Environment Characteristics And Regulation Measures Effect Of Hongmeixing Apricot Orchard In The Southern Mountains Of Ningxia

Extensive management of orchards in the Southern Mountains of Ningxia,the fruit trees such as Hongmeixing apricot grow weak and have poor frost resistance,resulting in low yields of fruit trees and insufficient economic income of fruit farmers,which is not conducive to sustainable social and economic development and ecological environment construction in the Southern Mountains of Ningxia.This paper analyzes the environment characteristics of Hongmeixing apricot in the southern mountainous area of Ningxia,explores the main limiting factors in the growth of Hongmeixing apricot,and studies the effects of apricot orchard regulation measures on the problems of late frost damage at flowering time and the high cost of existing prevention and control.The 12-year-old Hongmeixing apricot orchard was used as the test garden in the southern mountainous area of Ningxia from 2018 to 2019.Taking the ground clearing,no covering and no irrigation measure of local apricot orchard as the control,adopting ground regulation measures with low economic cost(straw mulching,black ground fabric mulching,irrigation,irrigation+mulching,irrigation+black ground fabric mulching)to improve the growth of apricot trees,delay the phenological period of flowering and fruit setting time,reduce frozen flowers and frozen fruits,and select the best regulation measures from them.The main conclusions are as follows:(1)The temperature range in spring is large in the Southern Mountains of Ningxia,and the damage of late frost is frequent,which is the most direct external factor for the large-scale reduction or failure of Hongmeixing apricots in the area;The lack of water and fertilizer management and the absent shaping and pruning in the growth process,apricot tree grows naturally,the tree vigor is weak,fruit-bearing branches was aging,and with poor stress resistance and the lower fruit-setting rate were the main internal factors for the poor yield or failure.The study found that the soil gravimetric water content of the apricot orchard(12.76%)in the 0-400cm soil layer less than that of the farmland(17.66%)by 26.49%,and the apricot orchard significantly consumes deep soil moisture.In addition,the soil organic matter(6.93 g·kg-1),total nitrogen(0.51 g·kg-1),alkali-hydrolyzale nitrogen(40.57 mg·kg-1)and available phosphorus(5.61 mg·kg-1)in 0-60 cm soil layer of the apricot orchard are also in deficit.The soil moisture and fertilizer conditions in this area have been difficult to meet the normal growth needs of apricot trees.Therefore,water and fertilizer management should be strengthened in this area,tree vigor should be enhanced,and the tree's resistance to stress should be improved.(2)At the same depth of soil layer,the content of soil organic carbon and total nitrogen in the soil of apricot orchard was lower than that of farmland in the Southern Mountains of Ningxia,while the content of total phosphorus was higher than that of farmland.The soil C:N ratio(7.89-8.08)in orchard increased with the depth of the soil layer,and the soil C:P ratio(5.95-6.47)and soil N:P ratio(0.73-0.82)were much lower than the soil average of China(61.00 and 5.20),indicating that the total phosphorus content in the soil of apricot orchard in the Southern Mountains of Ningxia is relatively high.The leaf N:P ratio and root N:P ratio was 25.93(>14)and 8.06(<14),respectively,which indicated that the leaf growth of apricot trees in this area was mainly restricted by phosphorus,while root growth was mainly restricted by nitrogen.(3)Compared with the control,from March to August 2018 and May to August 2019,the various ground regulation measures decreased the daily average temperature of 0-40 cm soil layer,in which the average daily temperature of soil was the lowest by irrigation+straw mulching.And from March to May 2018,the soil temperature covered by straw was lower than that covered by black ground fabric.From December 2018 to February 2019,the daily average temperatures of the 0-20 cm soil layer under different ground regulation measures were higher than the control.The temperature in the 0-20 cm soil layer covered by the black ground fabric was higher than that of the straw mulching.In 2018 and 2019,various ground regulation measures have increased soil water storage.Among them,the soil water storage covered by black ground fabric was higher than that covered by straw,but the soil water storage covered by irrigation+straw mulching was higher than that of irrigation+black ground fabric mulching.(4)Black ground fabric mulching,straw mulching and irrigation+straw mulching all delayed the flowering period of Hongmeixing apricot,and the flowering period of black ground fabric and straw mulching were delayed by 1 day.Irrigation and irrigation+black ground fabric mulching did not have a significant delay effect on the flowering period of Hongmeixing apricot,but the flowering period were prolonged by 2 days.The flowering period of irrigation+straw mulching was delayed by 2 days,and the entire flowering period was prolonged by 2 days.Compared with the control,all the ground regulation measures have improved the tree vigor,increased the complete flower proportion and fruit setting rate of Hongmeixing apricot.The effect of the combination of irrigation and mulching on improving fruit setting rate is higher than that of single mulch or single irrigation.(5)Different ground regulation measures have improved the quality and yield of Hongmei apricot.The effect on the appearance quality of Hongmeixing apricot is that the effect of irrigation was better than that of non-irrigation.Different ground regulation measures all increased the content of soluble solids of Hongmeixing apricot,which irrigation+straw mulching had the highest vitamin C content and the titratable acid content was reduced by 34.51%.Irrigation+straw mulch promoted the tree vigor,and single fruit weight and yield effects were increased by 3.59 g and 5.02 kg tree-1 compared with the control.