Effects Of Irrigation Depth Control On Root Morphology And Root Vigor Of Winter Wheat

The crop root can absorb and utilize water and nutrients from the soil, and its growth and development has a direct influence on crop growth and yield.Crop root is more sensitive to soil moisture content than other environmental factors. In order to study the effects of irrigation depth control on winter wheat root morphology and root activity, In the field of Shanxi conservancy technical college, using soil column cultivation methods to conduct the winter wheat root experiment. It designs four irrigation depth(TreatmentⅠis the ground irrigation,the irrigation depth of treatmentⅡis 60% of the depth of the root distribution,treatment Ⅲ is 75% of the depth of the root distribution, and treatment Ⅳ is90% of the depth of the root distribution). By measuring the root morphology,root activity and other relevant parameters of each soil layer of winter wheat, the experiment analysis the effects of irrigation depth control on winter wheat root morphology, root activity and drought tolerance. The results show that:(1)Compared to the ground irrigation methods, depth irrigation methods combined with soil moisture content can promote root depth plunging, improvetotal root length and weight, and significant effect its vertical distribution of root length density and weight density. It can improve the whole root biomass by promoting the growth of winter wheat in the lower soil layer. To maturity stage,depth irrigation methods can increase the root depth about 30 cm or so, the total root length about 20% or so and the total root weight about 10% or so. On the other hand, the depth of irrigation methods can make the deep root distribution in the soil tend to be relatively uniform.(2)For the depth irrigation methods, When at the early growth stages of winter wheat, the deeper of irrigation, the more of the whole root biomass; but at the later growing stages, excessive depth irrigation will have an adverse effect on the growth of root system, and it would result in a decrease of the whole root biomass. So it is necessary to select the appropriate irrigation depth, but the irrigation depth should not be too deep; Or at the later growth stages, increasing the amount of surface irrigation to meet the growth of superficial roots.(3)The soil moisture content of the root zone and the root morphology of winter wheat interact with each other. Within a certain range in soil layers, the greater of the soil moisture content, the larger of the root length density of the corresponding soil; But in turn, winter wheat root morphology will also affect the soil moisture content distribution of the root zone. Within a certain range in soil layers, the larger of root length density, the greater water absorbing capacity of the root, and the smaller of the soil moisture content in corresponding soil layers.(4)Compared to the ground irrigation methods, depth irrigation methods combined with soil moisture content had significant effect on the vertical distribution of root activity of winter wheat. It can significantly improve the root activity of the deep root, and sometimes it even can exceed the root activity of the surface root at the later growth stages. So that it can increase the root activity of the overall winter wheat; The proper depth irrigation methods can delay the aging process of winter wheat and slow down the decline rate of the root activity of the surface root at the later growth stages, making the overall winter wheat root system maintain a larger root activity.(5)The root vigor of winter wheat is closely related to its root length density. To the ground irrigation methods, at each growth stages, root length density and root vigor of winter wheat have a favorable positive linear correlativity. The greater of the root length density of winter wheat, the greater of the root vigor in corresponding layers; To the depth irrigation methods, at jointing and heading stage, root length density and root vigor of winter wheat have a favorable positive linear correlativity, but at booting and filing stage, due to the aging process of the surface root and the decline of root vigor. And the depth irrigation methods makes the root vigor of the lower root sharply increased, root length density and root vigor of winter wheat is not in conformity with the linear correlativity.(6)Compared to the ground irrigation methods, to the depth irrigation methods, the root-shoot of winter wheat is smaller; But the root-shoot are notproportional to its production. Depth irrigation methods can significantly increase the dry matter of above-ground apparatus, and then increased the production of winter wheat.(7)Compared to the ground irrigation methods, to the irrigation depth of60% and 75% of the root distribution in this test, on the one hand, it can make the winter wheat has a good root system configuration, and improve absorption capacity of the root and its water use efficiency, achieving the purpose of water saving. On the other hand, it can relieve the phenomenon of soil drought at the late growth stage of winter wheat and improve its drought-resistant ability. At the same time, the smaller root-shoot is benefit to dry matter accumulation of above-ground apparatus, and it can increase the production of winter wheat.Therefore, In this test, the irrigation depth of 60% and 75% of the root distribution are optimal irrigation depth that can improve the water use efficiency and drought-resistance ability of winter wheat. The experiment result can provide a reference for water-saving irrigation of winter wheat in North China.