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Showing 3 results for Nitrification
Calibration of Nitrate Leaching and Water Table Fluctuation in Paddy Rice Field by DRAINMOD-N Software
H. Zare Abyaneh, H.noori, A.m.liaghat, V.karimi, H.noori,
Volume 15, Issue 57 (10-2011)
Abstract
Fertilizers in agriculture are potential sources of environmental pollution, especially in ground water quality and soil resources. Studying factors effective in water and nutrient transport through soil profile is helpful for nutrient management to minimize adverse impacts on environment and nitrate leaching below the root zone. In this study, the ground water level and nitrate leaching transportation below the root zone were measured in a paddy rice field and the data were simulated with the DRAINMOD-N model. For evaluating DRAINMOD-N software in a paddy rice field under surface drainage in Mazandaran, the ground water level and nitrate transportation were measured during four months (June, July, August and September) in 2008. The DRAINMOD-N model was calibrated by adjusting nitrification and denitrification rate constants to reach the best fit between measured and predicted data. Results indicate that predicted ground water level and nitrate concentration by model were significant at one percent level. The statistical comparison was done by model efficiency (EF) 0.84 for estimation of ground water level and 0.97 for estimation of nitrate concentration, respectively. The DRAINMOD-N model can be used as a tool to manage environmental pollution of nitrate in paddy rice fields.
Effects of Moisture Conditions and Ammonium Concentration on Nitrification in Two Soils with Different Textures
R. Darabi Kandlaji, Shahin Oustan, Nasser Aliasgharzad, N. Najafi,
Volume 22, Issue 3 (11-2018)
Abstract
Nitrification is one of the most active biological processes in the soils receiving ammonium nitrogen. The rate of this process is under the influence of several factors and their interactions. In this study, the effects of ammonium concentration and moisture content on the extent of nitrification in two soil samples named A (Loam) and B (Clay loam), which had been taken, respectively, from Marand and Ahar areas, were investigated. A two-week factorial incubation experiment (25±0.5°C) was conducted in a completely randomized design with three replications. Factors were urea nitrogen at five levels (0, 50, 100, 200 and 400 mg N kg-1), moisture content at three levels (0.55FC-0.60FC, 0.75FC-0.80FC and 0.95FC-FC) and two soil types (A and B). At the end of the experiment, concentrations of ammonium and nitrate as well as the values of pH and EC were determined. Based on the results, average nitrification at 0.55FC-0.60FC was 22 percent lower than that at 0.95FC-FC and no significant difference was observed between 0.75FC-0.80FC and 0.95FC-FC. Nitrification at the treatment of 400 mg N kg-1and 0.55FC-0.60FC was decreased considerably and 25 percent of the added ammonium was accumulated. The average ammonium concentrations did not significantly vary among the levels of 50, 100 and 200 mg N kg-1, but these concentrations were significantly lower than those of 400 mg N kg-1. Moreover, EC and pH values of the soils were significantly increased and decreased in response to the nitrification (0.54 dS m-1 and 0.59 at the application level of 200 mg N kg-1, respectively). On average, the results showed higher nitrification (40.3 mg N kg-1) in the soil A (Loam texture) than the soil B (Clay loam).

Integrated Water and Nitrogen Fertilizer Management Using Modeling of System Dynamics Approach in Sugarcane Farmlands with Subsurface Drainage Systems
M.m. Matinzadeh, J. Abedi Koupai, M. Shayannejad, A. Sadeghi-Lari , H. Nozari,
Volume 25, Issue 4 (3-2022)
Abstract
Using water and fertilizer management at the farm level can be increased water use efficiency and reduce the volume of drainage water, fertilizer losses, and other pollutants in farmland with deep underground drains such as Khuzestan agro-industrial Companies. In the present study, a comprehensive simulation model for the water cycle and the nitrogen dynamics modeling was used for water and fertilizer management modeling on farmland of sugarcane in Imam Agro-Industrial Company using a system dynamics approach. To reduce irrigation water consumption and nitrogen fertilizer losses, five different scenarios were considered including four scenarios of water management consist of 5, 10, 15, and 20 percent reduction in the amount of irrigation water (I1, I2, I3, and I4) compared to the current situation of irrigation in Imam agro-industrial Company (I0), and one scenario of integrated water and fertilizer management (20% reduction in the amount of irrigation water and urea fertilizer 210 Kg/ha, I4F). The results of modeling showed that the scenario of I4F caused to reduce 31, 70, 71, 70, and 85 percent of the cumulative volume of drainage water, cumulative nitrate and ammonium losses, total losses of cumulative nitrate, and ammonium by tile-drain and cumulative losses of denitrification process, respectively. Thus, the implementation of this scenario, not only saves water and fertilizer consumption but also reduces environmental pollution effectively. So the scenario of I4F (amount of irrigation water for six months 2656 mm and urea fertilizer 210 Kg/ha) is recommended for sugarcane in the Imam agro-industrial Company.

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