Water Consumption Characteristics And Root Distribution Of Wheat Corn Intercropping Systems In Oasis Area

Wheat corn intercropping is one of a widely used highyield multiple cropping pattern in Hexi Oasis Area of Gansu Province.However,being the serious shortage of natural water resources,the application of intercropping is decreasing continuously in recent years,and the arable land productivity is decreasing simultaneously,so opening up high efficient water-saving theory and technology for intercropping has become big chanllenge in multiple cropping research area.In this study,a field experiment was carried out in typical oasis area,in order to investigate the effect of root interaction on the yield and water use efficiency(WUE) of wheat corn intercropping system.Three kinds of root separation were cobined in the intercropping systems,and the Micro-Lysimeters were used to measure the soil evaporation.The relationships between root distribution characteristics,soil water content, leaf area index and WUE of crops was discussed finally.The main results showed as following:1.Compared with single cropping systems,wheat-corn intercropping is promoted theland equivalent ratio and the water use efficiency.and roots iteraction plays an important role in improvind the yield and WUE of intercropping.separation makes influence on the improvement of intercropping yield performance and WUE,and intercropping is able to promote the land-use efficiency.LER of Non-root-separation(W//C),wheat corn intercropping that root separated by plastic film(PW/C),wheat corn intercropping that root separated by nylon(NW/C) are 1.46%,1.20%and 1.39%.Compared with single-planted wheat and single-planted corn,the yield performances of W//C,PW//C,NW//C have been raised by 76.2%,46.2%,7.9%,and 25.4%,4.1%,19.5%, which shows that the influence of root separation is greater on wheat yield performance than that of corn. PW//C remarkably lows the W//C intercropping.PW//C compared between W//C,NW//C,the yield performance lows as 20.5%,14.8%,which demonstrates that the contributive proportion of root affection of W//C is 17.0%,while that of spatial root intersection is 4.7%.WUE of W//C,PW//C,NW//C are higher than the weighted average of single planted wheat,and single planted corn,performed as 51.90%,25.94%, 43.04%.WUE of W//C compared with PW//C,NW//C is higher by 17.1%,5.8%.Root separation lows WUE of intercropping.The contributive proportion that root intersection performs on WUE of W//C is 17.1%,while that of spatial root intersection is 5.8%.2.The planting model makes influence on the water consumption of wheat and corn in their whole growth period.Root separation makes a smaller influence on the water consumption of wheat corn intercropping,a greater influence on evapotranspiration.Compared with the weighted average of sole wheat and corn WUE,WUE of W//C,PW//C,NW//C are increased seperately by 3.24%,3.00%,1.81%.And the divergence of the three dates is not obvious.The total evapotranspiration of W//C,PW//C,NW//C is higher than that of the weighted average of the single planted evapotranspiration as 44.1%,31.3%,41.0%.The evapotranspiration of W//C is higher than that of PW//C and NW//C,by 8.9%and 2.2%.The influence of root affection on the evapotranspiration of W//C is 8.9%,while which of spatial root intersection is 2.2%.The proportion of WUE of the evapotranspiration of both single planted wheat and corn,and the three kinds of intercropping is 18.2%,12.2%,22.0%,20.0%, 21.2%.In a word,intercropping enlarges the proportion of evapotranspiration.3.Intercropping makes influence on the temporal and spatial distribution of the root systems of wheat and corn,and makes a superposition of the use of underground soil space in different periods.During the period of W//C commensalism,in W//C,the vertical distribution area of wheat root is smaller than that of the single planted wheat.The density of W and W//C root weight(g/500cm3) is 0.02,and the equivalence lines are about 70cm and 60cm.The density of PW//C and NW//C root weight(g/500cm3) is 0.02,and the equivalence lines are about 80cm and 75cm,which is higher than that of the single plangtation.The sidelong distribution of W//C occupies and makes use of most of the space of the underground part of the two intercropping plants,and the root system of 0.02 in root weight density grow crosswise into the root system of corn by 20-40cm.The corn root system only occupies a small part of the space.When corn has been into the filling stage,corn in W//C occupies and makes use of underground soil space,and enlarges its effective space of absorbing the nutrients both vertically and laterally,and its root system occupies the whole profile of the wheat root laterally.In various conditions,root separation methods make influences on the root weight density and downward depth of wheat.Non-root-separation root weight density is higher than that of root separation.Between the two different separations,root weight density in NW//C is higher than that of PW//C,and the contributive proportion that root intersection makes on W//C root dry weight is 36.6%,while it is 28.5%of spatial root intersection.Root dry weight makes an obvious positive relevance with WUE.The root dry weight of wheat of 20-40cm makes an obvious positive relevance with the yield performance.