Increasing maize and sunflower seed yield using plastic mulch: an approach to optimum use of water

Drought is the most important abiotic stress in Iran, which leads to a significant decrease in plant yield. Crops need a lot of water. ‎Evaporation and transpiration determines the plant's water requirement. Water is one of the rare resources in Iran, which is affected ‎by the amount of rainfall. In Iran, the cultivation of maize has been greatly promoted in recent years, and its use in livestock and ‎poultry feeding and industrial uses has been noticed. Sunflower, as the main source of vegetable oil in the world, is of special ‎importance, which requires a lot of water. Plastic mulch is especially important in reducing water consumption in arid and semi-‎arid areas.‎An experiment was conducted as a randomized complete block design with three replications at the Research Farm, Agricultural ‎and Natural Resources Campus, Razi University, Kermanshah, Iran in 2016. The plants used in this experiment were maize and ‎sunflower. Treatments included plastic mulch between the rows, plastic coating on the plant (only in maize) and control (without ‎plastic). Treatments were applied at the beginning of the experiment and before germination.‎The plastic mulch between rows had the highest growth and yield of maize and sunflower than other treatments. In maize, plastic ‎mulch between the rows had higher biological yield, harvest index, number of seeds per row, ear weight, and 100-seed weight than ‎that of control, but there was no significant difference between plastic mulch between rows and plastic coating on the plant in terms ‎of mentioned traits. There was no significant difference among treatments in terms of number of rows per ear, ear skin weight, and ‎ear length. In sunflower, plastic mulch between rows had higher biological yield, head diameter, head weight, and 100-seed weight ‎than control, and there were no significant differences between treatments in terms of harvest index, and number of seeds per ‎head. ‎The results of this experiment show that by applying plastic mulch, especially ‎between the planting rows and before the seeds ‎germinate, while reducing the ‎length of the growth period and better use of moisture, the seed yield of maize ‎and sunflower can be ‎increased compared to not using plastic mulch by 38 and ‎‎41 percent, respectively. Other possible reasons for increasing grain yield ‎‎under the conditions of using nylon mulch included reducing evaporation and ‎increasing soil temperature at the beginning of the ‎growth period.‎