conventional cultivation on yield and yield components of wheat (Triticum aestivam L.) and barley (Hordeum vulgare L.). Journal of Agricultural Ecology, 9(1), 198-216. (In Persian)
[34] Asadi, F., & Khodakarimi, A. )2016(. Intercropping of Populus alba and alfalfa in West Azerbaijan. Iran Forest Journal, 8(1), 51-65. (In Persian)
[35] Latifi, A., Ramyar, H. & Naseri, F. )2015(. Investigating the impact of agroforestry systems on sustainable agricultural development. First National Specialized Conference on Agricultural and Environmental Sciences of Iran, pp. 1-9. (In Persian)
[36] Ahmadloo, F. & Eskandari, S. )2023(. Evaluation of yield, yield components and usefulness indices of intercropping of Eurasian poplar with garlic under Karaj conditions. Journal of Sustainable Agricultural Sciences Research, 3(2), 15-34. (In Persian)
[37] Sadeghi, A., Salehi, A., & Mousavi Cooper, S.A. )2015(. The effect of pure and mixed planting of poplar and peanut on soil chemical properties (Case study: Fakhrabad Lasht-Nasha Agricultural Research Station). Journal of Iran Forest Ecology, 3(6), 28-35. [In Persian]
[38] Salehi, A., Ghorbanzadeh, N. & Kahneh, E. )2020(. Soil microbial biomass, enzyme activity and nutrient cycling in a poplar (Populus nigra)-thyme (Thymus vulgaris) agroforestry system under semi-arid conditions. Agroforestry Systems, 94(4), 1525-1538.
[39] Piotto, S., Panozzo, A., Pasqualotto, G., Carraro, V., Barion, G., Mezzalira, G., Furlan, L., Sterup Moore, S. & Vamerali, T. )2024(. Phenology and radial growth of poplars in wide alley agroforestry systems and the effect on yield of annual intercrops in the first four years of tree age. Agriculture, Ecosystems & Environment, 361, 108814. https://doi.org/10.1016/j.agee.2023.108814
[40] Vandermeer, J.H. )1990(. Intercropping, In C.R. Carroll, J.H. Vandermeer and P. Rosset (Eds.), Agroecology. McGraw– Hill publishing Co., New York, pp. 481-516.
[41] Mcgimpsey, J.A., Douglas, M.H.D., VanKlink, J.W, Beauregard, D.A. & Perry, N.B. )1994(. Seasonal Variation in essential oil yield and composition from naturalized Thymus vulgaris in New Zealand . Flavour and Fragrance, 9, 347-352.
[42] Raisi, M., Peikarestan, B., Madani, H. & Farahvash, F. )2014.( Effects of different levels of biofertilizers on thyme plant performance in Arak city. First International Congress and 13th National Congress of Agricultural Sciences and Plant Breeding and Third Conference on Seed Science and Technology, Institute for Seed and Seedling Breeding and Production Research, Karaj. Iran: pp. 1-5. (In Persian)
 [43] Yang, T., Zhu, Y., Duan, Z.P., Lu, W.H., Zhang, F.F., Wan, S.M., Xu, W.X., Zhang, W. & Li, L.H. )2020(. Root distribution and productivity in a poplar tree + alfalfa silvopastoral system in northwest China’s Xinjiang Province. Agroforestry Systems, 94(3), 997-1010. https://doi.org/10.1007/s10457-019-00466-5
[44] Dai, Y.S., Yang, T., Shen, L., Wang, X.Y., Zhang, W.L., Liu, T.T., Lu, W.H., Li, L.H. & Zhang, W. )2021(. Root growth, distribution, and physiological characteristics of alfalfa in a poplar/alfalfa silvopastoral system compared to sole-cropping in northwest Xinjiang, China. Agroforestry Systems, 95 (2), 1137-1153. https://doi.org/10.1007/s10457-021-00639-1
[45] Chauhan, S.K., Dhillon, W.S., Singh, N. & Sharma, R. )2013(. Physiological behavior and yield evaluation of agronomic crops under agri-horti-silviculture system. International Journal of Plant Research, 3(1), 1-8.
[46] Seserman, D.M., Veste, M., Freese, D., Swieter, A. & Langhof, M. )2018(. Benefits of agroforestry systems for land equivalent ratio-case studies in Brandenburg and Lower Saxony, Germany. In Proceedings of the 4th European Agroforestry Conference-Agroforestry as Sustainable Land Use, Nijmegen, The Netherlands, 28–30 May 2018, 26-29.
[47] Zheng, W., Li, Y., Gong, Q., Zhang, H., Zhao, Z., Zheng, Z., Zhai, B. & Wang, Z. )2016(. Improving yield and water use efficiency of apple trees through intercrop-mulch of crown vetch (Coronilla varia L.) combined with different fertilizer treatments in the Loess Plateau. Spanish Journal of Agricultural Research, 14(4), e1207.
[48] Chavan, S.B., Dhillon, R.S., Sirohi, C., Keerthika, A., Kumari, S., Bharadwaj, K.K., Jinger, D., Kakade, V., Chichaghare, A.R., Zin El-Abedin, T.K., Mahmoud, E.A., Casini, R., Sharma, H., Elansary, H.O. & Yessoufou, K. )2022(. Enhancing farm income through boundary plantation of poplar (Populus deltoides): An economic analysis. Sustainability, 14(4), 8663. https://doi.org/10.3390/su14148663
[49]Asadi, F., Kalagri, M. )2019(. Benefits of intercropping poplar with crops and forage crops. Hyrcanian Forest Conservation and Utilization Extension Journal, 1(1), 5-16. (In Persian)
[50] Dhiman, R.C. (2008). Evolution of poplar- based agroforestry in India. 23rd session of International Poplar Commission. 27-30 October )2008(, Beijing, China, 52 p.
[51] Haque, M. )2014(. Highest wood production by poplar (Populus deltoides) clones under agroforestry systems in Punjab state of India- a case study. Word Congress on Agroforestry, 10-14 Feb, Delhi.
[52] Chauhan, S.K., Dhillon, W.S., Singh, N. & Sharma, R. )2013(. Physiological behavior and yield evaluation of agronomic crops under agri-horti-silviculture system. International Journal of Plant Research, 3(1), 1-8.
[53]Asadi, F. & Kalagri, M. )2019(. Benefits of intercropping poplar with crops and forage crops. Hyrcanian Forest Conservation and Utilization Extension Journal, 1(1), 5-16. (In Persian)
 [54] Tramacere, L.G., Sbrana, M. & Antichi, D. )2023(. N2 use in perennial swards intercropped with young poplars, clone I-214 (Populus × euramericana (Dode) Guinier), in the mediterranean area under rainfed conditions. Agronomy, 13(7), 1761. https://doi.org/10.3390/agronomy13071761.
[55]Ahmadloo, F. & Eskandari, S. )2023(. Evaluation of yield, yield components and usefulness indices of intercropping of Eurasian poplar with garlic under Karaj conditions. Journal of Sustainable Agricultural Sciences Research, 3(2), 15-34. (In Persian)
Forest and Wood Products

Articles in Press, Accepted Manuscript
Available Online from 06 October 2026