Effect of drip irrigation pattern on wine grape growth, yield, photosynthesis and water use efficiency in arid desert regions

A field experiment was conducted in Hexi Corridor arid desert region, Gansu Province, to study the effects of drip irrigation amount on wine grape growth, photosynthesis, water use efficiency, yield and fruit quality under plastic-film and no mulching. The study revealed significant enhancement of primary and secondary new shoot length and main grape vine diameter with increasing drip irrigation amount. Even under low drip irrigation, better grape growth with higher above-3 index was noted in plastic-film mulching than in no plastic-film mulching. Under different drip irrigation amounts with or without plastic-film mulching, the rates of daily net photosynthetic rate, transpiration rate and stomatal conductance tracked a similar trend of continuous decline. However, the rate of intercellular CO₂ concentration initially declined and then increased. The photosynthesis indices of plastic-film mulching with 240 mm (T1) and 300 mm (T2) irrigation treatments were not only lower than those with 360 mm (T3) and 420 mm (T4) irrigation treatments, but also that of no mulching with 360 mm (CK) irrigation treatment. T1 water use efficiency was the highest among the treatments. Based on regression analysis, the correlation between intercellular CO₂ concentration and soil moisture was the most significant. This was followed by that between intercellular CO₂ concentration and stomatal conductance, then net photosynthesis rate and then transpiration rate. Grape yield of treatments with plastic-film mulching were higher than no-mulching treatment. Sugar content of grape fruits was highest under no-mulching treatment, followed by T1 treatment. T1 was the optimal treatment for high grape quality and yield production, with the most efficient water resource use.