Effects of plastic film mulching on flax (Linum usitatissimum L.) root distribution and water use efficiency

film mulching%drought%soil profile%root growth%soil moisture%flax yield

To evaluate effects of plastic film mulching on soil moisture, majority root dis-tribution and water use efficiency (WUE), experiment was designed in flax field of Gansu, China. Three treatments including flat drill without mulching (CK), whole field soil plastic film mulched which covered with soil and bunch seeded (T1), and ridges mulched with plastic film and row-seeding in furrows (T2) were tested. Results indicated that mulching practice increased soil water storage compared to CK treatment in general. In both topsoil (0-30 cm) and underlying soil (30-100 cm) layer, T1 treatment had significantly greater (P<0.05) water storage than that in CK and T2 treatment. T1 treatment increased most significantly of soil water storage in 0-100 cm soil layer after rain, and also maintained high soil moisture at flax mature stage. Compared to CK, T1 and T2 produced obviously larger (P<0.05) taproot diameter and greater dry weight at both juvenile growth stage and first flowering stage, but had shorter lateral root length at all three stages. Consequently, seed yields and WUE with mulching treatment were increased by 22.3%-38.8% for T1 and 35.4%-56.2% for T2 com-pared to CK respectively. Film mulching is an effective cropping system for flax production in semiarid areas for improved root growth and enhanced soil moisture at different soil depths.