نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Introduction
Lentil (Lens culinaris L.) is one of the most important plants in the legume family, which is of great importance in the nutritional system of human societies, especially in developing countries, due to the fact that they contain about 25% protein. In recent years, biofertilizers have received increasing attention as a sustainable alternative to chemical fertilizers, particularly due to the environmental and soil-related problems associated with the excessive use of synthetic inputs. Biofertilizers can improve various soil properties while providing economic, environmental, and social benefits. Consequently, they play an important role in emerging agricultural approaches, including sustainable, organic, and biological farming systems. Biofertilizers encompass a range of biologically derived materials and processes that contribute to soil fertility and plant nutrition. In addition to organic matter derived from animal manure and plant residues, they include beneficial microorganisms involved in processes such as biological nitrogen fixation and the mobilization or increased availability of phosphorus and other essential nutrients in the soil. Through these mechanisms, biofertilizers can enhance nutrient availability, support soil health, and reduce dependence on chemical fertilizers. Legumes are one of the most important plant sources rich in protein and are considered the second most important source of human food after cereals. These plants, by biologically fixing nitrogen, while improving soil fertility as a cover crop or in rotation with some crops, are effective in preventing soil erosion and play an important role in the sustainability of agricultural systems. Legumes are also low-demanding plants in terms of nutrient requirements, which are desirable for cultivation in low-input agricultural systems and are important from an ecological and environmental perspective in preventing land erosion and pollution. Other factors that affect crop production include planting date and cultivar. The choice of planting date is important because it determines the environmental conditions under which the plant will grow and develop. This is especially important for plants such as lentils, which are grown primarily in the spring, relying on soil moisture, and which may expose the plant to high temperatures at the end of the season.
Materials and Methods
This experiment was conducted as a split factorial experiment in a randomized complete block design with three replications in the 2015-2016 crop year at Shahrekord University Research Farm. The experimental treatments included: the main factor of two planting dates (March 15, 1403 and April 15, 1404), the sub-factorial factor of two lentil cultivars (Varzaghan and Bileh-Savar) at five fertilizer levels including the application of rhizobium bacteria (Rizobium leguminosarum); the combined use of rhizobium and nitrogen fertilizer; the use of mycorrhizal fungus (Glomus mosseae); the full application of chemical fertilizers required based on soil analysis; and the control (without fertilizer application). Standard agricultural practices were applied uniformly throughout the growth period.
Results and Discussion
The results showed that the combined treatment of Rhizobium + nitrogen increased most growth and yield traits in both lentil cultivars. This treatment increased plant height, stem diameter, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, number of pods per plant, number of seeds per plant, grain yield, and grain protein content. However, no significant effect was observed on protein yield. Lentils were inoculated with the bacterium Rhizobium leguminosarium, and the lighter the soil, the more significant the effect of seed inoculation with the bacteria on yield. According to studies by the Australian Grains Research Institute (MEAGRE), lentils are capable of fixing about 35 to 75 kg/ha of nitrogen. Mycorrhizal biofertilizer increased the phosphorus content of lentil grain, and it seems that mycorrhizae improve the growth, development and performance of the host plant in sustainable agricultural systems by increasing the absorption of nutrients such as nitrogen and some elements such as phosphorus, and increasing the level of water absorption. The modified variety of Bilesawar had better performance for all the mentioned traits at the planting date of March. From the higher yield of the crop at the planting date of March, it can be inferred that the sensitive vegetative and especially reproductive period of the lentil plant did not encounter high temperatures at the end of the growing season, and this had a positive effect on the podding and grain setting of the lentil plant and ultimately the biological performance of the plant. Therefore, it is recommended to use a combination of biological and chemical fertilizers such as Rhizobium + Nitrogen fertilizer at the desired level and the Bilesawar variety at the planting date of March to improve the morphophysiological characteristics of the lentil plant, not only from chemical fertilizers, but also to achieve sustainable agricultural goals and maintain the physical and chemical properties of the soil.
Conclusions
The findings of this study show that the integrated application of biofertilizers and chemical fertilizers was more effective than the separate application of either type of fertilizer. The excessive use of chemical fertilizers alone has contributed to the deterioration of sustainable and organic agricultural systems in many regions of the world in recent decades. Government policies aimed at achieving high crop yields and increasing farmers’ incomes are among the major factors contributing to the excessive use of chemical fertilizers and the subsequent degradation of soil and the environment. The cultivation of crops such as lentil, which can serve as a cover crop and fix atmospheric nitrogen while contributing to carbon sequestration, can substantially reduce the adverse effects associated with excessive fertilizer use and help address the challenges of cultivation in degraded agricultural soils. In addition, selecting an appropriate, high-quality cultivar and determining the optimal planting date are essential for achieving high crop yields, as inappropriate cultivar selection or planting time can impose substantial costs on farmers and significantly reduce yields.
Acknowledgements
The authors of the article would like to express their gratitude for the support of Shahrekord University, as well as the National Soil and Water Research Center for providing biofertilizers, and the Ardabil Agricultural Jihad Organization for
کلیدواژهها English
Authors retain the copyright. This is an open access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0)
