Study On The Response Of Jujube Seedling Growth And Physiological Indexes To The Higher And Lower Limit Of Irrigation And Coverage

In this paper,we set three different up-down limits of irrigation and three types of surface cover,and then analyzed the effects of different irrigation lower limits and covering methods on soil surface temperature and daily water consumption,futher studying the response relationship between growth and physiological indicators of jujube seedlings under different treatments,in order to provide theoretical support and technical support for the cultivation of jujube seedlings in Hebei Province.The main conclusions are as follows:The effects of different irrigation up-down limits and covering modes on soil surface temperature were analyzed.Under the conditions of the up-down limits of different irrigation,the average ground temperature trends of the three types of coverage methods 0~15 cm are basically the same.The performance was as follows: In April,the ground temperature was the lowest,gradually increased with the climate change,reached the highest in July,and then stabilized;There is a characteristics that the average ground temperature in film coverage> that under straw cover>that in bare soil.According to the analysis of the diurnal variation of ground temperature under different treatments and different depths of typical weather,the average daily ground temperature of mulching film is higher than that of the other two cover types,which is more suitable for the growth of jujube seedlings.The following are the changes of water consumption of jujube seedlings in different phenological phases under different irrigation up-down limits and covering modes.At the up-down limits of irrigation,the water consumption patterns of all phenophases were consistent,namely: fruit enlargement period> fruit maturity period> flowering fruit setting period> bud emergence leaf period,and especially the high irrigation level treatment had the largest water consumption.Under different cover patterns,the order of water consumption from large to small was as follows: bare soil> straw mulching> covered with plastic film.It can be seen that during the process of cultivation of jujube seedlings,the film-covering measures can effectively reduce water consumption.The effects of different irrigation up-down limits and covering modes on the growth index of jujube seedlings were studied.The growth indicators included the height of the jujube head,the diameter of the plant,the diameter of the stem of the jujube head,and the area of the leaf.Compared with other treatments,the growth indicators performed best under the conditions of medium irrigation level(M2).The M2 model was most suitable for the growth of jujube seedlings.Among them,the growth rate of jujube head height first increased and then decreased during flowering fruit setting period,peaked at the fruit expansion stage,and finally reached a stable value;The growth rate of plant diameter first increased and then decreased after flowering fruiting period,afterward beginning to increase gradually during the fruit expansion period.At this time,the growth rate was the largest until the peak value;In the early stage of flowering and setting fruit,the growth rate of jujube head was relatively slow,and then gradually increased to the fruit expansion period,reaching a stable value;The leaf area grew fastest in flowering and setting fruit period,and the growth rate was the highest,then it gradually decreased.Although the growth rate has increased during fruit expansion,it has been growing slowly.The effects of different irrigation up-down limits and covering modes on physiological indexes of jujube seedlings were studied.In research,the chlorophyll content,Vitamin C content,and electrical conductivity of the leaves during fruit ripening were the best under M2 conditions compared to other treatments.Among them,the chlorophyll content of leaves and Vitamin C content were the highest compared with other treatments,and electrical conductivity was lower than those of other treatments.Study have shown that covering the film at the middle irrigation level can effectively preserve moisture and reduce water consumption,which is more conducive to promoting the growth of jujube seedlings.