| Hot,dry,strong light and other factors seriously obstacle coffee arabica’s growth in its growing area of Yunnan.In addition,coffee arabica forms a habit of enjoying semi-shade environment in the long term systematic cultivation.Through combination of indoor experiments on moistube irrigation infiltration characteristics with water-light coupling experiments,this essay studies water distribution and change characteristics under moistube irrigation,explores the influence of moistube irrigation pressure heads and shade cultivation levels on coffee arabica’s physiological ecology and water utilizations,seeks the best coupling management mode of moistube irrigation pressure heads and shade cultivation levels so as to further improve efficient use theory of water and light.Moistube irrigation infiltration characteristics experiments(laboratory experiment)set three pressure heads:low pressure head(H1.0:1.0 m),medium pressure head(H1.5:1.5 m)and high pressure head(H2.0:2.0 m),and three soil bulk densities(D1.30:1.30 g·cm-3),mainly studies the influence of pressure head and soil bulk density on distribution of water and fertilizer in wetted soil.water-light coupling experiments(plot experiments)set three pressure heads:low pressure head(H1.0:1.0 m),medium pressure head(H1.5:1.5 m)and high pressure head(H2.0:2.0 m),and three shade cultivation levels:no shade cultivatio(S0:100%natural lighting),light shade cultivation(S1:65%～75%natural lighting)and strong shade cultivation(S2:45%～55%natural lighting),mainly studies the influence of moistube irrigation pressure head and shade cultivation density on coffee arabica’s physiological ecology and water utilizations.The main results of this study are as follows:(1)The water head and the soil bulk densities have significant effects on moisture,NO3--N and K+ content mean in moistube irrigation wetted soil.The wetted soil section area,NO3--N and K-distribution range increase as water head incease;the wetted soil section area,NO3--N and K+ distribution range decrease as the soil bulk densities incease,with K+ gathered around moistube.The moisture,NO3--N and K+ content mean and uniformity increase significantly in moistube irrigation wetted soil as water heads increase;the moisture and NO3--N content mean decrease significantly while K+ content mean increase slightly and water-fertilizer content uniformity decrease significantly as the soil bulk increase.moistube irrigation pressure head and shade level have significant effects on coffee root wetted soil moisture content mean.Compared with the laboratory experiment,wetted soil distribution range is larger under the same soil bulk density,the largest water content around moistube is lower.(2)Four parameters log-logistic model can reflect the regularities of distribution of the moisture.NO3--N and K+ content mean in the plot experiment and the laboratory experiment moistube wetted soil.(3)Compared with H1.0,Increased moistube irrigation pressure heads can respectively increase the plant height,stem diameter,crown breadth and the number of blades respectively by 2.06%～5.02%,5.81%～8.19%,4,31%～21.07%and 17.86%～25.00%.Compared with So,the plant height,stem diameter,crown breadth and the number of blades of S1 respectively increased by 20.31%,12.44%,24.45%and 52.00%while S2 increaed by 7.78%,4.61%,11.88%and 32.00%,which means relatively increased shade level can promote the increase of growth index of coffee,over-increased shade level can restrain the increase of the plant height,stem diameter,crown breadth and the number of blades.(4)Compared with H1.0,increased moistube irrigation pressure heads can respectively increase net photosynthetic rate,transpiration rate,leaf stomatal conductance,light use efficiency and water use efficiency by 222.10%～60.75%,28.02%～70.49%、11.58%～53.18%、35.51%～81.65%and 26.42%～39.61%while decrease leaf intercellular CO2 concentration by 14.16%～31.32%;Compared with S0,light shading S1 and heavy shading S2 increase respectively blade average daily Pn.Tr,Gs by 26.10%and 12.20%,26.28%and 5.37%,36.97%and 16.42%while decrease intercellular CO2 concentration by 5.88%and 11.97%;Si can respectively increase leaf blade daily light energy use efficiency and water use efficiency by 15.02%and 15.53%while S2 respectively decreased by 12,45%and 8.15%.In conclusion,through the contrastive analysis between the laboratory experiment and the plot experiment to consider growth and photosynthetic index,growth and water and light utilization promotion,the best water and light mode is pressure head and light Shade cultivation combination. |
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