بررسی اثر کیفیت بقایای گیاهی بر روند معدنی شدن نیتروژن در خاک در شرایط رطوبتی متفاوت

نوع مقاله : علمی - پژوهشی

نویسندگان

• الهه برومند رضازاده ¹
• علیرضا کوچکی ¹
• پرویز رضوانی مقدم ¹
• مهدی نصیری محلاتی ¹
• امیر لکزیان ²

¹ گروه زراعت و اصلاح و نباتات، دانشـکده کشـاورزی دانشگاه فردوسی مشهد، ایران.

² گروه علوم خاک ، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران

10.22067/jag.v9i3.51332

چکیده

به‌منظور بررسی روند تغییرات نیتروژن معدنی در خاک و چگونگی تأثیرپذیری آن از میزان رطوبت خاک و کیفیت بقایای گیاهی اضافه شده، تحقیقی در دانشکده کشاورزی دانشگاه فردوسی مشهد در قالب طرح اسپلیت پلات در زمان بر پایه طرح کاملاً تصادفی با سه تکرار به اجراء درآمد. بقایای گیاهی شامل گندم (Triticum aestivum L.)، کلزا (Brassica napus L.)، ذرت (Zea mays L.)، سویا (Glycin max L.) و پنبه (Gossypium hirsutum L.) بود و از خاک بدون بقایا نیز به عنوان شاهد استفاده شد. رطوبت خاک شامل سه سطح30، 60 و 100 درصد ظرفیت زراعی بود. در این مطالعه از روش کیسه لاشبرگ استفاده شد و نمونه‌برداری در طی زمان با فواصل 10، 20، 50، 90، 140، 190، 240، 290، 340 و 390 روز پس از شروع آزمایش صورت گرفت. نتایج نشان داد که کیفیت بقایا تأثیر به‌سزایی بر میزان نیتروژن معدنی خاک داشت و افزودن بقایای گیاهی سبب غیرمتحرک شدن آن شد. همچنین نیتروژن معدنی در خاک دارای بقایای گیاهی در ابتدای آزمایش (50-10 روز اول بسته به نوع بقایا) کاهش و سپس افزایش یافت. میزان غیرمتحرک شدن نیتروژن در خاک دارای بقایای گندم و پنبه (با نسبت کربن به نیتروژن بالاتر) بیش از بقایای سایر گیاهان بود. در هیچ یک از خاک‌های دارای بقایای گیاهی، معدنی شدن خالص نیتروژن مشاهده نگردید و بالاترین میزان نیتروژن معدنی مربوط به خاک شاهد بدون بقایا بود. رطوبت خاک نیز به عنوان یکی از عوامل مهم تعیین‌کننده میزان تجزیه بقایا و فعالیت زیست‌توده میکروبی، معدنی شدن نیتروژن را تحت تأثیر قرار داد، به نحوی‌که با افزایش رطوبت خاک میزان نیتروژن معدنی نیز افزایش نشان داد.

کلیدواژه‌ها

• ظرفیت زراعی
• غیرمتحرک شدن
• کیسه لاشبرگ
• نسبت C:N

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عنوان مقاله [English]

Net Nitrogen Mineralization as Affected by Residue Quality and Soil Moisture

نویسندگان [English]

• Elaheh Boroumand Rezazadeh ¹
• Alireza Koocheki ¹
• Parviz Rezvani Moghaddam ¹
• Mahdi Nasiri Mahalati ¹
• Amir Lakzian ²

¹ Department of Agronomy and Plant Breeding, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran

² Department of Soil Sciences, Faculty of Agriculture, Ferdowsi Uinversity of Mashhad, Mashhad, Iran

چکیده [English]

