Study On The Root Distribution Of Ziziphus Jujuba And The Relationship Between The Distribution And Soil Water And Nutrients In Hillside Fields

Ziziphus jujube which is native to China becomes one of the particular economic species of China. Moreover, it is also one of the typical fruit in semiarid areas of Loess Plateau region. Under drought condition, reasonable irrigation can change the soil water environment of Ziziphus jujube plantation, influent the root distribution and promote the root absorption of water and nutrient. So the study about the combination of the root distribution and irrigation is meaningful to reveal the increasing production mechanism of Jujube plantation and manage water and fertilizer efficiently.In this study, we employed the digging methods from left to right and from up to down to investigate the root special distribution of Ziziphus jujube. And the purpose of this study was to obtain the effect of dripping irrigation and soil water and nutrient on the spatial distribution of roots and master the root distribution of Ziziphus jujube in natural and dripping irrigation condition respectively. We expected to provide reference to improve the efficiency of irrigation and feasible irrigation methods for jujube plantation. The results were that:(i) The root of Jujube tree included horizontal root, vertical root, unit root and fine root. And it trended to grow in the environment with rich water, fertilizer and air. The weight of conductive root (d>2mm) occupy for 89.05% of total root weight and the absorbing root (d≤2mm) was only 10.95%;(ii) The fine roots were mainly concentrated in the 0-40cm soil layer and in the scope from 0 to 30 from stem which contained the richest soil moisture and fertilizer. And the weight of absorbing root and soil moisture were inversely correlated typically;(iii) In the horizontal direction, the distribution of Jujube root length density presented a typical negative exponential type and the distribution of Jujube root weight density presented a typical parabola model. And in the vertical direction, the effective root weight density and length density presented a power function and decreased firstly and then increased with the increasing of soil depth. Regression estimate of non-linear parameter showed that model whose equation is RD=eA+BX+CZ is a good way for simulating the spatial distributions of the effective root length and weight density;(iiii) The absorbing root biomass and root length density had notable correlation with effective soil nutrient. And no significant correlation was found between root length and soil nutrient. The increase of soil nutrient can promote the biomass of absorbing root and root length density especially the increase of available P and available K;(iiiii) Drip irrigation could increase the total root quantity, total root absorption and total amount of conducting root of the jujube, however, there was obvious area restrictive to the growth of absorbing root of the jujube by taking drip irrigation, absorbing roots length less than 2 mm consisted main root system to absorb moisture and nutrients. Increase of the quantity of absorbing root improved absorption ability of water and nutrient of the jujube under the condition of drip irrigation.