Does water-saving irrigation improve the quality of fruits and vegetables? Evidence from meta-analysis

Water productivity has become a key requirement in sustainable crop production and environmental management. Deficit irrigation (DI) and partial root-zone drying irrigation (PRDI) are two strategies that have been exploited to maximize crop production per unit water, with attendant effect on the quality attributes of harvest index. We employed meta-analysis to synthesize evidence for the relative performance of full irrigation (FI), DI and PRDI for three quality attributes of fruits and vegetables, namely, total soluble solids (TSS), titratable acidity (TA) and pH. Overall, TSS, TA and pH of crops under DI and PRDI do not differ significantly. However, TSS in crops under DI and PRDI are significantly larger than that of crops under FI. DI and PRDI improve TSS by 4.1 +/- 1.8% and 5.0 +/- 2.0%, respectively, relative to FI. Crops under the three irrigation techniques do not differ significantly in TA and pH. The differences in TSS of crops are contextual, depending on type of crop, soil texture and irrigation frequency. The effect of water-saving irrigation on the selected crop quality attributes may, therefore, have the add-on effects of crop, system and/or site characteristics. Therefore, in terms of quality attributes, water-saving irrigation techniques are superior to FI when considering improvement in TSS without significantly altering TA or pH of fruits and vegetables.