Irrigation modes screening for water saving, high yield and quality of dwarfed and densely planted fragrant pears in South Xinjiang of China

An extensive field study was presented to optimize the irrigation techniques for water use efficiency (WUE) and yield in dwarf and densely planted fragrant pears in South Xinjiang. A two-factor and fully randomized design was conducted in the 29th regiment of Xinjiang. Three advanced micro-irrigation systems were selected—surface drip irrigation (M1), subsurface drip irrigation (M2), and root-zone infiltration irrigation (M3)—with traditional flood irrigation (CK) as a comparative baseline. Three irrigation quotas were set as low (I1), medium (I2), and high (I3) to evaluate their suitability under the varying limitations of water resources. A systematic analysis was then implemented to assess the impact of these irrigation modes on several critical parameters, including electrical conductivity (EC), desalination rate, growth patterns, yield, WUE, fruit quality, and economic viability. The results show that the subsurface drip irrigation (M2) demonstrated superior performance to enhance the yield and WUE. Notable benefits were obtained to promote the pear growth for the fruit quality. The performance was statistically comparable to M3 (P > 0.05) in the effective salt leaching. Moreover, irrigation modes and irrigation quotas significantly dominated the soil salinity distribution (P<0.05). Three micro-irrigation modes produced a certain degree of salt aggregation, except for the diffuse irrigation. The difference among irigation modes was not significant (P>0.05). Both irrigation modes and irrigation quotas dominated the yield and water use efficiency of fragrant pear. The fruit diameter, yield, water use efficiency, and net profit of M1 were significantly higher than those of surface irrigation (CK and M1) under the same irrigation quotas. But there was no significant difference with M3 (P<0.05). Despite the higher initial investment, M3 generated substantial net profits, second only to M2. Further analysis revealed that the higher irrigation quota consistently improved the fragrant pear growth, yield, and salt-leaching efficiency. PPrincipal Component Analysis (PCA), technique for order preference by similarity to an ideal solution (TOPISIS), and rank-sum ratio (RSR) were also employed to evaluate—integrating environmental, qualitative, and economic factors, and then identify fifteen key indices. The M2I3 treatment emerged as the most effective, while M1I1 was the least. In conclusion, the M2 irrigation mode was recommended for the dwarf and densely planted first-fruiting fragrant pears. An optimal irrigation quota of 6 750 m³/hm² was achieved in the growth period. This finding can greatly contribute the significant insights and practical guidance for the higher efficient, water-conserving, and salt-controlled production in the arid regions of Southern Xinjiang. Substantial theoretical and technical support can also be offered for the forestry and fruit industry. Furthermore, a scientific basis can be gained for the application of water-saving irrigation in the "labor-saving and dense planting" cultivation area of fragrant pear.