Drip irrigation with film covering improves soil enzymes and muskmelon growth in the greenhouse

The present study evaluated responses of soil enzyme activity, soil micro-organisms, muskmelon root growth and muskmelon fruit yield and quality to different levels of film covering (full, half and no plastic film covering), drip pipe density (one pipe for one row (T-1), three pipes for four rows (T-3/4) and one pipe for two rows (T-1/2)) and different lower limits of irrigation (60%, 70% and 80% of field capacity) in a greenhouse experiment using an orthogonal experimental design. Half film mulch cover resulted in higher muskmelon root activity (second only to full film covering) during the fruit swelling growth stage and promoted soil micro-organism growth. Compared with full and no film cover conditions, under half film cover mean soil urease activity was 25.16% and 1.46% higher, alkaline phosphatase (ALP) activity was 18.42% and 16.89% higher and catalase activity was 24.20% and 17.24% higher respectively. Compared with T-1 and T-3/4, under T-1/2 mean soil ALP activity was 22.36% and 5.76% higher, catalase activity was 2.45% and 10.57% higher and muskmelon root activity during the fruit swelling period was 1.13- and 3.98-fold higher respectively. Irrigation at both 60% and 80% of field capacity improved muskmelon root length and area, soil micro-organism populations and soil urease, ALP and catalase activity. In addition, half film covering, irrigation at 80% field capacity and T-1/2 improved the partial factor productivity for nitrogen, yield and fruit quality of muskmelons in the greenhouse. Therefore, these conditions appear to be the most appropriate agronomic configuration for muskmelon cultivation in greenhouses.