تاثیر مصرف فسفریک اسید بر غلظت کلروفیل، نیتروژن، فسفر و پتاسیم و صفات زراعی گیاه ذرت در دو خاک مختلف

در این پژوهش، اثر مصرف فسفریک اسید صنعتی (h3po4) با خلوص 40 درصد بر رشد گیاه ذرت (zea mays l.) رقم سینگل کراس 704  در دو خاک با بافت لوم رسی و لوم شنی طی یک دوره رشد 45 روزه بررسی شد. آزمایش در گلخانه و در قالب طرح کاملاً تصادفی با 4 تیمار و 3 تکرار انجام شد. تیمارها شامل شاهد و فسفریک اسید در سه سطح 0.25، 0.5 و 1.0 گرم بر کیلوگرم خاک بودند. نتایج نشان داد که در هر دو خاک، اثر فسفریک اسید بر درصد جوانه‌زنی و تعداد برگ معنادار نبود. در خاک لوم رسی، مصرف فسفریک اسید با دوز 0.025 و 0.05 درصد باعث افزایش سرعت رشد، ارتفاع بوته، وزن تر بخش هوایی و ریشه، وزن خشک بخش هوایی و ریشه شد که در مقایسه با تیمار شاهد مقدار افزایش به‌ترتیب برابر با 30.7، 28.8، 69.3، 30.7، 55.4 و 30.7 درصد بود. همچنین، مصرف فسفریک اسید سبب افزایش غلظت کلروفیل برگ‌ها، مواد جامد محلول، ظرفیت آنتی‌اکسیدانی، غلظت فسفر، نیتروژن و پتاسیم بخش هوایی و ریشه شد اما بر غلظت کارتنوئید برگ‌ها اثر معنادار نداشت. در خاک لوم شنی، اثر فسفریک اسید بر وزن خشک بخش هوایی و ریشه و وزن تر بخش هوایی معنادار نبود اما بر وزن تر ریشه، غلظت کلروفیل برگ‌ها، مواد جامد محلول، ظرفیت آنتی‌اکسیدانی و غلظت فسفر، نیتروژن و پتاسیم بخش هوایی و ریشه، معنادار بود. نتایج نشان داد که  اثر فسفریک اسید بر ph و قابلیت هدایت الکتریکی (ec) خاک معنادار بود. در هر دو خاک لوم رسی و لوم شنی، تیمار  0.1 درصد فسفریک اسید، ph دو خاک را به‌ترتیب 2.7 و 1.5 درصد کاهش داد. در مقابل، ec دو خاک را به‌ترتیب 12.1 و 21.0 درصد افزایش داد. در خاک لوم رسی، اثر فسفریک اسید بر گیاه ذرت در مقایسه با خاک لوم شنی بیشتر بود. در شرایطی که خاک دارای مقادیر بالای آهک و ph است، توصیه می‌شود از فسفریک اسید به‌عنوان منبع تامین فسفر و برای اصلاح ph خاک استفاده شود.

effects of phosphoric acid application on concentrations of chlorophyll, nitrogen, phosphorus, and potassium, and agronomic traits of corn plants in two different soils

