Soil science
H. Auobi; J. Nabati; Ahmad Nezami; M. Kafi
Abstract
Introduction: The excessive use of chemical fertilizers devastates soil fertility and causes different types of environmental pollution. Therefore, using adequate eco-friendly fertilizers in agriculture enhances productivity but has no adverse effect on nature. Recently, there has been reported that ...
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Introduction: The excessive use of chemical fertilizers devastates soil fertility and causes different types of environmental pollution. Therefore, using adequate eco-friendly fertilizers in agriculture enhances productivity but has no adverse effect on nature. Recently, there has been reported that beneficial soil microbes produce some volatile organic compounds, which are beneficial to plants. The amendment of these microbes with locally available organic materials and nanoparticles is currently used to formulate biofertilizers for increasing plant productivity. These bacteria are naturally present in soils, but their population decreases for a long time because of long-term environmental stress, improper use of chemical agents, and the absence of a suitable host plant. Adding these bacteria to the soil, before or during the growing season, increases the growth and production of agricultural products. Since available water is the main growth limiting factor in chickpea cultivation, it is useful to improve nutrition, especially using plant growth-promoting rhizobacteria, for accelerating the growth and development of plants at the end of the season.
Materials and Methods: In order to evaluate the effect of bio-nutrition and seed priming on growth and yield of chickpea genotypes (MCC463, MCC741, ILC8617, ILC72, FLIP02-51C) an experiment was carried in split plots based on Randomized Complete Block Design with three replications in 2019. Experimental factors included nutritional treatments as the main plots and chickpea genotypes as the subplots. Nutritional treatments were 1- seed priming with the use of free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria (P + BF), 2- free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria before sowing (BF), 3- seed priming with the application of free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria with foliar application of amino acid, potassium and silicon during growth stages (P + BF + F), 4- application of free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria before planting with foliar application of amino acid, potassium and silicon during growth stages (BF + F), and 5- control (without biological and chemical fertilizers). Free-living nitrogen fixing bacteria, phosphorus solubilizing bacteria and potassium solubilizing bacteria were sprayed five liters per hectare on the soil surface before planting with 107 CFU per ml and mixed with soil. Foliar application with amino acid (1:1000) was done in two stages (before flowering and 50% flowering stage), and foliar application with potassium (1:1000) and silicon (1.5:1000) was carried out in the 50% flowering stage.
Results and Discussion: Results showed that the highest concentration of chlorophyll a was obtained for BF and MCC463 with an increase of 3.1 times greater than control. The highest concentration of chlorophyll b was obtained for BF + F and FLIP02-51. The highest green area index was recorded for MCC741 in P + BF. The highest number of pods per plant in MCC463 and FLIP02-51 was observed in BF + F, with 88 and 30% more than the control, respectively. The highest biomass produced was obtained for ILC8617 and BF + F, by 24% higher than the control. ILC72 and MCC463 showed the highest grain yield in P + BF + F treatment, which increased grain yield by 35% and 4% (320 and 50 kg/ha), respectively, with respect to control. MCC741under BF treatment showed a doubled (810 kg/ha) grain yield relative to control. The highest grain yield for P + BF was found in ILC8617 and increased by 28% (340 kg/ha) as compared to control. In this genotype, grain yield in BF + F was also significantly greater than that in the control by 22%, (270 kg/ha). FLIP02-51 grain yield in BF increased by 12% (170 kg/ha) as compared with the control.
Conclusion: In terms of seed yield, ILC72 and MCC463 were more responsive to P + BF + F and ILC8617 and FLIP02-51 in the BF and ILC8617 in P + BF with respect to other treatments. It seems that despite the positive effect of biofertilizer, genetic characteristics of genotypes are influential in plant growth and yield; therefore, it is necessary to select the appropriate genotype for each region so as to make the most utilization of the nutrients and achieve high yield.
atena mirbolook; Mirhasan Rasouli-Sadaghiani; E. Sepehr; A. Lakzian; M. Hakimi
Abstract
Introduction: Iron (Fe) is an important micronutrient that plays a role in several crop physiological processes such as photosynthesis, respiration, and synthesis of heme proteins, DNA, RNA, and hormones. The most common Fe source used in agriculture is Fe-EDDHA. However, the usage of this chelate may ...
