Plant Nutrition, Soil Fertility and Fertilizers
samira mohamadi; Fardin Sadegh-Zadeh; Mohammad AIi bahmanyar; mostafa emadi; mahdi ghajar- sepanlu
Abstract
Introduction: Recovery of nutrients from plant residues is a sustainable and economical method in agriculture. Considering the important role of nutrients, it is essential to supply these elements in the soil and achieve the appropriate yield. The amount of nutrients in the plant residues after harvesting ...
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Introduction: Recovery of nutrients from plant residues is a sustainable and economical method in agriculture. Considering the important role of nutrients, it is essential to supply these elements in the soil and achieve the appropriate yield. The amount of nutrients in the plant residues after harvesting is very variable due to the difference between the species used. Each plant residue contains some nutrients that during the decomposition process, these nutrients can be available to the soil and crops in different amounts. In more detail, considering that the excessive use of chemical fertilizers has caused environmental problems and unused plant residues in the environment have created problems for the environment and farmers, therefore, to solve these problems, recovering important elements such as silicon from plant residues can be effective in improving the quality and quantity of many different products and plants. Rice straw, wheat straw and sugarcane bagasse are among the most common plant residues that have been studied in different studies to recover nutrients from them with different methods. In particular, rice straw is known as one of the most important plant residues that can be found in abundance in the north of Iran. Obviously, there is still a need for a better understanding of the amount of nutrients recovery from plant residues with different methods. And there is an effect of these elements on improving the condition of the soil. Considering that the excessive use of chemical fertilizers has caused environmental problems, as well as unused or underused plant residues in the environment have caused problems for the environment and farmers. The purpose of this study is to compare the residues of rice straw, wheat straw and sugarcane bagasse and the methods of recovering nutrients from these residues in order to add macro-nutrients (nitrogen, phosphorus and potassium) and micro-nutrients (iron, zinc, copper and manganese) into the soil.Materials and Methods: This research was carried out based on a factorial experiment in the form of a completely "randomized" design with three replications during 2022-2023. The treatments of plant residues in three levels (rice straw, wheat straw and sugarcane bagasse) and the methods of recovering elements from these residues in five levels (biochar, straw, digestion, ash and ash with acid) were examined. Soil samples, from a depth of 0-25 cm and with silty loam texture were randomly taken from the forest parts of Mazandaran province, Iran, characterized by a Mediterranean climate, Csa type, with an average annual rainfall of 676 mm, and average air temperature of 14 ℃, and then were air-dried. After preparing the samples, the characteristics of the treatments, macronutrients and micronutrients, including pH, electrical conductivity, total nitrogen, phosphorus, potassium, iron, zinc, manganese, copper, and silicon were measured. Analysis of variance (ANOVA) assessed the statistical significance of the differences in the studied variables among the different treatments. Tukey test was used for the post-hoc comparisons at a p-level < 0.01. Prior to the statistical analysis, QQ-plots were used to check the normality of sample distribution, and the data were square root-transformed whenever necessary. Moreover, the principal component analysis (PCA) was used to cluster the studied variables in groups related to the studied treatments.Results and Discussion: The results of analysis of variance showed the effect of plant residues and element recovery method on all studied characteristics including soil characteristics (pH, electrical conductivity and organic carbon), macronutrients (nitrogen, phosphorus and potassium) and micronutrients (silicon, manganese, copper, iron and zinc) were significant at the probability level of 1%. The results showed that the biochar treatment of rice straw had the maximum amount of pH (7.66), organic carbon (2.61%), nitrogen (0.24%), phosphorus (46 mg/g), potassium (781 mg/g) and silicon (261.33 mg/g) compared to other treatments. Also, the results of the compare means showed that sugarcane bagasse biochar treatment had the maximum amount of manganese (25.01 mg/kg), zinc (3.20 mg/kg), iron (48.27 mg/kg) and copper (2.20 mg/kg) compared to other treatments. The application of principal component analysis showed that three distinct groups (for rice straw/biochar, sugarcane bagasse/biochar and control treatments) were demonstrated, without clear overlap of the points related to these treatments and their element recovery methods.Conclusions: In general, this study confirmed that the treatment of rice straw residues and the method of recovering its elements through biochar play a significant role in increasing the quality and fertility of the soil and can be recommended to farmers.
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.