1- Assistant professor of the Department of water engineering, Faculty of Agricultural engineering, Sari University of Agriculture and Natural Resources, Sari, Iran
2- Ph.D. candidate of Agricultural Meteorology, Department of Water Engineering, Faculty of Agricultural Engineering, Sari Agricultural sciences and Natural Resources University, Sari, Iran
3- 3- PhD of Entrepreneurship, Center of Entrepreneurship, Sari University of Agriculture and Natural Resources, Sari, Iran.
2- Ph.D. candidate of Agricultural Meteorology, Department of Water Engineering, Faculty of Agricultural Engineering, Sari Agricultural sciences and Natural Resources University, Sari, Iran
3- 3- PhD of Entrepreneurship, Center of Entrepreneurship, Sari University of Agriculture and Natural Resources, Sari, Iran.
Abstract: (82 Views)
Introduction: Today, human societies face various challenges such as climate change and global warming, environmental degradation, and food security concerns. One of the approaches proposed in recent decades to mitigate the adverse effects of climatic factors and enhance agricultural productivity is the use of shading nets, which create favorable microclimatic conditions and consequently improve plant growth and yield. Therefore, the microclimatic effects of shading nets in soybean cultivation have the potential to increase yield per unit area, leading to higher income levels, improved livelihoods, and enhanced economic prosperity for farmers.
Materials and Methods: To evaluate the microclimatic effects of shading nets on the quantitative and qualitative performance of soybean and farmers’ income, a field experiment was conducted based on a randomized complete block design (RCBD) with three replications at the research farm of Sari Agricultural Sciences and Natural Resources University, located at 53°00′E and 36°33′N. According to the extended De Martonne climatic classification, the study area has a humid temperate climate. The treatments included four shading levels: no shading (control), and nets reducing light transmission by 30%, 50%, and 80%. Surface irrigation was applied, and soil moisture was monitored using a tensiometer. Irrigation was carried out when the soil water content reached 70% (SWC=70). Quantitative traits, including plant height, number of pods per plant, number of seeds per pod, 100-seed weight, biomass, harvest index, and seed yield were measured. For qualitative performance, soluble protein content and seed oil percentage were analyzed. Water productivity was evaluated under three conditions: irrigation water productivity (WPI), irrigation plus precipitation productivity (WPI+P), and evapotranspiration productivity (WPET). The economic performance of shading nets in soybean cultivation was assessed using the indicators NBPD, BPD, and the ratios P/C and B/C.
Results and Discussion: Increasing shading intensity led to a reduction in the number of pods per plant, number of seeds per pod, 100-seed weight, and biomass. The highest mean pod number and seed number per pod were obtained under the 30% shading treatment, while these traits decreased significantly under 50% and 80% shading. The greatest and lowest biomass values were recorded for the 30% and 80% shading treatments, with 5500 and 3800 kg ha⁻¹, respectively. A positive and direct correlation was observed between soybean biomass and grain yield, indicating that reductions in biomass led to significant decreases in grain yield. Conversely, plant height increased with shading intensity, with the tallest plants observed under 80% shading, though this treatment exhibited lower grain yield compared to 30% and 50% shading. The highest harvest index values were recorded under 80% and 50% shading (23.4% and 23.6%, respectively), while the lowest value was found in the control (19.3%). Grain yield under 30% shading increased by about 10% compared with the control (1066.7 kg ha⁻¹), whereas yields under 50% and 80% shading decreased by 9% and 16%, respectively. The highest soluble protein content was observed in the control and 30% shading treatments (41.8 and 41.4 µg g⁻¹, respectively), and the highest oil content (0.93%) occurred under 30% shading. In contrast, the lowest values of both protein and oil content were recorded under 80% shading (32.2 µg g⁻¹ and 0.78%, respectively). Moreover, water productivity indices (WPI, WPI+P, and WPET) were highest under 30% shading, followed by other treatments. Despite reduced irrigation water use under 50% and 80% shading, their water productivity remained lower than that of 30% shading. Economically, the highest NBPD and BPD values were obtained under 30% shading (804,653 and 819,163 million IRR m⁻³, respectively), and the P/C and B/C ratios were also superior in this treatment, while the lowest economic indices were observed in the control.
