Study On Water Demand Law And Recommended Irrigation Technology Of Areca

Areca is the pillar industry of Hainan Province.Due to the unique geographical location of Hainan Province and the traditional planting method of areca,the daily growth of areca can not meet the needs of water,Areca has many diseases and insect pests,leaf yellowing and other diseases.These problems lead to low yield,poor benefit and poor quality of areca.In order to achieve sustainable development of areca industry,we first took areca seedlings as test objects and set up different gradients of soil water content.Through testing the morphological and physiological characteristics of areca,we screened out soil water content suitable for the growth of areca seedlings.On this basis,the field experiment was conducted to investigate the water requirement of areca in different growth stages,the key period and critical period of water requirement by setting different irrigation amount to measure the soil water variation,daily water consumption,physiological characteristics,quality and yield of areca.The water demand of areca is found,which can promote the healthy growth of areca plants and alleviate the areca yellowing,which provides a theoretical basis for the cultivation and production of areca.The results of this test are as follows:1.The low soil moisture content makes the seedlings grow short,the leaf area decreases,the chlorophyll content decreases,the leaves turn yellow and the photosynthetic rate decreases,and the root activity is weakened.When the relative water content in soil is 55%～70%,the photosynthetic rate of areca is high and is beneficial to its growth.2.With the increase of irrigation amount,the soil mass water content increased,and the coefficient of variation of soil became larger.With the deepening of soil depth,the soil mass water content first increases,and then decreases when the soil depth is below 60～70cm.The coefficient of variation decreases with the deepening of soil layer.In each growth stage of areca,the soil evaporation in fruit stage is the largest,and the soil water storage also increases from flowering stage to fruit stage.The water storage of areca is negative in winter stage,which is the critical period of areca.Soil leakage and runoff increased with the increase of rainfall and irrigation.The annual leakage and runoff of areca accounted for 39.3%and 14.5%of the total rainfall and irrigation.The average annual water consumption of areca was 1101.8 mm,995.3 mm and 852.6 mm under the three treatments,respectively.The water consumption of areca reached the peak at fruit stage,and the water demand of areca was the largest at this time,which was the key period of water demand.3.The water use efficiency of areca leaves decreased with the increase of irrigation amount.The average water use efficiency of areca leaves in different growth stages was 2.0μmol·mol^-1,2.6μmol·mol^-1and 3.4μmol·mol^-1,respectively,and the WCK treatment had the highest water use efficiency.The water production efficiency and irrigation water production efficiency of areca reached the maximum in W50 treatment.4.The W70 and W50 irrigation levels significantly increased the leaf width and leaf area of areca,With the increase of irrigation amount,net photosynthetic rate and transpiration rate of areca leaves were increased,and chlorophyll water content of different kinds of areca leaves was increased.At different growth stages of Areca,the chlorophyll a,chlorophyll b and chlorophyll（a+b）of areca under W70 irrigation level were significantly higher than those of other treatments.The F_m,F_v,F_v/F_oand F_v/F_mwere the highest under W70 irrigation.The W70 treatment significantly increased the absorption of light energy per unit area（ABS/CS_o）and the number of reaction centers per unit area（TR_o/CS_o）.Under the irrigation level of this experiment,the yield and yield components of areca increased with the increase of irrigation water.The fresh weight of single fruit,fresh weight of single shuttle fruit,fresh weight of single fruit per plant and yield acre of W70 treatment were significantly higher than those of the other two treatments,which significantly increased the soluble sugar and fiber content of areca fruit.5.During the dry season from November to May of the next year,the healthy areca plants were irrigated with 8.3kg～8.7kg water per plant every 5 days,the normal areca plants were irrigated with 6.4～6.6kg water per plant every time,and the weak areca plants were irrigated with 4.0～4.2kg water per plant every time.