T. Nazari; M. Baranimotlgh; E. Dordipour; R. Ghorbani nasrabadi; S. Sefidgar Shahkolaee
Abstract
Introduction One of the most important needs in crop planning is the evaluation of different systems of plant nutrition. plant nutrition in a correct way can preserve the environment and increase efficiency of agricultural inputs. Humic acid contains many nutrients that increase the soil fertility and ...
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Introduction One of the most important needs in crop planning is the evaluation of different systems of plant nutrition. plant nutrition in a correct way can preserve the environment and increase efficiency of agricultural inputs. Humic acid contains many nutrients that increase the soil fertility and soil organic matter content and thus affect plant growth and yield. In the present study, the effect of soil and foliar application as well as fertigation application of humic acid on iron and phosphorous availability of canola (Hyola 308) was evaluated. Materials and Methods The soil was air-dried and ground to pass through a 2-mm sieve and then was analyzed to determine soil physical and chemical properties using standard methods. A greenhouse experiment was carried out with 10 treatments in four replications. Treatments include humic acid soil application at three levels (1, 2 and 4 g.kg-1 soil), foliar application at three levels (0.1, 0.2 and 0.4%) and three fertigation levels (1000, 2000 and 4000 mg L-1) and control). Soil application in the form of humic acid powder and in cropping time based on the soil weight of the pots and for spraying and use along with irrigation water, each of the spraying and together with irrigation water levels is divided into three equal parts and in three stages (plant establishment, stem elongation and flowering). At the end of growth period (for 139 days), vegetative growth indices were determined and then plants were harvested and stem and leaves were separated. Phosphorous content in plant extracts was measured by molybdate vanadate method (yellow method) and iron concentration in the samples was determined by atomic absorption (AAS-Unicam-919). Statistical analysis was conducted via SAS software and mean comparisons carried out by LSD test at 5% probability level. Results and Discussion Results show that the application methods and the different levels of humic acid had significant impacts (p < 0.01) on the all parameters but they had no significant effects on the numbers of leaves. The maximum leaf fresh weight was 4.34 gr per plant which obtained water irrigated treatments with 2000 mg/lit. However, there was no significant difference between water irrigation with 4000 and 2000 mg/lit humic acid concentrations. Besides, maximum leaf dry weight was 0.37 gr in the plant that was water irrigated with 4000 mg/lit, however there was no significant difference between water irrigation with 4000 and 2000 mg/lit humic acid concentrations. Also, the maximum stem dry and fresh weight was 5.92 and 1.53 gr which observed in water irrigated with 2000 mg/lit. The application methods and the different levels of humic acid had significant impact (p<0.01) on the content and absorption of Fe and P excluding the Fe content in the root. The maximum Fe content in stem and seed were 321.25 and 85 mg/kg was observed in the treatment of humic acid with water irrigation of 2000 mg/lit. Also, in the treatment of spraying with 0.4 % of humic acid, the maximum of Fe concentration (245.46 mg/kg) was obtained. The humic acid molecules can pass from the cell membranes and cause iron reduction in the Apoplast and increase the availability of Fe. Because of the reduction effect of humic acid on the availability and accumulation of Fe in the plant tissue, increasing in the Fe absorption with humic acid treatment is observed. The increase in the accumulation of Fe by humic material might be due to the releasing phenolic material in the root rhizosphere. The maximum P concentration in the leaf, stem and seed were 0.40, 0.72 and 0.897 respectively that was observed in the treatment of water irrigation with 2000 mg/lit with humic acid. Due to the availability of phosphorus and other nutrients for wheat, humic acid increases the plant yield in the reproductive stage of seeding. Conclusion Results of the study show that humic acid can ameliorate the negative effect of a large amount of phosphorus on iron availability. In fact, humic acid, due to providing nutritional balance for the plant, prevents negative effects caused by the high amounts of specific elements such as phosphorus. Also, the results showed that all three humic acid application methods increased vegetative growth parameters, and iron and phosphate availability for canola plant compared to control. But in general, 2000 mg/L acid humic with irrigation water was more effective than two methods of soil and foliar application.
