Study On The Appropriate Irrigation Amounts Of Eggplants In Autumn-Winter Crop In Solar Greenhouse

The planting area of eggplants（Solanum melongena L.）has been expanding year by year,and eggplants become one of the main vegetables for domestic sales and export earning foreign exchange in China.At present,during the process of facility vegetable production,fertigation technology of drip irrigation under plastic film has been widely applied,which is an effective measure to reduce water waste caused by flood irrigation,air humidity in facilities and improve the utilization efficiency of fertilizer and water.Under the climate conditions in Shandong province,there are few studies on the suitable irrigation amount of eggplants at different growth stages in solar greenhouse by using drip irrigation under plastic film.Therefore,in this paper,in order to find out the appropriate irrigation amounts at different growth stages of eggplants in autumn-winter crop and provide theoretical basis for high quality,high yield and high efficiency production of eggplants in solar greenhouse,the daily water demands of eggplants at different growth stages were studied under the conventional irrigation amounts(there was 200.48 m³·hm^-2,334.14 m³·hm^-2,451.08 m³·hm^-2and 350.84 m³·hm^-2respectively at seedling stage,flowering and fruit-setting stage,full fruit stage and harvesting stage every 15 days).Based on the above conventional irrigation amounts（as control,CK）,the effects of different irrigation amounts(reduced by 10%（T1）,20%（T2）and 30%（T3）on the growth and development,yield and quality of eggplants in autumn-winter crop in the solar greenhouse were studied using the’Bulita’eggplant as the test material,carried out the fertigation technology of drip irrigation under plastic film.The main research results were as follows:1.The daily water demands of eggplants in the autumn-winter crop in the solar greenhouse at the full fruit stage was 5.9 mm·d^-1,which is the maximum at the whole development stage;followed by 4.6 mm·d^-1 at the harvesting stage,4.0 mm·d^-1 at the flowering and fruit-setting stage,and 1.8 mm·d^-1 at the seedling stage.2.There was a correlation between environmental factors and daily transpiration rate variation in the autumn-winter crop in the solar greenhouse.At the seedling stage,the daily transpiration rate of eggplant leaves was negatively correlated with average air relative humidity during the day time,but there was no significant correlation of the daily transpiration rate of eggplant leaves with average air temperature and average light intensity during the day time.During the flowering and fruit-setting stage stage,the daily transpiration rate of eggplant leaves was positively correlated with the daily average temperature and daily average light intensity,and negatively correlated with the daily average humidity.During the full-fruiting stage,the daily transpiration rate of eggplant leaves was negatively correlated with the daily average humidity and positively correlated with the daily average light intensity.3.Under the treatment of reducing irrigation by 10%,the plant height,root activity,root surface area,leaf chlorophyll a,leaf net photosynthetic rate,water use efficiency,transpiration rate and stomatal conductance of eggplant were significantly higher than the control,respectively increased by 3.0%,18.7%,37.5%,15.3%,33.0%,23.0%,7.6%and12.1%.The activities of alkaline phosphatase,catalase and urease respectively increased by58.3%,5.8%and 22.9%.The number of bacteria,actinomycetes and fungi respectively decreased by 17.0%,16.2%and 20.0%.The content of available nitrogen,available phosphorus and available potassium respectively decreased by 3.0%,7.4%and 12.3%.4.Under the treatment of reducing irrigation by 10%,the contents of soluble sugar,soluble protein and free amino acid in eggplant fruits were significantly higher than the control,which respectively increased by 10.8%,12.3%and 6.7%.Under the treatment of reducing irrigation by 10%,the yield was 3.9%higher than that of control.Under the treatment of reducing irrigation by 20%,there was no significant difference between experimental group and control.Under the treatment of reducing irrigation by 30%,the yield was significantly lower than that of control.5.Under the conditions of this experiment,during the seedling stage,flowering and flowering and fruit-setting stage,full-fruiting stage and harvesting stage,the irrigation volume per 15 days of the eggplants is respectively 180.43 m³·hm^-2,300.60 m³·hm^-2,405.97m³·hm^-2 and 315.76 m³·hm^-2,eggplants have high yield and high quality,which can be used as a suitable irrigation quantity for autumn and winter stubble eggplant irrigation in the solar greenhouse in production.