Effects of Compost Sources and Seeding Treatments on Germination and Emergence of Four Turfgrass Species

Abstract

Greenhouse pot trials were conducted to compare the effects of compost sources and planting treatments on turfgrass germination and emergence. Eight seeding treatments and 4 turfgrass types were factorially combined and replicated four times in a completely randomized block design. The seeding treatments were: 1) seed planted on surface of 2.6 cm compost overlying soil, 2) seed planted on soil surface below 0.65 cm compost, 3) seed planted on soil surface below 1.3 cm compost, 4) seed planted on soil surface below 2.6 cm compost, 5) seed planted on soil surface covered with a 2.6 cm straw mat, 6) seed planted below 1.3 cm soil, 7) seed planted below 1.3 cm of 1:1 compost:soil mix, and 8) seed planted on soil surface. Tall fescue (Festuca arundinacea Schreb.), Kentucky bluegrass (Poa pratensis L.), bermudagrass (Cynodon dactylon L.), and zoysiagrass (Zoysia japonica Steud.) were used as the bioassay crops. The experimental design was repeated over time using composts produced with the following feedstocks: yard waste, food waste, dairy manure, biosolids, and paper mill sludge. Emerged seedlings were counted at 11 days for tall fescue, at 3 weeks for Kentucky bluegrass and at 7 weeks for bermudagrass and zoysiagrass. There were significant (P<0.05) effects of seeding treatment x turfgrass type on germination and emergence for each compost type. All of the composts appeared to be well stabilized using routine compost laboratory testing except the biosolids compost, whose use resulted in the lowest overall germination and emergence rate. The highest rates of germination and emergence occurred in the treatments in which the seeds were planted on the surface, regardless of whether the surface was compost or soil. The lowest rate of germination and emergence occurred where the seed was placed under 2.6 cm compost, regardless of compost maturity.