Site description
This study was conducted at National high quality red plum apricot demonstration area,which is located at the Shanghuang Eco-experiment Station in the semiarid Loess hilly region (35°59′- 36°02′ N, 106°26′- 106°30′ E) in Guyuan, Ningxia Hui Autonomous Region of China, Institute of Soil and Water Conservation of Chinese Academy of Sciences, with the altitude of the station ranges from 1,534 m to 1,824 m. Precipitation here is absent in the periods from January to March and from October to December, and the rainfall from June to September makes up more than 70% of the annual precipitation. Mean rainfall measured between 1983 and 2001 was 415.6 mm with a maximum of 635 mm in 1984 and a minimum of 260 mm in 1991. The frost-free season is 152 days. The Huangmian soil having developed directly from the loess parent materials, consists mainly of loamy porous loess (Calcaric Cambisol, FAO1988) with wide distribution in the semiarid hilly region of the Loess Plateau. Red plum apricot tree is a kind of fine variety apricot (Armeniaca vulgaris Lam.). The experiment was conducted in 23-year-old red plum apricot garden planted in 1996 and 1-year-old red plum apricot garden planted 2018 .
Generally, some 2- year-old red plum apricot trees start to bear fruit. 3 -year-old red plum apricot forest has some yield and the yield of 4 -year-old red plum apricot forest have reached a certain level after planting red plum apricot tree. An adult red plum apricot tree start to bloom in the end of March and are in full bloom in the first ten-day period of April, red plum apricot fruit is in the expansion period of fruit from the second ten-day period of May to the second ten-day period of June, and fruit mature in the first ten-day period of July, and leaf drop in the middle and last ten-day period of September. Once serious drying happens in the Fruit expansion stage, leaf of red plum apricot tree change colour from green to yellow or croci, and drop earlier. The size of red plum apricot fruit is smaller than normal fruit, which influence the yield, quality and economic benefits of red plum apricot.