Study On Precision Irrigation Scheduling Of Lycium Barbarum Based On Root Restriction Cultivation

As a local economic crop,Lycium barbarum has become one of the important industries for farmers in the arid areas of Northwest China to get rid of poverty and become rich.However,the traditional deep-hole planted Lycium barbarum root system was often larger than the canopy,which makes fruit trees have low water and fertilizer utilization and difficult water and fertilizer control.However,irrigation water resources in Northwest my country were scarce.Under the background of the country’s vigorous promotion of water saving,the development of cultivation methods the irrigation mode of Lycium barbarum planting combined with water-saving irrigation was of great significance.To this end,this paper firstly conducted a simulation experiment of drip irrigation soil moisture infiltration under the condition of indoor root zone restriction(restricted infiltration zone),studied the law of soil moisture migration of drip irrigation under restricted infiltration zone,and initially determined some drip irrigation technical parameters(such as Dripper flow,etc.);secondly,on this basis,taking Ningqi "No.7" as the research object,through the field root zone restriction cultivation conditions drip irrigation Lycium barbarum planting experiment,further analysis of the root zone restriction and irrigation quota on the growth,According to the influence of the law of yield and water consumption,the drip irrigation system of Lycium barbarum under the condition of root-limited cultivation was proposed,in order to provide a certain reference for the popularization and application of the root-limited Lycium barbarum drip irrigation technology.The main conclusions are as follows:(1)The law of soil water movement in drip irrigation under restricted infiltration area was studied.It was found that after soil moisture infiltration reaches the restricted boundary,the restricted infiltration zone would reduce the soil moisture infiltration rate.Compared with the treatment of the unrestricted infiltration zone,the infiltration rate was reduced by 2.30%-40.38%.After the irrigation was completed,the shape of the wetting body would be reduced.The size was consistent with the shape and size of the restricted infiltration area.Because the soil water was kept within the restricted infiltration range,deep leakage was reduced and the water utilization rate was improved.The flow rate of the emitter has a great influence on the process of soil water infiltration and its redistribution.In the initial stage of irrigation,the larger the dripper flow rate,the greater the soil moisture level infiltration rate.The soil moisture level infiltration rate with a dripper flow rate of 4 L/h increases by 11.07%～28.25%compared with a dripper flow rate of 3 L/h;At the end of irrigation,the larger the dripper flow,the smaller the vertical infiltration distance of soil moisture.The vertical wet front transport distance of the dripper with a flow rate of 4 L/h is reduced by 4.85%～11.86%compared with the dripper flow rate of 3 L/h.(2)The effects of root zone restriction and irrigation amount on the growth,photosynthetic characteristics,yield and water consumption of Lycium barbarum were analyzed.It was found that the root restriction conditions can inhibit the growth of lycium barbarum plant height and ground diameter,and the smaller the root-limiting width,the more obvious the inhibition effect.The increase in plant height of Lycium barbarum with root-limiting widths of 40 cm,60 cm and 80 cm was 0.5～0.6 times,0.5～0.6 times and 0.9～1 times that of conventional cultivation treatments,respectively,and the increase in ground diameter was higher than that of conventional cultivation treatments smaller 33.3%～52.4%.However,the restricted conditions of the root zone could increase the net photosynthetic rate of Lycium barbarum leaves and the number of flowers of Lycium barbarum to a certain extent,thereby increasing the yield of Lycium barbarum.Under the same irrigation conditions,the net photosynthetic rate,the number of flowers and the yield of Lycium barbarum leaves increased first and then decreased with the increase of the limited root width,and the net photosynthetic rate and the number of flowers of the treatment with the limited root width of 60 cm.And the output was the largest,respectively 1.0～1.2 times,1.3～3.1 times and 1.3～2.5 times of conventional treatment.The plant height,ground diameter and yield of Lycium barbarum showed a parabolic change trend with the increase of irrigation volume.When irrigation volume was 315 mm,the indexes were the largest,which were 16.61 cm,0.27 mm,and 11627.40 kg/hm2,respectively.When the irrigation volume was 315 mm and the root-limiting width was 60 cm,the irrigation water use efficiency and water use efficiency of Lycium barbarum were as large as 2.042 kg/m3 and 3.691 kg/m3 respectively.(3)The drip irrigation scheduling of Lycium Barbarum under the condition of restricted root cultivation was proposed.Comprehensive analysis of factors such as Lycium Barbarum growth,yield,irrigation water use efficiency and water use efficiency.It was more suitable for Lycium barbarum to be planted with a root restriction width of 60 cm in the experimental area.,The drip irrigation scheduling(precipitation frequency is P=75%)of Lycium barbarum was as follows:irrigation quota of 315 mm,a total of 14 times irrigation during whole growth period,germination period(late April)1 irrigation for a total of 30 mm,spring shoot growing period(early May)2 irrigations for a total of 40.5 mm,first flowering period(mid May to late May)2 irrigations for a total of 33 mm,fruit mature period(early June to late July)6 irrigations for a total of 126 mm,autumn fruit period(early August to early September)2 irrigations for a total of 40.5 mm,dormant period(late October to early November)a total of 45mm in 1 irrigation.