نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Introduction
Lentils are 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. Today, the use of biofertilizers has received more attention than ever before due to the problems caused by the excessive use of chemical fertilizers. The use of such fertilizers has positive effects on all soil properties. It is also beneficial from economic, environmental and social aspects and can be a suitable and desirable alternative to chemical fertilizers. Currently, new approaches to agriculture, such as sustainable organic and biological agriculture, are based on the exploitation of such resources. In addition to organic matter derived from animal manure, biofertilizers also include plant residues, products from the activity of microorganisms related to nitrogen fixation or the availability of phosphorus and other nutrients in the soil. 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 of the growth and yield traits in the two lentil cultivars. This treatment increased the traits of plant height, stem diameter, chlorophyll a, b and total, carotenoids, pods per plant, seeds per plant, grain yield and grain protein, and there was no significance for the protein yield trait. 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 integration of bio-fertilizers and chemical fertilizers was more effective than the separate application of each of them. Because the excessive use of chemical fertilizers alone has led to the collapse of sustainable and even organic agricultural systems in most regions of the world in recent decades. The complex policies of governments to produce high crop yields and increase incomes are among the most important reasons for the excessive use of chemical fertilizers and the subsequent destruction of soil and environment. The use of plants such as lentils, which are both a cover crop and a nitrogen-fixing plant that helps sequester carbon, can greatly reduce the destructive effects of excessive use of fertilizers and the problems of cultivation in damaged soils in agricultural lands. In the meantime, using the right and quality variety and determining the right planting date are necessary and essential to achieve high yields in crops, because the absence of these can incur high costs for farmers and severely 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 providing seeds of the requested lentil varieties.
کلیدواژهها English
