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Objective: The use of nitrification inhibitor nitrapyrin is vital for long-term maintenance of urea fertilizer in the soil, preventing it from leaching. Therefore, this study tried to investigate the yield and physiological characteristics of different wheat cultivars under different levels of fertilization and tillage systems. Methods: The study was performed as a split-split plot based on a randomized complete block design with three replicates in Karaj during two cropping seasons (2019-21). The experimental treatments included two tillage levels (no-tillage and conventional tillage) as the main plot and three fertilizer levels (urea, nitrapyrin + urea combination and control (main plot), and two cultivars (Rokshan and Pishgam)) as the secondary plot. Results: The results of the composite analysis showed that the highest yield of wheat grain was obtained in Rakhshan cultivar with 8331 kg/ha and the level of urea + nitrapyrin fertilizer was obtained in no-tillage, being 6.15% superior to the level of urea. Also, in both tillage systems, the highest amount of leaf area index and nitrogen productivity index was obtained in the same treatment. Thus, compared to the treatment of urea application, 6.1%, 2.7% in no-tillage and 0.8% and 1.3% in Cultivation was more common. Conclusion: In general, nitrapyrin improved wheat yield in both tillage levels. In addition to improving plant performance, the use of nitrapyrin can also be effective in reducing environmental hazards caused by the use of chemical fertilizers such as urea. [ABSTRACT FROM AUTHOR]

As one of the most important food producers, the agricultural industry consumes a lot of energy to produce various products. Also, agriculture is the largest supplier of energy in the form of biological energy. This study was conducted in Khuzestan province with the aim of investigating the energy indicators of okra and the contribution of different inputs to the total energy in monoculture, intercropping (okra+cucumber) and agroforestry (okra+date palm) systems. The simple random sampling method was used to determine the survey volume and calculated sample size in this study was found to be 139. The data used in the study were collected from okra farms using a face-to-face questionnaire. The inputs and outputs were calculated per hectare and then, these input and output data were multiplied by the coefficient of energy equivalent. Following the calculation of energy input and output values, the energy ratio, energy productivity and net energy were determined. The results indicated that averages of energy inputs in monoculture, intercropping and agroforestry systems of okra were 78763.77, 81269.27 and 52502.42 respectively, while the energy output in these systems was 17575, 37380 and 113715 MJ ha-1, respectively. The energy ratio in monoculture, intercropping and agroforestry systems were calculated as 0.223, 0.460 and 2.166 respectively. The energy productivity in intercropping system was calculated as 0.470 kg MJ-1, which was about 302% and 64% more than monoculture and agroforestry, respectively. This issue is due to the higher yield of this cultivation system compared to other investigated systems. The results also indicated that energy inputs of plastic, diesel fuel and chemical fertilizers have the largest share of the total input energy in the investigated systems. To sum it up, for okra cultivation in Khuzestan province in non-agroforesty system, it is possible to recommend intercroping system by optimizing input consumption and reducing energy consumption, because it is superior to monoculture in terms of output yield. [ABSTRACT FROM AUTHOR]

In agriculture, nitrogen fertilizer does not effectively absorb by plants. Several biological activities in the soil convert N into various compounds. Nitrogen oxide (N2O) is an influential greenhouse gas formed in soils due to nitrification and denitrification process. Nitrapyrin (NI) combined with ammonium (NH₄⁺) based fertilizers is an effective technique for minimizing the N loss in agricultural soils by regulating ammonia-oxidizing. This research was conducted during 2019-2020 to determine the effect of NI on nitrogen emissions in soil and crop yield of wheat cultivars at three urea (UR) levels, NI+urea (NIU), and control (CO) on two cultivars (Rakhshan and Pishgam) and two tillage systems (No tillage (NT) and conventional tillage (CT)). The highest amounts of NH₄⁺, NO3- and N2O were found at the stem elongation stage. While NIU fertilizer treatment yielded the highest NH₄⁺ (18.38 mg kg⁻¹), the UR fertilizer treatment yielded the highest N3- (25.96 mg kg⁻¹) and N2O (0.0192 kg N2O-N ha⁻¹ day⁻¹). At all developmental stages in the CT and NT systems, the NIU treatment decreased the average nitrification of NH₄⁺ and its conversion to N3- by 27.81 and 15.45%, respectively. Our findings, thus, showed that NI application in conjunction with UR could highly reduce N2O emissions. In addition to the favorable economic impact, increasing N availability in the soil through minimizing nitrification by NI may reduce detrimental environmental consequences on water resources and greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Some essential factors effectively reduce wheat yield; one of the most critical factors is weeds. The effect of this factor can vary at different fertilizer levels. To investigate the effect of different densities of wild oat in different nitrogen fertilizer levels on the wheat traits, an experiment was conducted in the form of split plots and in a randomized complete block design with three replications. Treatments included the application of 30, 60, 100 and 120% of wheat nitrogen fertilizer requirement and densities of zero, 25, 50, 75 and 100 wild oat plants per m2. The results showed that the highest wheat grain yield (871.60 g/m2) and radiation use efficiency (1.49 g Mj-1) obtained at 120% fertilizer level and the absence of weeds, and the lowest obtained at 30% nitrogen and 100 plants per m2. The highest dry weight yield (381 g/m2) and radiation use efficiency (1.6 g Mj-1) of wild oats were obtained at 100 plants/m2 density and at the highest level of nitrogen fertilizer. In general, increasing the presence of wild oats and increasing its density under conditions of improper application of nitrogen can intensify interspecific competition and ultimately lead to yield reduction. [ABSTRACT FROM AUTHOR]