The Combined Effect of Irrigation and Fertilization on Yield and Quality of Fruits of Chinese Date

Abstract

【Objective】 Jujube (Chinese date) is an important cash crop in southern Xinjiang but its production relies on irrigation and fertilization due to the limited rainfall in this region. This paper aims to investigate the combined effect of irrigation and fertilization on yield and quality of jujube fruits in attempts to find an optimal irrigation-fertilization combination for jujube production in this region. 【Method】 The field experiment was conducted in a 10-year-old orchard in the 224 Regiment of Kunyu City; it is a typical self-pressurized irrigation area in southern Xinjiang. The experiment had three irrigation treatments: irrigating 540 mm (W1), 630 mm (W2) and 720 mm (W2) of water. Each treatment had three fertilizations: 562.5 kg/hm2 (F1), 810 kg/hm2 (F2) and 1 080 kg/hm2 (F3). The control was fertigation used by local growers: irrigating 770 mm of water and applying 1 125 kg/hm2 of nitrogen fertilizer (CK). In each treatment, we measured fruit yield and quality. 【Result】 Irrigation amount affected irrigation water use efficiency (IWUE), single-fruit weight, transverse and longitudinal diameters and quality of the fruits, all at significant levels (P<0.05). Fertilization impacted fruit quality significantly with P<0.05, fertilizer partial productivity (PFP), single fruit weight, transverse and longitudinal diameters of the fruits significantly with P<0.01. The combined effect of irrigation and fertilization on yield, IWUE, PFP, and fruit quality was significant with P<0.01. The highest yield and IWUE appeared in W2+F3, which differed significantly from those in CK (P<0.05). W2+F2 gave the best fruit quality-measured in single fruit weight, transverse and longitudinal diameters of the fruits. W2+F2 and W2+F3 did not show significant difference in fruit quality, except for the numbers of top-graded fruits. 【Conclusion】 An optimal combination of irrigation and fertilization can improve yield, appearance quality and grade ratio of the jujube fruits. Comprehensive analysis considering both fruit quality and water and fertilizer use efficiency indicated that the optimal irrigation and fertilization for the jujube was to irrigate 639.21~642.85 mm of water, and fertilize 374.38~384.02 kg/hm2 of N, 87.19~192.01 kg/hm2 of P2O5, and 280.79~288.02 kg/hm2 of K2O.

Keywords

• junzao
• drip irrigation
• water and fertilizer ratio
• yield
• fruit grade
• junzao grade ratio