EFFECTS OF FOLIAR NUTRIENT AND BIOSTIMULANT APPLICATIONS AND SOIL MOISTURE AND NUTRIENT STATUS ON ESTABLISHMENT OF NEWLY-LAID SOD OF ZOYSIA SP

摘要

Zoysiagrasses (Z.japonica Steud.,Z.matrella (L.) Merr.and Z.pacifica (Goudswaard) M.Hotta & S.Kuroki,plus some interspecific hybrids) have many positive attributes as low maintenance,slow-growing warm-season turfgrasses once established,producing high quality turf with low nutrient inputs and requiring less frequent mowing than alternative turfgrass species.During establishment,however,their slow growth is seen as their major weakness.Five short-term pot experiments to simulate the laying of vegetative zoysiagrass (Z.matrella,Z.japonica) sod onto a bare soil base were conducted in glasshouses in Brisbane,Australia (27°30’S,153°01’E),maintaining moisture in the turf sod and growing medium via capillary watering from below.This avoided the need for heavy overhead watering,thus enabling the effects of foliar nutrient and biostimulant treatments to be considered without being complicated by leaching into the sod and underlay medium.The artificial sand-peatmoss (or coir) growing media were strongly acid (pH 4.5-5.3) and low to very low in terms of sufficiency levels of N,P and K,and most other major and minor nutrients.Despite this,root development under newly-laid zoysiagrass sod and the partitioning of dry matter production into root rather than shoot growth were enhanced by maintaining low soil fertility and not applying fertiliser at establishment None of the foliar nutrient (high N,P or K) or biostimulant treatments (kelp or microbial supplementation) made during the first 21 days resulted in a positive response in terms of root development in the first 6 weeks of establishment.Growth increased with temperatures,leading to higher dry matter production but with reduced partitioning of this into roots.Drying out of zoysiagrass sod prior to laying did not disproportionately affect subsequent root development,and had relatively little effect on final establishment for the first 2 days of drying out.However,it also appears that the maintenance of good sod and soil moisture is of paramount importance during early establishment to protect delicate new root growth once this has been initiated.