Document Type : Research Paper
Authors
1 Msc Student Irrigation and Drainage, Faculty of Agriculture, Bu-Ali Sina University of Hamedan;
2 Associate Professor, Agriculture Faculty, Bu-Ali Sina University of Hamedan;
3 Associate Professor, Faculty of Agriculture, Shahrekord University;
Abstract
Water stress and the limitation of plants water requirement have different effects on the underground organs growth indices. In this research, the effects of water stress on the growth of long green pepper root were studied in comparison with the regular method of irrigation in the greenhouse conditions. Irrigation treatments included 4 levels, viz. 40%, 60%, 80%, and 100 percent of the crop water requirement (CWR). At the end of the growing season, the root sampling was done and some of the root indices such as fresh and dry weight, root surface area and volume, length and root length density, and surface area to fresh weight ratio were measured for each treatment and compared with those of the control (100 percent CWR). Duncan's multiple range test showed that, with increasing irrigation water, the weight, volume, surface and root length increased. Therefore, all the studied indices in the 40 % CWR treatment were the lowest in comparison with the control treatment. Besides, in the 80 % CWR, decrease in fresh and dry weight of root was, respectively, 4.7 % and 31 %; in the 60 %CWR, fresh and dry weight decreased 10.5% and 47.7 %, respectively; and in the 40 % CWR treatment, fresh and dry weight of root decreased 25.7 % and 62.5 %, respectively, in comparison to the control treatment. Also, root surface and volume in the 80 %CWR decreased by 9% and 19.8 percent; in the 60% CWR treatment by 16.1% and33.8%; and in the 40 % CWR treatment by 25.8% and 47.3%, respectively, in comparison to the control treatment. The results showed that the root average growth in the control, 80%, 60%, and 40% CWR treatments reached the depth of 50, 48, 43, and 39 cm at the rate of 0.35, 0.33, 0.3, and 0.27 cm/day, respectively. The results of the three stress treatments showed that the reduction ratio of root traits in the 80% CWR was more appropriate compared with the other treatments. These results show savings in water consumption, which is important in terms of economic. Also, in all of the treatments, the amount of root length density decreased with soil depth penetration. In other word, most of the roots density was observed in the surface layer of soil.
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