Plant Nutrition, Soil Fertility and Fertilizers
Amir Rahimi; Behnam Doulati; Saied Heydarzadeh
Abstract
Introduction Nutritional deficiencies (e.g. Iron, Zinc, Manganese and Boron) account for almost two‐thirds of the childhood death worldwide. Most of those afflicted are dependent on staple crops for their sustenance. Declining soil fertility in many countries, duo to continuous cropping systems, has ...
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Introduction Nutritional deficiencies (e.g. Iron, Zinc, Manganese and Boron) account for almost two‐thirds of the childhood death worldwide. Most of those afflicted are dependent on staple crops for their sustenance. Declining soil fertility in many countries, duo to continuous cropping systems, has reduced soil production capacity affected by depletion of soil nutrient without proper replacement. Soil application of prepared humic substances is not economical, but the response to foliar sprays has the potential to be economical because the relatively small quantities are needed. Foliar application is one of the swift response methods for plants to add fertilizer, which leads to dispel of nutrients deficiency and providence in the use of chemical fertilizers. The solubility of nutrients decreases in soils with high acidity or undesirable chemical composition and can be possibility of ionic competition (Antagonism) or the accumulation of nutrient in soilcanlee resulthed. Therefore, adsorption of nutrients and root growth will be inappropriate. On the other hand, the application of humic substance with improving physical, chemical and biological conditions causes an increase in adsorption and soil fertility. Using humic substances is another benefit of the reduction of environmental pollution in order to achieve sustainable agriculture. A sugar beet is a plant whose root contains a high concentration of sucrose and which is grown commercially for sugar production. Sugar beet is one of the strategic crops and is widely cultivated in the West Azerbaijan region. So, the aim of this study was to investigate the application of humic substances and micronutrient on some quantitative and qualitative characteristics of sugar beet. Material and Methods This study was carried out as a randomized complete block design with six levels of humic substance (0, 200, 300, 400, 500, 600 kg ha-1) and foliar application of micronutrients including Fe, Zn, B, and Mn with 3 replications. Physicochemical properties of soil (calcium carbonate equilibrium, pH, OC, EC, micro and macro elements, soil texture) were determined by standard methods. There fore, quantitative and qualitative characteristics of sugar beet including total sugar content, pure sugar content, and molasses sugar content, Na, K and N content in root, alkalinity, sugar extraction coefficient, root yield and pure sugar and total sugar yield were determined in sugar beet samples. Results The results showed that the application of humic and micronutrient was significant in qualitative and quantitative characteristics of sugar beet. Maximum root yield (68.96 ton ha-1) was obtained in the Mn treatment. The highest of pure (16.30%), gross sugars (18.68%) and sugar extraction coefficient (87.25%) was observed in B and 500 kg ha-1 of humic asid treatment. Humic acid application increased nitrogen (27.58%) and root yield (29.08%) compared to control. Also, micronutrient and humic substance application reduced the molasses sugar content and increased potassium in the root of sugar beet. So that the highest (3.48%) and lowest (2.37%) amounts of molasses sugar were obtained in control and 500 kg ha-1 humic acid plus B treatment respectively. Boron is much required for cell division and development in the growth regions of the plant near the tips of shoots and roots. It also affects sugar transport and appears to be associated with some of the functions of calcium. Conclusion According to the results of this study, foliar application of humic substance and micronutrient improved qualitative and quantitative characteristics of sugar beet. The root and refined sugar yields are among the most important components in sugar beet production. Also, treatment of 600 kg ha-1 of humic acid and Mn spraying had the greatest effect on the root and gross sugars yield in sugar beet. Also, the amount of molasses sugar decreased with increasing sugar content and replacing potassium instead of harmful elements. Application of Mn and B may need to be considered for sugar beets. Foliar fertilization with Mn has the beneficial effect mainly on such features like White sugar yield, root, gross sugars yield, and the number of leaves per single sugar beet plants. It can be concluded that the contemporary use of humic substance and micronutrient is recommended in order to achieve adequate yield and preserve the environment.
