Study On The Water Requirement Of Cucumber During The Whole Growth Period Of Greenhouse Cultivation

As the scale of facility agriculture has gradually expanded,more and more fresh water resources have been used.Since China is a serious water-deficient country,water-saving irrigation must be carried out in order to enable water resources to support the development of facility agriculture.In order to better study the water-saving irrigation of facility vegetables,it is necessary to conduct a lot of research on the water consumption rules of various stages of facility vegetables,so as to provide a strong theoretical basis for facility agriculture water-saving irrigation.In this paper,cucumbers under solar greenhouse cultivation conditions were used as research objects,and irrigation experiments were carried out.The meteorological factors,soil water content,leaf transpiration rate and cucumber growth traits in the experimental area were measured.The leaf transpiration rate,net photosynthetic rate and photosynthetically active radiation of different growth stages of cucumber were determined by CI-340 portable photosynthetic apparatus.The calculation formula of the required water requirement was used to determine the crop coefficient parameters.The principle of water balance and the transpiration rate of cucumber leaves were used to fit the variation of water requirement of cucumber with time.The research showed that:(1)Through the determination,the rationality of selecting the parameters of the cucumber crop coefficient under drip irrigation in the solar greenhouse was confirmed.And in the whole growth period of cucumber,the change rule of crop coefficient was consistent with the change rule of leaf area index,which was the first to increase,and then gradually decreased after reaching the maximum value in the result period.(2)There was a good correlation between the daily average temperature and the photosynthetically actived radiation intensity during the growth period of cucumber,and the temperature in the greenhouse increasesed with the effective radiation of photosynthetic line.Crop transpiration rate was affected by air temperature and photosynthetically actived radiation in the greenhouse,and there was a certain linear correlation between them.The transpiration rate of leaves increased with the growth of plants,and the transpiration rate at seedling stage was small.The minimum value was 1.4g*m-2*h-1.The transpiration rate during flowering and fruiting period was larger,and the maximum transpiration of the fruiting stage was entered.The rate can reached 5.71g*m-2*h-1,and the later transpiration rate began to decrease again,finally reaching 0.62 g*m-2*h-1(3)The change process of cucumber evapotranspiration during cucumber test was as follows: the evapotranspiration of cucumber in solar greenhouse increased with the growth of plants,and the variation range of seedling stage was small,ranging from 1.31 to 4.45 mm/d;The variation range of flowering and fruiting period was large,and the range of variation was 0.25~6.23mm/d.The later variation range of the fruiting began to decrease,and the range of variation was 2.85~5.62mm/d.The water requirement of cucumber has a good similarity with the change law of crop evapotranspiration during the whole growth stage.The water requirement of cucumber during the whole growth period started slowly in the early stage,and increased rapidly in the beginning of the fruiting period.Gradually decreasing trend.Among them,the water requirement during seedling period was less,the minimum value was 1.56mm/d,and the maximum water requirement at the peak period could reach 6.79mm/d.Then the water demand began to decrease,and the water demand at the end of the result was 1.643mm/d.