Document Type : Original Articles
Authors
1
Dept. of Agronomy, Faculty of Agriculture, Ilam University, Ilam, Iran
2
garveh amuzeshi daneshgah ilam ,daneshkodeh keshavarzi.garveh zaraat vaslah nabatat
3
Department of Agronomy and Plant Breeding, Faculty of Agriculture, Ilam University, Ilam, Iran
Abstract
Introduction: Cowpea (Vigna unguiculata L.) is one of the major sources of plant protein in arid and semi-arid regions, and its production is highly constrained by drought stress. This stress reduces chlorophyll synthesis, decreases photosynthetic efficiency, and ultimately lowers yield. The use of phosphate-solubilizing biofertilizers in combination with chemical fertilizers can alleviate drought effects by improving root characteristics and enhancing plant defense mechanisms..
Materials and methods: The experiment was conducted during the 2023–2024 growing season in Ivan County, Ilam Province, using a split-plot design based on a randomized complete block design with three replications. The experimental treatments included three irrigation intervals (7, 9, and 12 days) as the main plots and five fertilizer treatments (control, Barvar-2 phosphate biofertilizer, Barvar potassium biofertilizer, phosphorus fertilizer, and potassium fertilizer) as the subplots. Traits measured at physiological maturity included stomatal diameter, stomatal density, stomatal length, number of grains per pod and per plant, number of pods per plant, 100-seed weight, biological yield, grain yield, and harvest index. Data were analyzed using SAS software version 9.4, and mean comparisons were performed with the LSD test at a 5% probability level.
Results and discussion: Results indicated that drought stress caused by longer irrigation intervals (9–12 days) imposed severe physiological constraints on cowpea, manifested as a 40% reduction in stomatal conductance, a 28% reduction in pod formation, and a 32% decline in final grain yield compared with the control (7-day irrigation). Barvar-2 phosphate biofertilizer played a key role in mitigating these effects and was able to maintain 90% of yield potential under mild stress (9-day irrigation). This effect was achieved through three synergistic mechanisms: (1) a 45% increase in phosphorus uptake via microbial solubilization, (2) a 28% increase in root biomass leading to improved water and nutrient absorption, and (3) maintenance of 80% photosynthetic activity during peak stress periods. The combined treatment of 7-day irrigation with Barvar-2 biofertilizer produced the highest yield (1434.95 kg ha⁻¹), which was 22% higher than conventional fertilization and showed greater water-use efficiency. Interestingly, the 9-day irrigation regime combined with biofertilizer provided a dual advantage of 30% irrigation water saving while retaining 90% of the maximum yield.
Conclusions: The present study demonstrated that appropriate nutrient management using Barvar-2 phosphate biofertilizer can serve as an effective strategy to enhance cowpea resilience under water-limited conditions. The findings revealed that integrating irrigation management with biofertilization not only compensates for yield losses caused by drought but also improves water- and nutrient-use efficiency, thereby creating a sustainable basis for cowpea production in arid regions. Importantly, this approach allows higher productivity without additional water consumption, reducing production risks for smallholder farmers. Therefore, the application of biofertilizers alongside optimized irrigation can be recommended as a practical and climate-resilient model for developing legume-based cropping systems under limited water resources.
The present study demonstrated that appropriate nutrient management using Barvar-2 phosphate biofertilizer can serve as an effective strategy to enhance cowpea resilience under water-limited conditions. The findings revealed that integrating irrigation management with biofertilization not only compensates for yield losses caused by drought but also improves water- and nutrient-use efficiency, thereby creating a sustainable basis for cowpea production in arid regions. Importantly, this approach allows higher productivity without additional water consumption, reducing production risks for smallholder farmers. Therefore, the application of biofertilizers alongside optimized irrigation can be recommended as a practical and climate-resilient model for developing legume-based cropping systems under limited water resources.
The present study demonstrated that appropriate nutrient management using Barvar-2 phosphate biofertilizer can serve as an effective strategy to enhance cowpea resilience under water-limited conditions. The findings revealed that integrating irrigation management with biofertilization not only compensates for yield losses caused by drought but also improves water- and nutrient-use efficiency, thereby creating a sustainable basis for cowpea production in arid regions. Importantly, this approach allows higher productivity without additional water consumption, reducing production risks for smallholder farmers. Therefore, the application of biofertilizers alongside optimized irrigation can be recommended as a practical and climate-resilient model for developing legume-based cropping systems under limited water resources.
The present study demonstrated that appropriate nutrient management using Barvar-2 phosphate biofertilizer can serve as an effective strategy to enhance cowpea resilience under water-limited conditions. The findings revealed that integrating irrigation management with biofertilization not only compensates for yield losses caused by drought but also improves water- and nutrient-use efficiency, thereby creating a sustainable basis for cowpea production in arid regions. Importantly, this approach allows higher productivity without additional water consumption, reducing production risks for smallholder farmers. Therefore, the application of biofertilizers alongside optimized irrigation can be recommended as a practical and climate-resilient model for developing legume-based cropping systems under limited water resources.
Keywords: Barvar-2 phosphate, Biological yield, Harvest index, Irrigation interval, Stomata
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