Introduction
Soil organic matter is one of the main sources of carbon, nitrogen, phosphorus and sulfur and the agronomic value of organic materials depends on their nitrogen release. Nitrogen dynamics varies considerably depending on soil properties (e.g. soil texture and moisture content), residue location (incorporation or surface placement residues) and intrinsic characteristics of residues, especially carbon to nitrogen ratio. The presence of carbonaceous compounds easily accessible by microorganisms increases organic nitrogen mineralization whereas more recalcitrant organic residues with large amounts of lignin reduce nitrogen release. Nitrogen content of residue which is rich in N releases and accumulates in soil during decomposition. Considerable portion of nitrogen content of non-leguminous residues harvested at green stage, with C/N ratio lower than 25, might be also released when the residues are incorporated into the soil.
Material and Methods
In order to study the nitrogen mineralization patterns of residues with different qualities and soil moisture contents, an experiment was conducted at Faculty of Agriculture, Ferdowsi university of Mashhad as slit-plot in time arrangement based on a completely randomized design with three replications. Five mature plant residues including wheat (Triticum aestivum L.), oilseed rape (Brassica napus L.), maize (Zea mays L.), soybean (Glycine max L.) and cotton (Gossypium hirsutum L.) were used. Un-amended soil was considered as control. Soil moisture consisted of three levels of 30, 60 and 100 percentage of field capacity. Litterbag method was used and sampling was conducted in 10, 20, 50, 90, 140, 190, 240, 290, 340 and 390 days after incubation (25°C and darkness) to measure mineral nitrogen. Net cumulative N mineralized was calculated as the difference between mineral nitrogen in each sampling and at day 0 and net N mineralization rate was defined as mineralized nitrogen divided by incubation period. Data analysis was performed using Minitab 16. Means were compared by Duncansʼ test at a significance level of 0.05.
Results and Discussion
Results indicated that soil mineral nitrogen was almost the same in all three levels of soil moisture in early day of the experiment and increased during incubation period. Mineral nitrogen was significantly affected by residue quality and soil moisture content. Soil moisture as a key factor in residue decomposition and microbial biomass activity affected nitrogen mineralization as the highest (59.9 mg.kg-1) and lowest (26.9 mg.kg-1) mineral nitrogen was found in soil moisture content of 100 and 30% FC, respectively. Net cumulative N mineralized was increased in un-amended control soil during the incubation period and reached to 61 mg.kg-1 in day 390 but a different trend was observed in amended soils. In these treatments mineral nitrogen changes had two distinct phases: the first phase included mineral nitrogen immobilization and the intensity and duration of this phase was related to residue type and especially their initial nitrogen content. The second phase lasted to the end of the incubation period, included nitrogen mineralization. Soil amendment with plant residue led to soil nitrogen immobilization. The highest immobilization was observed in soils containing wheat (-7 mg.kg-1) and cotton (-5.2 mg.kg-1) residues (containing high carbon to nitrogen ratio). No net N mineralization was found in amended soils. The highest net N mineralization rate was found in control followed by soils amended with soybean residues (0.14 mg.kg-1.d-1) and the lowest in soils amended with wheat and cotton.
Conclusion
Results of the present study indicated that the net N mineralization rate and soil mineral nitrogen was significantly affected by residue quality and residues with higher nitrogen content led to nitrogen immobilization. Soil moisture also played an important role in nitrogen mineralization as higher mineral nitrogen was found in soils with higher moisture content.

کلیدواژه‌ها [English]

• C:N Ratio
• Field capacity
• Immobilization
• Litterbag
• Net Cumulative-N Mineralized

مراجع

Abiven, S., Recous, S., Reyes, V., and Oliver, V. 2005. Mineralisation of C and N from root, stem and leaf residues in soil and role of their biochemical quality. Biology and Fertility of Soils 42: 119–128.

Ajwa, H.A., and Tabatabai, M.A. 1994. Decomposition of different organic materials in soils. Biology and Fertility of Soils 18: 175–182.

Amador, J.A., Görres, J.H., and Savin, M.C. 2005. Role of soil water content in the carbon and N dynamics of Lumbricus terrestris L. burrow soil. Applied Soil Ecology 28: 15–22.

Ambus, P., and Jensen, E.S. 2001. Crop residue management strategies to reduce N losses-interaction with crop N supply. Communications in Soil Science and Plant Analysis 32: 981–996.

Azam, F., Simmons, F.W., and Mulvaney, R.L. 1993. Mineralization of N from plant residues and its interaction with native soil N. Soil Biology and Biochemistry 25: 1787-1792.

Azam, F., Sajjad, M.H., Lodhi, A., and Qureshi, R.M. 2005. Changes in forms of N During decomposition of leguminous/non-leguminous plant residues in soil and fate of 15N-labelled fertilizer applied to wheat (Triticum aestivum L.). Asian Journal of Plant Sciences 4: 392-400.

De Neve, Hartmann, R., and Hofman, G. 2003. Temperature effects on N mineralizing: changes in soil solution composition and determination of temperature coefficients by TDR. European Journal of Soil Science 54: 49–61.

Fosu, M., Kühne, R.F., and Vlek, P.L.G. 2007. Mineralization and microbial biomass dynamics during decomposition of four leguminous residues. Journal of Biological Sciences 7: 632-637.

