farid feizolahpour; mehdi kouchakzadeh; fariborz abbasi; Mohammad nabi Gheibi; Rajab Choukan
Abstract
Introduction: Broadcast fertilization method increases fertilizer losses while results in lower nutrient absorption by plant roots. Fertigation is an effective method to increase water and fertilizer efficiency and to reduce the losses of nitrogen. Moreover, it allows farmers to apply the nutrients in ...
Read More
Introduction: Broadcast fertilization method increases fertilizer losses while results in lower nutrient absorption by plant roots. Fertigation is an effective method to increase water and fertilizer efficiency and to reduce the losses of nitrogen. Moreover, it allows farmers to apply the nutrients in splits and few amounts in response to crop needs. In the present study, a field experiment was conducted to investigate the effects of split application of fertilizer in furrow fertigation on nitrogen losses and corn yield.
Materials and Methods: Field experiments were carried out factorially in a randomized complete block design with four replicates. Experimental treatments were consisted of three fertilizer splits (two, three, and four splits) and three levels of urea fertilizer (60, 80 and 100% of required urea fertilizer), which compared with the common method (broadcasting fertilizer) as used by farmers in the fields. Experiments were conducted on a one hectare field in 120 meter long and open end furrows. During the crop season, Irrigation water was applied in the same way for all fertigation treatments and the third type of the WSC flumes was used to measure the amount of input and output water in irrigation events. Moreover, for determining the indexes of uniformity of water distribution in carrying out fertigation experiments, the amount of infiltration into the soil was calculated using the Kostiakov-Louis equation. The parameters of this equation were determined using the water volume balance method. Injection of Urea fertilizer was done by using 40-liter barrels were placed at the beginning of Furrows. In this study, the injection of fertilizers was applied in the last 10 to 20 minutes of irrigation time.
Results and Discussions: Results showed that water distribution uniformities of low quarter and low half in all tests were very high. Such that the water low quarter distribution uniformities for all treatments were between 90.5 to 98.3 percent and the low half distribution uniformities of water for different treatments were between 94.4 to 99.0 percent. So, according to the high water distribution uniformity and injecting fertilizer in 20-10 minutes at the end of irrigation, it should be stated that the distribution uniformities of fertilizer, used in the experiments, were high too. Statistical analysis showed that nitrogen usage amount and interaction of splits-usage rates of fertilizer had a significant influence on run-off nitrogen losses. The most nitrogen losses were achieved in treatment using 100 percent of fertilization recommendation and there were not significant differences between 60 and 80 percent of fertilization recommendation. It is nothworthy that, in addition to the nitrogen loss by surface runoff, nitrogen deep percolation losses always are also considered. In fertigation treatments, because of high rate of nitrogen injection in short intervals at the end of irrigations, the amount of nitrogen in the surface layer (20-0 cm) was significantly higher than the lower depths and this could led to low percolation losses of nitrogen, but the broadcast fertilization method provided the highest percent of remaining nitrogen in the soil after fertilization, which almost is unusable for plant and in the case of over irrigation or rainfall, the risk of groundwater pollution could be raised. Besides, the results showed that application of nitrogen in 4 splits provided more grain yield compared to the 3 splits level. Also, grain yield of corn increased significantly with increasing nitrogen rate application. The fertigation treatments had better performance of water and fertilizer application efficiencies compared to broadcast fertilization method. The most grain yield was achieved in the fifth treatment by application of 100 percent of fertilization usage recommendation in three splits.
Conclusion: In this study, the effect of furrow fertigation on nitrogen losses and corn yield was studied under different splits and amounts of fertilizer consumption. Eventually, fertigation treatments were compared with traditional treatments (fertilizer broadcasting method). According to the obtained results, evaluate the interactions of the effect of split × N usage showed that, the fourth treatment (60% of fertilizer application in 4 splits) can be suggested, owing to its lower N losses by runoff. In addition there were no statistical significant differences of grain yield between the fourth and fifth treatments (100% of fertilizer application in 3 splits). Consequently, it can be concluded that by the usage of 60 percent of the recommended fertilizer application in four equal splits during the growing season, the potential of environmental pollution will be reduced while achieving optimal performance.
foroogh abbasi teshnizi; M. Kouchakzadeh; F. Abbasi
Abstract
Water for agriculture is one of the most important factors in arid and semi-arid areas and municipal wastewater treatment is an important resource for this purpose. Therefore, potential of transfer contaminations is a serious problem regarding use of treated wastewater for agriculture. Due to the risk ...
Read More
Water for agriculture is one of the most important factors in arid and semi-arid areas and municipal wastewater treatment is an important resource for this purpose. Therefore, potential of transfer contaminations is a serious problem regarding use of treated wastewater for agriculture. Due to the risk of transfer contaminations through the use of wastewater, the study of transfer microbes in soil in recent decades has been of interest to researchers. In the present study, the transfer of bacteria fecal coliform was investigated in a lysimeter and the HYDRUS-1D model was used to simulate water flow and the fecal coliform in the soil. For calibration of the model and estimating the model input parameters, soil hydraulic and transport parameters, were inversely estimated. Results represented that the HYDRUS-1D with reasonably accurately simulated the outlet flow. To simulate the transfer of the bacteria in the soil, one site sorption model, two kinetic sites model (particle transport using attachment/detachment) and one kinetic site model were used. In the simulation of bacterial transfer, one site sorption model was selected as the proper model for this study. One site sorption model estimated solid-phase growth coefficient ( ) about sextuple more than liquid-phase. It showed that deposited cells had a higher division rate compared with the cell in liquid-phase. The calibrated model was used for surveying the effect various irrigation intervals and irrigation times on bacterial transfer. The results showed that by increasing irrigation times, more bacteria leached out from the soil. Also by increasing irrigation intervals, more bacteria observed in the soil profile, due to favorable environmental conditions and food for the bacteria growth. According to the results, the best interval and irrigation times were one day and four hours, respectively.
A. Khashei Siuki; B. Ghahraman; M. Kouchakzadeh
Abstract
Nayshabour plain in Khorasan Razavi with arid and semi-arid climate, have an important role in agricultural production by using groundwater resources. In this study, by using groundwater balance model the equations which are required for estimating water table variations is obtained for plain. afterwards ...
Read More
Nayshabour plain in Khorasan Razavi with arid and semi-arid climate, have an important role in agricultural production by using groundwater resources. In this study, by using groundwater balance model the equations which are required for estimating water table variations is obtained for plain. afterwards since, there are too many variables in the objective function of water consumption(optimized crop pattern and intensification) a meta heuristic method which require less computation of effect while it is more efficient will be used. In this research PSO optimization algorithm (Particle Swarm Optimization) is used. Model results based on a normal year (2008) showed that can earn highest income from the aquifer with 30 percent reduced spring cultivation, and increased 30 percent of wheat, barley and calona. Among the spring crops, corn and tomato ratio to another crops have largest increase area. The results showed that can obtain 7500 (thousands rial /hec)more benefit with increasing 20,591 hectares to autumn crops and reduced 10,970 spring products
