Plastic film mulching with drip irrigation promotes maize (Zea mays L.) yield and water-use efficiency by improving photosynthetic characteristics

摘要

It is important to reveal the physiological mechanism of water saving and yield increasing of mulched drip irrigation. Three treatments were applied at aspring maize field in Northeast China: mulched drip irrigation (MD), non-mulched drip irrigation (ND) and rain-fed practice (CK). Result showed that, MD treatment increased 5-year (2014-2018) average grain yield (GY) by 18.6 compared with the CK. The GY showed significant linear positive correlations with photosynthetic capacity (A(max)) and maximum carboxylation rate (V-cmax). The 2-year (2017-2018)mean A(max) and V-cmax of MD were significantly increased by 21.1and 10.7, respectively, compared with CK, and the increase was partially contributed by the descending of bundle-sheath cells to CO2 (L). The L of MD was decreased by 6.5-12.4 (P< 0.05) during the jointing and tasseling-milk stages. The relationships between A(max) and leaf nitrogen content (N-mass), and between V-cmax and N-mass, were affected by mulching treatment, which indicates that the higher leaf Nuse efficiency of the MD treatment. This study provides atheoretical basis for implementation ofmulched drip-irrigation technology,especially in Northeast China.