Investigating Maize Root Growth Pattern under Partial Root Zone Drying (PRD) and Regulated Deficit Irrigation (RDI)

Plant performance and freshness is related to the pattern of its root growth development, which is highly affected by the water amount and water use management. Therefore, the spatiotemporal variation of maize root under five treatments including full irrigation treatment (FI), partial root-zone drying treatments at two levels (receiving 75% of ET =PRD75, and 55% of ET= PRD55) and deficit irrigation treatments at same levels (75% =DI75 and 55% =DI55) was investigated using a completely randomized block design in 2011. Root growth parameters including root volume, root area, root length, and root wet and dry mas were measured at each 10 cm soil depth interval down to 100 cm soil depth. Sampling locations were at 0.0 cm from the first lateral (R1), 18.75 cm (R2), 37.5 cm (R3), 55 cm (R4), and 75 cm (R5). Results demonstrated that FI treatment received 531 mm irrigation water while applying PRD75 and RDI75 caused 17.3% water saving during the whole growing season and applying PRD55 and RDI55 caused 31.3% saving. Analyzing the values of measured root growth parameters showed that the highest and the least values in all samples were in PRD75 and RDI55 treatments, respectively. Also, most part of the root was distributed in 0-20 cm soil depth and up to 20 cm apart in both sides of the plant. The least values of root growth parameters were at 50-60 cm soil depth in RDI treatments and at 60-70 cm soil depths in PRD treatments. Also, results demonstrated that there was no significant difference between the measured values of root parameters in PRD75 and RDI75 with those in FI treatment. Therefore, applying PRD75 and RDI75 caused both water saving and an optimum root development, which led to a better utilization of soil water content under water stress. Thus, both RDI75 and PRD75 treatments are appropriate strategies to deal with the water shortage and to reach a sustainable agriculture.