بررسی تأثیر سطوح مختلف آبیاری قطره‌ای (تیپ) بر عملکرد و اجزاء عملکرد ذرت دانه‌ای

Introduction: One of the serious problems in the further development of maize cultivation is increasing irrigation efficiency. Using conventional irrigation causes a shortage of water resources to increase the acreage of the crop. With regard to the development of maize cultivation, agronomic and executable methods must be studied to reduce water consumption. Using drip irrigation system is most suitable for row crops. Hamedi et al. (2005) compared drip (tape) and surface irrigation systems on yield of maize in different levels of water requirement and indicated that drip irrigation increases the amount of yield to 2015 kg/ha and water use efficiency to 3 time. Kohi et al. (2005) investigated the effects of deficit irrigation use of drip (tape) irrigation on water use efficiency on maize in planting of one and two rows. The results showed that maximum water use efficiency related to crop density, water requirement and planting pattern 85000, 125% and two rows, respectively with 1.46 kg/m3. Jafari and Ashrafi (2011) studied the effects of irrigation levels, plant density and planting pattern in drip irrigation (tape) on corn. The results showed that the amount of irrigation water and crop density on the level of 1% and their interactions and method of planting were significant at the 5 and 10% on water use efficiency, respectively. The yield was measured under different levels of irrigation, crop density and method of planting and the difference was significant on the level of 1%. Lamm et al. (1995) studied water requirement of maize in field with silt loam texture under sub drip irrigation and reported that water use reduced to 75%; but yield of maize remained at maximum amount of 12.5 t/ha. The objective of this study was to evaluate the drip (tape) irrigation method for corn production practices in the Qazvin province in Iran.
Materials and Methods: In this study, yield and yield components of corn (SC 704) were investigated under different levels of irrigation water in drip tape systems in one and two rows planting patterns with different plant densities. The experiment was conducted on randomized complete blocks as a split plot (Split block) design with 3 replicates in the Qazvin region. Four levels of irrigation including: 80, 100 and 120 percent of water requirement with drip irrigation (tape) and 100% water requirement with furrow irrigation (control treatment) as main plots and method of planting (one and two rows) with three levels of crop density including: 75000, 90000 and 105000 as subplots were considered. After harvesting, grain yield, number of rows per ear, number of kernels per ear row, number of grains per ear and 1000-kernel weigh were measured.
Results and Discussion: The results of simple variance analysis of attributes showed that the method of planting has a significant difference on the level of 5% for grain yield, but on the other the measured attributes did not have any significant effect. The respective effect of planting method and crop density showed a significant difference on the level of 5% for grain yield, number of kernels per ear and the 1000-grain weight, whereas it did not have any significant effect on the other measured attributes. The respective effects of irrigation method, planting method and crop density showed a significant difference on the level of 1% for the attributes of the number of kernels per ear. The planting in one row resulted in significantly higher grain yields than the other planting patterns. In mean comparisons of the interactions between irrigation methods, crop density and planting method, grain yield in drip irrigation at a level of 120% water requirement in the two rows planting pattern and crop density equal to 75000 plants was shown in the lead on the level of 10%. The results showed that the yields of the treatments were only affected by the method of planting and planting of one row lead the planting of two rows. According to means comparison and water use efficiency in each of the treatments and limitation of water resources, one row planting pattern with crop density equal to 90000 under drip irrigation at 80% and 120% (If there is no water restrictions) of water requirement were suitable.
Conclusion: According to the table of variance analysis, it can be seen that the effect of irrigation on corn grain yield was not significant. Research results of Sorensen and Butts (2005) and Azari et al. (2007) have also confirmed this subject. The grain yield in one row planting method was superior compared to two rows planting method. The superiority of one ton per hectare was statistically significant and substantial. Grain yields varied from 5360 to 12873 kg/ha among the treatments: in drip irrigation at a level of 120% water requirement in the two rows planting pattern and crop density equal to 75000 plants per hectare was 12873 kg/ha and the lowest yield was found in drip irrigation at a level of 80% water requirement in the two-row planting pattern and crop density equal to 75000 plants per hectare as 5360 kg/ha. With regard to mean comparisons of grain yield under the effects of interaction, and water use efficiency for each treatments, I1R1D2, I3R1D2, I1R1D1 and I2R2D3 treatments seem better than others.