Drip irrigation with film mulch improves soil alkaline phosphatase and phosphorus uptake

Phosphorus (P) is essential for various metabolic activities in plants and plays an extremely important role in crop development, yield and quality. Organic P fertilizers can provide sustainable P and maintain agroecosystem health; however, the uptake of soil organic P by plants is significantly influenced by soil phosphatase activities. The objective of this study was to quantify the effects of different layout measures (film covering, drip irrigation line density, and irrigation lower limits) in drip irrigation with film mulch on the soil phosphatase activity, culturable microorganism populations and crop growth and yield in a greenhouse. The results show that the greatest levels of soil alkaline phosphatase activity were observed with an irrigation lower limit of 80%, a field capacity of 50%, and film mulch covering but were relatively insensitive to the drip irrigation line density. Soil alkaline phosphatase activity was also significantly correlated with the root growth and culturable microbial populations. Specifically, soil alkaline phosphatase activity was positively correlated with the actinomycete population and root activity but negatively correlated with root volume and root area. These results can be used to improve crop production in greenhouse conditions in China.