background and objectivescalcareous soils, typically found in arid and semi-arid regions of the world, cover approximately one-third of the earth’s surface. the high lime content and elevated ph level of these soils often limit the availability of nutrients such as phosphorus to plants. to address this issue, farmers commonly use various acids, such as phosphoric acid to supply the necessary phosphorus for plant growth and to improve soil conditions, which can also enhance the availability of other nutrients. therefore, this study aimed to evaluate the effects of different concentrations of phosphoric acid on leaf chlorophyll concentration, antioxidant capacity, and agronomic traits of corn (zea mays l.) plants in two different soils. materials and methodsto conduct the experiment, two soils with different textures (clay loam and sandy loam) were collected from a depth of 0–25 cm in tehran and alborz provinces. after air-drying, the soil samples were passed through a 2-mm sieve. the experiment was carried out in a greenhouse using a completely randomized design with four treatments and three replications. four levels of phosphoric acid (0.0, 0.25, 0.5, and 1.0 g per kg of soil) were applied as experimental treatments. industrial-grade phosphoric acid with a purity of 40% (h₃po₄) was used in this study. following the addition of phosphoric acid, the soils in the pots were homogenized through eight wetting-drying cycles. subsequently, 10 maize seeds (zea mays l.) cv. single cross 704 were sown in each pot. after germination and at the two-leaf stage, four vigorous seedlings were retained in each pot, and the others were removed. throughout the growth period, parameters such as germination rate, plant height, and growth rate were measured. at the end of the 45-day experimental period, fresh and dry weights of shoots and roots, plant height, leaf chlorophyll concentration, carotenoids concentration, antioxidant activity, soluble solids, leaf number, and also concentrations of nitrogen, phosphorus and potassium in shoot and root of plants were measured. resultsthe results demonstrated that phosphoric acid application had no significant effect on leaf number and germination percentage in both studied soils. moreover, in sandy loam soil, phosphoric acid application had no significant impact on plant height and overall growth rate. conversely, in clay loam soil, phosphoric acid application led to an increase in plant height, with the maximum enhancement (27.8%) recorded at the level of 0.5 g/kg. although different concentrations of phosphoric acid improved growth rate in clay loam soil, their effect on growth rate in sandy loam soil was not statistically significant. the phosphoric acid application resulted in increases in fresh and dry weights of shoot and root in both soils. in clay loam soil, the greatest increases in shoot fresh weight (69.3%) and root fresh weight (30.7%) were recorded at the phosphoric acid levels of 0.25 and 0.5 g/kg, respectively. in clay loam soil, the maximum increase in root dry weight (30.7%) and shoot dry weight (55.4%) were obtained at the phosphoric acid levels of 0.5 and 0.25 g/kg, respectively. in sandy loam soil, phosphoric acid had no significant effect on shoot and root dry weights and shoot fresh weight. however, it significantly enhanced nitrogen, phosphorus, and potassium concentrations in both shoot and root of plants in both studied soils. similarly, significant increases were observed in chlorophyll a, b, and total chlorophyll concentrations in both studied soils. the effect of phosphoric acid on carotenoids concentration in clay loam soil was not statistically significant. whereas in sandy loam soil, carotenoid levels declined with increasing the level of phosphoric acid, with the greatest reduction (66.2%) observed at the level of 1.0 g/kg. the application of phosphoric acid also significantly increased soluble solids content in both studied soils, with the highest increase recorded at 61.4% in clay loam soil and 46.1% in sandy loam soil. the highest antioxidant activity was observed at the levels of 1.0 and 0.25 g/kg in clay loam soil and sandy loam soil, respectively. furthermore, phosphoric acid significantly affected soil ph and electrical conductivity. in clay loam soil, the application of phosphoric acid at the levels of 0.25, 0.5, and 1.0 g/kg reduced soil ph by 0.33%, 1.54%, and 2.73%, respectively, compared to the control, while the corresponding reductions in sandy loam soil were 0.66%, 0.92%, and 1.49%. electrical conductivity increased in both soils, with the highest increases 12.1% in clay loam soil and 21.0% in sandy loam soil recorded under the phosphoric acid level of 1.0 g/kg. conclusionthe results of this study demonstrate that phosphoric acid application enhanced maize growth in both studied soils, with a more substantial effect observed in clay loam soil. as this experiment focused on a short-term assessment of phosphoric acid’s influence, it is recommended that future studies be conducted over longer durations and under field conditions to more accurately evaluate its long-term effects. moreover, assessing soil properties potentially affected by phosphoric acid application at both pre- and post-planting would contribute to a more comprehensive understanding of its overall impact.author contributionsconceptualization, a.h and m.b.s; methodology, m.s; performing expriments and measurements, m.t; software, a.h; validation, e.kh.; formal analysis, m.b.s and a.h.; data curation, m.s. and m.t.; writing—original draft preparation, e.kh and a.h.; writing–review and editing, m.b.s and a.h.; visualization, m.b.s.; supervision, a.h.; project administration, a.h.; funding acquisition, all authors have read and agreed to the published version of the manuscript.data availability statementdata is available on reasonable request from the authors.acknowledgementsthis paper is published as a part of a phd’s thesis supported by the vice chancellor for research and technology of the university of zanjan, zanjan, iran. the authors are thankful to the university of zanjan for financial supports.conflict of interestthe authors declare no conflict of interest.ethical considerations the authors avoided data fabrication, falsification, plagiarism, and misconduct.