Franzlubbers, K., R.W. Weaver, Juo, A.S.R., and A.J. Franzluebbers. 1994. Carbon and nitrogen mineralization from cowpea plants part decomposing in moist and in repeatedly dried and wetted soil. Soil Biology and Biochemistry 26: 1379–1387.

Green, C.J., and Blackmer, A.M. 1995. Residue decomposition effects on nitrogen availability to corn following corn or soybean. Soil Science Society of America Journal 59: 1065–1070.

Hemwong, S., Cadisch, G., Toomsan, B., Limpinuntana, V., Vityakon, P., and Patanothai, A. 2008. Dynamics of residue decomposition and N2 fixation of grain legumes upon sugarcane residue retention as an alternative to burning. Soil and Tillage Research 99: 84–97.

Henriksen, T.M., and Breland, T.A. 1999. Evaluation of criteria for describing crop residue degradability in a model of carbon and nitrogen turnover in soil. Soil Biology and Biochemistry 31: 1135-1149.

Ibewiro, B., Sanginga, N., Vanlauwe, B., and Merckx, R. 2000. Nitrogen contributions from decomposing cover crop residues to maize in a tropical derived savanna. Nutrient Cycling in Agroecosystems 57: 131-140.

Kara, E.E. 2000. Effects of some plant residues on nitrogen mineralization and biological activity in soils. Turkish Journal of Agriculture and Forestry 24: 457-460.

Knoepp, J.D., and Swank, W.T. 2002. Using soil temperature and moisture to predict forest soil nitrogen mineralization. Biology and Fertility of Soils 36: 177–182.

Mary, B., Recous, S., Darwis D., and Robin, D. 1996. Interactions between decomposition of plant residues and nitrogen cycling in soil. Plant and soil 181: 71-82.

Mendham, D.S., Kumaraswamy, S., Balasundaran, M., Sankaran, K.V., Corbeels, M., Grove, T.S., O’Connell A.M., and Rance, S.J. 2004. Legume cover cropping effects on early growth and soil nitrogen supply in eucalypt plantations in south-western India. Biology and Fertility of Soils 39: 375–382.

Nicolardot, B., Fauvet, G., and Cheneby, D. 1994. Carbon and nitrogen cycling through soil microbial biomass at various temperatures. Soil Biology and Biochemistry 26: 253–261.

Nicolardot, B., Recous, S., and Mary, B. 2001. Simulation of C and N mineralization during crop residue decomposition: a simple dynamics model based on the C:N ratio of the residue. Plant and Soil 228: 83–103.

Nicolardot, B., Bouziri, L., Bastian, F., and Ranjard, L. 2007. A microcosm experiment to evaluate the influence f location and quality of plant residues on residue decomposition and genetic structure of soil microbial communities. Soil Biology and Biochemistry 39: 1631-1644.

Palm, C.A., Gachengo, C., Delve, R., Cadisch, G., and Giller, K.E. 2001. Organic inputs for soil fertility management in tropical agroecosystems: application of an organic resource database. Agriculture, Ecosystems and Environment 83: 27–42.

Raiesi, F. 2006. Carbon and N mineralization as affected by soil cultivation and crop residue in a calcareous wetland ecosystem in Central Iran. Agriculture, Ecosystems and Environment 112: 13–20.

Sakala, W.D., Cadisch, G., and Giller, K.E. 2000. Interactions between residues of maize and pigeonpea and mineral N fertilizers during decomposition and N mineralization. Soil Biology and Biochemistry 32: 679-688.

Sierra, J. 1997. Temperature and soil moisture dependent of N mineralization in intact soil cores. Soil Biology and Biochemistry 29: 1557–1563.

Soon, Y.K., and Abboud, S. 2002. Comparision of the decomposition and N and P mineralization of canola, pea and wheat residues. Biology and Fertility of Soils 36: 1017-1026.

Stark, J.M., and Firestone, M.K. 1996. Kinetic characteristics of ammoniumoxidizer communities in a California oak woodland-annual grassland. Soil Biology and Biochemistry 28: 1307–1317.

Wang, C., Wan, S., Xing, X., Zhang, L., and Han, X. 2006. Temperature and soil moisture interactively affected soil net N mineralization in temperate grassland in Northern China. Soil Biology and Biochemistry 38: 1101–1110.

Zaccheo, P., Cabassia, G., Riccab, G., and Crippaa, L. 2002. Decomposition of organic residues in soil: experimental technique and spectroscopic approach. Organic Geochemistry 33: 327–345.