Effect Of Subsurface Drip Irrigation On Distribution Of Soil Moisture And Growth Of Turfgrass

Subsurface drip irrigation applying to turfgrass in turfgrass,which has a function of saving energy and water and has no effect on scenery because it was buried round the root of grass.An experiment has been conducted for investigating the rule of subsurface drip irrigation with two species of emitters:the flow passage of emitter and drip line for tall fescue;By carrying out the field test and indoor simulation test,discussed about soil moisture content,distribution of underground root and characteristic value of wetted solum.The results indicate that there is significant difference with horizontal soil moisture content to drip line and vertical soil moisture content to the flow passage of emitter.Flow passage of emitter had unconspicuous difference on distribution of soil moisture of horizontal and had high uniformity of irrigation,but drip line had significant effect on deep irrigation.The results showed that the wetted solum appeared in the shape of semi-elliptic cones both above and under the emitters.Remarkable power function relations were observed among horizontal,upwards vertical, downwards vertical wetting fronts and the infiltration time.Features of wetting fronts can be showed by this function.The size of distance of wetting front for drip line is downwards vertical,horizontal and upwards vertical.But the size of distance of wetting front for the flow passage of emitter is horizontal, downwards vertical,and upwards vertical.The result showed that the rate of wetting front in different directions is rising from 0°to 180°of observation because of the effect of gravity is stronger than press head.Because of the alternate effect of gravity and press head,the rate of wetting front is rising from 0°to 90°and declining from 90°to 150°, but rising again 150°to 180°.In order to guarantee enough irrigation for soil from 0 to 10cm,the depth of drip line is from 6 to 10cm,and the depth is from 10 to 15cm for the flow passage of emitter.According to the features of distance for horizontal wetting front and time,the intervals of drip line is between 30 to 40cm,and the depth is from 6 to 10cm and the intervals of the flow passage of emitter is between 50 to 70cm.There is significant difference with the rate of growth during returning green for tall fescue turf using subsurface drip irrigation,and there is unconspicuous difference with numbers of tillers and content of chlorophyll,so there is no visible effect on numbers of tillers and content of chlorophyll for using different emitters,depth and water diffuse equipment base on enough water for growth of turfgrass.There is significant increase for aboveground biomass,but no visible effect by using water diffuse equipment.Underground biomass keeps correspondingly stabilization,and root-shoot ratio staying in high level shows that turfgrass of tall fescue has good drought desistance for using subsurface drip irrigation.