Abstract: [Objective]Agricultural and forestry residues have many advantages, e.g. accessible, containing a certain amount of nutrients. It is meaningful to reuse them as a matrix of container seedlings to replace non-renewable peat. Our objective is to explore an excellent matrix for the seedlings, by comparing the water and nutrient preservation of nursery matrix composed of agri-forest residues.[Method]These media were composed of waste sticks after edible fungus culture, corn cores or corn straws, with adding larch needle-humus and vermiculite. And then either 1% or 0.5% water retention agent were added to some of the nursery media.[Result]1) The pH, bulk density and total porosity reached the ideal culture substrate requirements in the three agri-forest residues matrices. These indexes had no significant difference from those of peat-soil matrix. 2) Without water retention agent, the water retaining ability of waste fungus matrix and the corn maturity core matrix was almost the same as that of peat-soil matrix. All kinds of matrices with adding 1% water retention agent had significant higher water retaining ability than those with adding 0.5% water retention agent. The water retaining abilities of waste fungus matrix and of corn maturity core with 1% water retention agent adding were all significant higher than that of peat-soil matrix(P<0.05). 3) After adding water retention agent, the overall nitrogen, phosphorus and potassium loss was significantly less than those without water retention agent addition. The more the water retention agent was added, the less nutrient elements lost, reducing by 20%-40%. When added 1% water retention agent, nutrient preserving ability of all kinds of matrices was significantly higher than that of peat-soil matrix(P<0.05), just missing 50%-77% nutrient of peat-soil matrix. 4) Without water retention agent, the seedling height and stem diameter had no significant difference among all the treatments and control. But the ratio of height to stem diameter was significant higher than those in the peat-soil matrix. The seedling quality index was higher in matrix with 1% water retention agent than that in 0.5%, especially the matrix with corn core.[Conclusion]The water and nutrient preservation of nursery matrix composed of agri-forest residues was similar to peat-soil matrix. It is suggested that 1% water retention agent should be added into the agri-forest residues matrices to promote the growth of seedlings.

Key words: agricultural and forestry residues, water-retaining property, nutrient preserving ability