The Study To The Parameters Of Non-Pressure Irrigation On Tomato In Greenhouse

Non-pressure irrigation has obviously water saving, production increasing and quality improving effects, and corresponding technical parameter is the safeguard to non-pressure irrigation superiority. This research is for the purpose of formulate suitable technology parameter for greenhouse tomato through mechanical experiment and field experiment, provides theory basis and technical support for non-pressure irrigation's popularize and application.The experiment carries on the greenhouse in Northwest A & F University dry area agriculture water and soil project ministry of education key laboratory from August 2005 to August 2006, and the test crop is tomato. Observed the wetting front shape, size and soil water content distribution rule under different technical parameter, measured soil water content dynamic change process, soil temperature and crops physiology ecology targets in different breeding stages, for example, net photosynthesis speed(Pn), transpiration rate(Tr), stomatal conductanc(eGs), root system resistance, leaf area index, plant height, stem diameter, dry matter cumulative, dry weight of different floor root system, fruit quality and so on, and computed the subdistrict total output.Analyzed the water supply pressures, the emitter diameters and buried depths influence to wetting front shape, size and soil water content distribution, obtained the wetting front shape is sphere, the soil water content get maximum near the emitter and symmetrically distribute taking emitter plane as symmetry plane; Under the condition of same irrigation volume, the water supply pressures influence the soil water content distribution, and the pressures are bigger, wetted volume, wetted distance in the radius direction and irrigated depth are bigger, the water distribution scope is bigger; Emitter diameter mainly influence wetted distance in the radius direction and irrigated depth, namely the diameter is bigger, the wetted distance in the radius direction is bigger, but the irrigated depth is smaller; After irrigation, the buried depth influence the wetted depth and wetted area in the surface soil, namely the buried depth is more shallow, the wetted depth is smaller, the wetted area in the surface soil is bigger; Buried depth influence the soil water directional distribution and air permeability in the surface soil, namely the buried depth is more shallow, the soil water content is bigger in the surface soil, and the air permeability is worse.The analysis and study to tomato growth condition under different technical parameter treatments indicated that: when the water supply pressure is zero, aperture 8mm is more advantageous than aperture 6mm to the crops growth; when the water supply pressure are 3cm or 6cm, aperture 6mm is more advantageous than aperture 8mm to the crops growth; when the aperture diameter is small (6mm), the tomato growth and the water supply pressure are positively related, but aperture 8mm is reverse. The pipe buried depth has regulation and induction to tomato root system growth, influence the root system gross and distribution in different soil horizon; Deepens along with the pipe buried depth, the allocation proportion of root weigh in the surface layer reduces in turn; In the early stage of tomato breeding, pipe buried depth influence root system's depth growth, namely the buried depth is smaller, root system's depth growth is more shallow; But in the tomato's middle and later stages, the root system stop downgrowth, and the pipe buried depth mainly influence root system's elongation scope in horizontal direction, more approach emitter is more advantageous to root system's growth; Pipe buried depth has significant effect on biomass cumulative, in the early breeding stage, pipe buried depth has small influence to dry matter's allocation in every organs, and tomato can harmonic growth in all treatments. In the later breeding stage, pipe buried depth influence dry matter's allocation in fruit and stem.The analysis about water supply pressure and emitter diameter's influence to tomato yield indicated that aperture 6mm treatments and 6cm pressure treatments get high yield; the study about pipe buried depth shows that when the buried depth is 10cm, tomato get the highest economic yield, water use efficiency and better fruit quality, and 10cm is the optimum buried depth to greenhouse tomato.Synthesized the experiment studies from 2005 to 2006 shows that the optimum technical parameter for greenhouse tomato is 6cm pressure, 10cm pipe buried depth, 6mm emitter diameter.