The effect of mulching on soil water storage and grain yields of maize and their mechanisms

Mulching was widely applied in agricultural activity of arid and semi-arid area.The micro-field trials(with rainproof) were carried out to investigate the effect of mulching on water storage and grain yields of maize in 2003 and 2004.In the trials,two tillage systems were designed including growing maize and fallow as main treatments.Every main treatment was divided into mulching and no mulching.The mulching material was wheat straw in 2003,and plastic film in 2004.The results showed that surface mulching of straw and plastic film increased the maize yield and water use efficiency as well.However,there was significant difference between wheat straw and plastic film.Plastic film mulching increased yield and water use efficiency significantly;straw mulching could increase the soil water conservation,but the yield increase was small.In fallow treatment,straw and film mulching conserved 10.2 and 7.4mm more water than bare land respectively in the 0～60 cm soil profiles.Under growing maize systems,straw mulching could conserve 16.1 mm more soil water than no mulching,and plastic film mulching consumed 13.0 mm more soil water than no mulching.While different mulching materials had different influences on nitrate distribution in the soil profile.Under fallow trial,soil nitrate content in the 0～40 cm soil profile with wheat straw mulching was lower than bare land,but it was higher with mulching of plastic film than no mulching;under planting systems,the nitrate content decreased in the 0～40 cm top soil of straw mulching and plastic film mulching compared to no mulching.