عنوان مقاله [English]
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.