Effects of different treatments of water and fertilization on growth and fruiting of Chinese jujube

Abstract: 【Objective】Chinese jujube has been cultivated in China for a long time. Rasonable water and fertilizer management is important for efficient cultivation and quality fruit production of the jujuba. The objective of this study was to explore the suitable water and fertilization management for the growth and fruiting of Chinese jujube and provide reference for water and fertilizer management of fresh cultivars Yueguang and Dongzao in the Taihang Mountain area of Hebei province.【Methods】 This experiment was conducted at the Fuping Comprehensive Experimental Station of Chinese Jujube Industry, Hebei Agricultural University in Fuping County, Baoding City, Hebei Province from 2021 to 2022. 5-year old Yueguang and Dongzao trees were used as the materials. Their branch and leaf growth (number of newly emerged jujube shoots, extension shoot length, extension shoot diameter, secondary shoot internode length, secondary shoot length of extension shoot, bearing shoot length, number of leaves per bearing shoot, content of N, P, K, Ca, Mg elements), flowering (number of inflorescence per bearing shoot and flowers per bearing shoot), and fruit quality (single fruit weight, longitudinal diameter, transverse diameter, fruit shape index, vitamin C content, titratable acid content, soluble sugar content, soluble solid content, sugar acid ratio) were investigated under four conditions, including low water and fertilizer treatments (10 t of drip irrigation water, 15 kg of water-soluble fertilizer A and 15 kg ofwater-soluble fertilizer B per 666.7 m2 per year), medium water and fertilizer treatments (12 t of drip irrigation water, 20 kg of water-soluble fertilizer A and 25 kg of water-soluble fertilizer B per 666.7 m2 per year), high water and fertilizer treatments (14 t of drip irrigation water, 25 kg of water-soluble fertilizer A and 40 kg of water-soluble fertilizer B per 666.7 m2 per year) and the control (no application of water and fertilizer, CK).【Results】The results showed that the different water and fertilization treatments had no significant effects on the length of bearing shoots in both Yueguang and Dongzao varieties. The number of newly emerged jujube shoots, extension shoot length, secondary shoot internode length, secondary shoot length of extension shoot, the number of inflorescence per bearing shoot and the number of flowers per bearing shoot were significantly higher in Yueguang with the high water and fertilizer treatments than those with the low water and fertilizer treatments and the CK. The number of newly emerged jujube shoots, the number of inflorescence per bearing shoot and the number of flowers per bearing shoot were significantly higher in Dongzao with the medium water fertilizer treatments than those the high water fertilizer treatments and the CK. Yueguang with the high and medium water fertilizer treatments had significantly higher single fruit weights in 2021 than that with the low water fertilizer treatments and the CK. The single fruit weights increased sequentially with increasing amounts of water and fertilizer in 2022, the single fruit weight with the high water fertilizer treatments was the largest although there were no significant differences between the treatments. Under the conditions of medium and high water and fertilization treatments, the nutrient content of Yueguang fruits was generally higher. The single fruit weight of Dongzao increased with different water and fertilizer treatments compared with the CK, by 16.61%, 4.07% and 27.76% from low to high water and fertilizer treatments respectively. As the amount of water and fertilizer increased, the titratable acid content and of Dongzao decreased, while the sugar-acid ratio increased and the fruits became sweeter. The fruit quality of Dongzao was the best under the medium water and fertilization treatments. After the water and fertilizer treatments, the contents of N, P, K, Mg elements of the two varieties were higher than those of the control, and the contents of N, P, K, Mg elements increased with the increase in the amount of water and fertilizer, and the peak appeared after the medium water fertilizer treatments, and then decreased. While Ca elements decreased with the increase of the amount of water and fertilizer.【Conclusion】The medium water and fertilizer management for Dongzao and the high water and fertilizer management for Yueguang should be recommended for proper growth and quality fruit production in the Mountain Taihang area of Hebei province.