Effects of intermittent irrigation on ecological and physiological water requirement of rice in north China
间歇灌溉对北方水稻生理生态需水的影响

The ecological and physiological water requirement of rice was studied in a paddy field of north China,and the field experiment was conducted at Shenyang Experimental Station of Ecology,Chinese Academy of Sciences.Under continuous flooding irrigation(CSF) and intermittent irrigation(IT) conditions,the evapotranspiration and soil evaporation of paddy fields were measured by non-weighing lysimeters and micro-lysimeters,respectively.The results showed that compared with continuous flooding irrigation,the transpiration under intermittent irrigation condition was not significantly reduced,but 16% and 24% of water amounts were reduced by decreasing the water losses through soil water evaporation and percolation,respectively.The water use efficiency of intermittent irrigation was increased 10%,without any adverse effects on biomass and grain yield of rice.Although the amount of water requirement under IT treatment was reduced significantly compared with CSF treatment,about 60% of total water requirement was still lost through deep percolation.Based on the results obtained,the corresponding countermeasures to reduce the amounts of soil water evaporation and percolation and to increase the water use efficiency were put forward in this paper.