A long-term experiment to study the role of mulches in the physiology and macro-nutrition of strawberry grown under water stress
Strawberry (Fragaria × ananassa Duch) cv. 'Oso Grande' was grown in the field from July 1999 to May 2000 in order to investigate the effectiveness of different mulch types on fruit yield, quality (i.e. soluble dry matter, fruit size), leaf nutrient compositions, and normal plant growth parameters in strawberry grown under water stress. Treatments were: (1) bare soil + water stressed (WS), (2) bare soil + unstressed (control), (3) black polyethylene mulch + water stressed (BPM + WS), (4) wheat straw mulch + water stressed (WSM + WS), (5) wheat straw mulch plus black polyethylene mulch + water stressed (WSM + BPM + WS). Water stress was created by irrigating plants once every 3 days at 50% A pan (Epan) evaporation, compared with the control, which received 75% daily. WS caused reductions in all parameters, except water-soluble dry matter concentrations in fruits, compared with the control treatment. Both BPM and WSM improved the fruit yield, fruit size, plant dry matter, leaf area index, and chlorophyll concentrations in leaves in the stressed treatments, while these 2 mulches in combination (BPM + WSM) caused further increases in these parameters. WS enhanced electrolyte leakage by impairing membrane permeability compared with control treatment. Mulching, especially BPM and WSM together, substantially decreased electrolyte leakage. WS reduced leaf concentrations of all nutrients tested (N, P, K, Ca, and Mg). However, mulching, especially BPM and WSM together, enhanced the concentrations of these nutrients, but their concentrations were still lower than those in the control treatment. These results clearly indicate that mulching mitigates negative effects of water stress on plant growth and fruit yield in field-grown strawberry, particularly in semi-arid situations.