نوع مقاله : مقاله پژوهشی
نویسندگان
1 مؤسسه تحقیقات خاک و آب، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران
2 - بخش تحقیقات شوری، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان بوشهر. سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The availability and efficient utilization of phosphorus, an essential nutrient in agricultural production, through fertigation systems requires precise determination of application rates and an understanding of phosphorus movement and distribution in the soil layers surrounding crops. This study aimed to evaluate the distribution of soluble phosphorus (SSP) and available phosphorus (SAP) in agricultural soil under maize cultivation and in bare soil during two fertigation cycles over various time periods at the Soil and Water Research Institute (Karaj). After tillage, maize was planted using a strip and single-row method, with row and plant spacings of 60 cm and 15 cm, respectively. Following fertigation in both cycles, using micro auger soil samples were collected from both bare soil and soil under maize at horizontal distances of 5 and 10 cm from the dripper and at depths of 0-5, 5-10, 10-15, 15-20, 20-30, and 30-40 cm at time intervals of 4, 24, 98, and 960 hours, with two plant replications (two sides of each plants). The samples were subsequently transferred to the laboratory for chemical analysis using conventional measurement methods. The results indicated that fertigation, depth, and time significantly affected the distribution of SSP and SAP in both systematic and non-systematic manners. The analysis of variance revealed that the effect of the fertigation cycle treatment on SSP and SAP under maize cultivation at 5 and 10 cm from the fertilizer injection site was significant (at the 1% statistical level), demonstrating a phosphorus movement of approximately 10 cm within this system. As the depth increased, the average SSP and SAP values exhibited a decreasing trend. The maximum average concentration across all treatments was observed 98 hours after fertilizer injection, indicating an optimal time range for easily accessible phosphorus availability. Overall, due to the unique properties of phosphorus in soil—such as low solubility, low mobility, and high stabilization/fixation by the soil matrix—along with its availability for plants, it is preferable to apply phosphorus fertilizers in a soluble form, approximately 5 centimeters away from the crop, and in more frequent applications.
کلیدواژه‌ها [English]
The agricultural sector faces numerous challenges concerning the utilization of water and mineral resources for crop production and food security. Classic methods of phosphorus fertilization have demonstrated limitations in phosphorus absorption and efficiency of use. The emergence of new technologies, particularly drip fertigation, has facilitated greater solubility and efficiency in phosphorus utilization. The amount of water and fertilizer used, as well as their timing in drip irrigation systems, are critical issues that require optimization. Recently, phosphorus drip fertilization has been proposed as an efficient agricultural practice to enhance phosphorus use efficiency by crops, as it delivers nutrients at the right time and place for plant uptake. This research examines the movement of phosphorus in the soil while gaining a proper understanding of the conditions of drip fertigation, including timing and soil depth, with the aim of achieving increased productivity per unit area to meet nutritional needs and optimize irrigation and fertilization techniques effectively.
The present study aimed to assess the distribution of soluble phosphorus (SSP) and available phosphorus (SAP) in agricultural soil under maize cultivation and in bare soil, during two fertigation cycles over different time periods, at the Soil and Water Research Institute (Karaj). Following land preparation, maize was planted in strip and single-row arrangements, with row and plant spacing sets at 60 cm and 15 cm, respectively. After injecting the fertigation solution during the both cycles, soil samples were collected from both bare soil and soil under maize at horizontal distances of 5 and 10 cm from the plant, and at various depths of 0-5, 5-10, 10-15, 15-20, 20-30, and 30-40 cm. Sampling was conducted at time intervals of 4, 24, 98, and 960 hours, with two plant replications (two plants each) for laboratory analysis. The samples were then transported to the laboratory for chemical analysis using conventional measurement methods.
The results of the simple effect of fertigation on the traits indicated that the average SSP and SAP during the second fertigation cycle were significantly higher than those in the first cycle. Conversely, the average SSP and SAP values in bare soil conditions were found to be higher compared to those under maize cultivation. Overall, from the 0 to 5 cm depth, the average values of SSP and SAP decreased as the depth increased. However, no significant differences were observed between the depths of 10, 20, and 30 cm (with vertical movement around 10 cm). The influence of time on phosphorus concentration shows that with the passage of time, an increasing trend began 4 hours after the fertigation injection, with the maximum average observed in all treatments at 98h after fertigation, after which it reached the minimum average at 960 hours. Based on the interaction effects of fertigation and depth (F*D), the highest SSP values in bare soil and under maize cultivation were recorded at L5 and L10, corresponding to F2D1, while the lowest values were associated with F1D6. Soluble and available phosphorus in bare soil was measured with a higher average compared to the soil under maize cultivation. Additionally, according to the results of the mean comparisons, phosphorus values decreased with increasing depth during both fertigation cycles, reaching a minimum at deeper layers. Given that the simple effect of time indicates that initially, after the fertigation injection, phosphorus concentrations gradually increased due to interactions and distribution in the soil during the early hours, and peaked at 98 hours, subsequent factors such as leaching, plant uptake, soil interactions, and transformation of phosphorus forms into non-available forms contributed to the observed reduction.
In this research, a general overview of the availability, movement of phosphorus in drip fertigation, and its distribution at various depths and times has been reported. We believe that the fundamental topics and practical recommendations regarding the management of phosphorus drip fertigation presented in this research paper, including the distribution of fertilization in more frequent intervals and considering the maximum movement of phosphorus up to a limit of 10 cm vertically, horizontally, and laterally, will be of interest to researchers in the agricultural field, farmers, and industries for improving the efficiency of water and phosphorus fertilizer application under drip fertigation regimes.
The study was conceptualized by Meisam Rezaei, Kambiz Bazargan and Karim Shahbazi who also provided oversight for project administration and funding acquisition. The methodology was developed by Meisam Rezaei, while the software utilized for data analysis was also implemented by Meisam Rezaei and Somayeh Dehghani. Validation of the findings involved all authors ensuring the robustness of the results. The formal analysis and investigation were conducted by Meisam Rezaei, who also managed the resources and data curation essential for the research. The original draft of the manuscript was prepared by Meisam Rezaei and Somayeh Dehghani, followed by comprehensive writing—review and editing conducted by all authors. Visualization of the data was performed by Somayeh Dehghani. All authors have read and agreed to the published version of the manuscript.
The data that support the findings of this study are available from the corresponding author upon reasonable request.
This work was part of the project titled "Assessing and Modeling the Distribution and Dynamics of Phosphorus and Potassium in Maize and Potato Cultivated Under Drip Irrigation," funded by the Iranian National Elites Foundation and the Soil and Water Research Institute of Iran (SWRI). The authors express their gratitude to all study participants for their contributions and to the SWRI laboratory staff for their invaluable technical support.
The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The authors declare no conflict of interest.
)