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 ...
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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.
A.R. Heidary; R. Choukan; A. Tashakori; H. Kalantari
Abstract
Abstract
To determine the effects of different levels of drought stress on yield and yield components of corn hybrids as well as to determine the correlation between the characteristic and yield in different level of stress a experimental study was done in split plot with 15 corn hybrids placed in Gharakheil. ...
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Abstract
To determine the effects of different levels of drought stress on yield and yield components of corn hybrids as well as to determine the correlation between the characteristic and yield in different level of stress a experimental study was done in split plot with 15 corn hybrids placed in Gharakheil. the main plot was contained different levels of stress(a1:irrigation after 50mm evaporation from small tub evaporation. a2: irrigation after 90mm evaporation from small tub evaporatio. a3: irrigation after 130mm evaporation from small tub evaporation. a4:irrigation after 170mm evaporation from small tub evaporation. ) and sub plot contained corn hybrids. in normal ,mild and severe stress conditions OSGT14 hybrid respectively with 9. 445,9. 270 and 8. 352 ton/hac had the highest yield. in the severest stress condition SPGT12 hybrid with 7. 445 ton/hac had the highest yield. in the yield components, the weight of 1000 grains,the number of grains in rows,the number of grains in an ear of corn,biological yield,harvest indices and the geight and thickness of an ear of corn showed the most correlation with yield. . in other word,this characteries are having the most important effect on the yield. the correlation between tolerance indicies can be a factor in choosing the best hybrid and the best indices. where as there is a high correlation between MP, GMP, HARM and STI, in the other hand, these indices are having the highest correlation with yield in normal condition and different level of stress ,they can be called the most important indices. with the help of these indicies, probable delicate variaties can be distinguished.
Keywords: Drought stress, Corn, Tolerance indices