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Introduction: Iron (Fe) is an important micronutrient that plays a role in several crop physiological processes such as photosynthesis, respiration, and synthesis of heme proteins, DNA, RNA, and hormones. The most common Fe source used in agriculture is Fe-EDDHA. However, the usage of this chelate may be problematic for plant growth. In the recent years, organic chelates have gained attention as they increase the microelements solubility and prevent iron precipitation in nutrient solution. Organic chelates such as amino acids and polysaccharides have many physicochemical (reactive OH, COOH and NH2 groups) and biological (biocompatible and biodegradable) properties that make these attractive materials usable for the agricultural practice. Biodegradability, low toxicity, immune system stimulation, the ability to coordinate metal, less sensitivity to photodegradation, and the effect on physical properties of rhizosphere and root growth dynamic are ideal properties of these components. The objective of this study was to evaluate Fe-organic-chelates efficiency as Fe sources for bean (Strategy I) and corn (Strategy II) growth in the hydroponic system. Materials and Methods: In this research, we synthesized Fe-amino acid chelates including Fe-Glycine (Fe-Gly), Fe-Phenylalanine (Fe-Phe), Fe-Tyrosine (Fe-Tyr), Fe-Methionine (Fe-Met), and Fe chitosan chelates in two forms of acidic hydrolyzed chitosan [Fe-C(A.hyd)] and enzymatic hydrolyzed chitosan [Fe-C(E.hyd)] and characterized by FTIR and CHN analyzer. The efficiency of these iron sources for bean (Strategy II) and corn (Strategy I) in hydroponic system was then evaluated. Seeds of bean and corn were washed with distilled water and transplanted into special containers containing coco peat, perlite and vermicompost (1:1:1) at 25 °C for germination and initial growth. The seedlings were transferred to polyethylene plastic lids fitting tightly over 8-L polyethylene containers under controlled conditions in the greenhouse with a light period of 8 hours per day, the temperature of 20 to 25°C and relative humidity of 65 to 75%. The pots were stacked in black color to prevent light reaching the root of the plant and the solution. In each pot, one plant seedling was placed and the basic nutrient solution was prepared in deionized water. The plants were harvested after 8 weeks, their root and shoot were separated and dried after washing with distilled water in an oven at 75 ° C. The dried samples were ground to fine powder to pass through a 20-mesh sieve. The analysis of Fe in samples was performed using atomic absorption spectrophotometer. Result and Discussion: Application of organic chelates of amino acids and chitosan increased the shoot dry matter per plant compared to Fe-EDDHA. Fe content in shoot of corn and bean was highest using Fe-Tyr, Fe-Met and [Fe-C(A.hyd)]. Uptake and accumulation of Fe in roots were observed by using all chelates, but the highest translocation factor was found for the treatments including [Fe-C(A.hyd)] and Fe-Tyr. Translocation factor in bean plants was higher than corn, and around half of Fe in bean plants was translocated from root to shoot. The use of iron chelates in plant growth medium increased the activity of ferric chelates reductase enzymes in bean and corn compared to Fe-EDDHA. However, the mean of this enzyme activity in bean was higher than that in corn. Therefore, the activity of this enzyme can be used as an indicator for determining the iron availability in leaf cells in Strategy I and Strategy II plants. In general, the plants need less energy to absorb Fe when the chelates with a simpler structure are used. Conclusion: The results indicated that using Fe organic chelates in the hydroponic system could supply sufficient amounts of iron for the plant uptake and also improve the root and the shoot growth of bean and corn. Overall, the effect of Fe organic chelates on Fe content of bean and corn shoots was in the following order: Fe- Chi(A.hyd) > Fe-Tyr > Fe-Met > Fe-Gly >. Activity of leaf ferric chelate reductase in bean was higher than that in corn.