Conclusion: Different shading intensities significantly affected the quantitative and qualitative traits of soybean. Compared with the control, 30% shading resulted in a notable increase in grain yield and the highest water productivity indices. Economic analysis also confirmed the superiority of 30% shading in terms of profitability and efficiency. Therefore, using 30% shading nets in soybean cultivation can serve as a practical and strategic approach to modifying the crop microclimate, enhancing yield per unit area, increasing farmers’ income, and contributing to sustainable agricultural production.
Materials and Methods: To evaluate the microclimatic effects of shading nets on the quantitative and qualitative performance of soybean and farmers’ income, a field experiment was conducted based on a randomized complete block design (RCBD) with three replications at the research farm of Sari Agricultural Sciences and Natural Resources University, located at 53°00′E and 36°33′N. According to the extended De Martonne climatic classification, the study area has a humid temperate climate. The treatments included four shading levels: no shading (control), and nets reducing light transmission by 30%, 50%, and 80%. Surface irrigation was applied, and soil moisture was monitored using a tensiometer. Irrigation was carried out when the soil water content reached 70% (SWC=70). Quantitative traits, including plant height, number of pods per plant, number of seeds per pod, 100-seed weight, biomass, harvest index, and seed yield were measured. For qualitative performance, soluble protein content and seed oil percentage were analyzed. Water productivity was evaluated under three conditions: irrigation water productivity (WPI), irrigation plus precipitation productivity (WPI+P), and evapotranspiration productivity (WPET). The economic performance of shading nets in soybean cultivation was assessed using the indicators NBPD, BPD, and the ratios P/C and B/C.
Results and Discussion: Increasing shading intensity led to a reduction in the number of pods per plant, number of seeds per pod, 100-seed weight, and biomass. The highest mean pod number and seed number per pod were obtained under the 30% shading treatment, while these traits decreased significantly under 50% and 80% shading. The greatest and lowest biomass values were recorded for the 30% and 80% shading treatments, with 5500 and 3800 kg ha⁻¹, respectively. A positive and direct correlation was observed between soybean biomass and grain yield, indicating that reductions in biomass led to significant decreases in grain yield. Conversely, plant height increased with shading intensity, with the tallest plants observed under 80% shading, though this treatment exhibited lower grain yield compared to 30% and 50% shading. The highest harvest index values were recorded under 80% and 50% shading (23.4% and 23.6%, respectively), while the lowest value was found in the control (19.3%). Grain yield under 30% shading increased by about 10% compared with the control (1066.7 kg ha⁻¹), whereas yields under 50% and 80% shading decreased by 9% and 16%, respectively. The highest soluble protein content was observed in the control and 30% shading treatments (41.8 and 41.4 µg g⁻¹, respectively), and the highest oil content (0.93%) occurred under 30% shading. In contrast, the lowest values of both protein and oil content were recorded under 80% shading (32.2 µg g⁻¹ and 0.78%, respectively). Moreover, water productivity indices (WPI, WPI+P, and WPET) were highest under 30% shading, followed by other treatments. Despite reduced irrigation water use under 50% and 80% shading, their water productivity remained lower than that of 30% shading. Economically, the highest NBPD and BPD values were obtained under 30% shading (804,653 and 819,163 million IRR m⁻³, respectively), and the P/C and B/C ratios were also superior in this treatment, while the lowest economic indices were observed in the control.
Conclusion: Different shading intensities significantly affected the quantitative and qualitative traits of soybean. Compared with the control, 30% shading resulted in a notable increase in grain yield and the highest water productivity indices. Economic analysis also confirmed the superiority of 30% shading in terms of profitability and efficiency. Therefore, using 30% shading nets in soybean cultivation can serve as a practical and strategic approach to modifying the crop microclimate, enhancing yield per unit area, increasing farmers’ income, and contributing to sustainable agricultural production.
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