Luxury transpiration of winter wheat and its responses to deficit irrigation in North China Plain

Reducing crop luxury transpiration is an important step in improving water productivity; water shortage regions are potential hotspots for studying physiological water conservation. This study investigated the amount of luxury transpiration in winter wheat and its responses to different irrigation treatments in North China Plain. The results showed that luxury transpiration existed and increased with growth of winter wheat and after rainfall. In each sampling day, the amount of luxury transpiration under full irrigation was significantly higher than that under deficit irrigation. The average amount of luxury transpiration was 258.87 g/m(2) under full irrigation, and 125.18 g/m(2) under deficit irrigation during the experimental period. Although the amount of luxury transpiration was 2.09-fold higher under full irrigation than that in deficit irrigation, the water loss ratio due to luxury transpiration in deficit irrigation (8.13%) was significantly higher than that in full irrigation (6.75%). Furthermore, the ratio between luxury transpiration amount and crop daily transpiration was revealed in all sampling dates. Therefore, deficit irrigation should be generalized in the water shortage area, because it can save irrigation water and reduce the amount of luxury transpiration. Full irrigation should be carried out in the water abundant region mainly for higher production.