Effects of partial root-zone irrigation on growth and development of maize root system
根区湿润方式对玉米根系生长发育的影响

Effects of partial root-zone irrigation on growth and development of maize root system from different root zones were studied using pot experiment. The pot was divided into two equal parts by a piece of plastic fixed in the central, which could prevent water penetration between two compartments, and maize was planted above the plastic so as to the root system to stretch into two compartments equally. Plants were irrigated on both halves of the container (conventional irrigation, C), on one side only (fixed partial root-zone irrigation, F), or alternatively on both sides (alternative partial root-zone irrigation, A). The results showed that after 40 d of treating, the ratios of root length to dry root weight and to root area increased markedly for the non-irrigated root zone of F treatment when compared to the ratios of the other root zones, suggesting that the root diameter becomes small in drought soil. The increase rates of root length, root area and dry weight were significantly enhanced for irrigated zones of A and F during 0-5 d of treating when compared to those of non-irrigated zones and C treatment. During 10-15 d of treating, the increase rates for the irrigated zone of A were significantly higher than those of any other zone while there was no significant difference between irrigated zones of F and C. For F treatment, both the values and increase rates of root length, root area and dry weight in the irrigated zone were always significantly higher than those of the non-irrigated zone. For A treatment, the increase rates changed alternately and the values became equal at the end of the experiment. Our results suggest that for A treatment, significant compensation mechanisms of root growth in irrigated root zone occurred both when water were localized in part of the root system, and during the subsequent recovery from drought stress. Moreover, A treatment was beneficial for root system to grow evenly in different soil zones.