Coupling effect of water and fertilizer on potted Euphorbia pulcherrima in greenhouse.

In order to reduce the production cost and improve the utilization efficiency of water and fertilizer, and to realize the precise control of potted flowers, we studied the effect of different watering frequencies and fertilizer amounts on the plant height, crown diameter, biomass, blooming duration and number of flowers of Euphorbia pulcherrima by pot culture and quadratic general rotary design. The results indicated that watering frequency and fertilizer amount markedly affected the plant height, crown diameter, biomass and blooming duration of E. pulcherrima, and fertilizer amount had more obvious impacts than watering frequency. The regression models were both accurate and reliable, and could be used for prediction of production. The optimum matching control methods of water and fertilizer were found for E. pulcherrima in a growth medium V(corn stalk)∶V(sawdust)∶V(perlite)=2∶1∶1 by equation fitting and simulating optimization. The optimum watering frequency was: once the water content of the medium ranged from 59.28%-66.83%, watering 50000 mL per pot; the optimum fertilizer amount was 756.02-833.33 mg per pot, once a week.