Shelf Life and Tensile Strength of Turfgrass Sod Amended with Recycled Biosolid.

The objective was to compare post-harvest traits among sods grown with and without recycled composted biosolids (CB) at fertilizer N rates of 0, 150, and 300 kg/ha. The CB (0.6-cm depth) was topdressed on regrowth of Tifway bermudagrass and the three fertilizer N rates were randomly assigned to treatments with and without CB. For shelf-life evaluations, sod blocks (45 x 45 cm) were harvested to a 2.2-cm depth from treatments grown with and without each CB and fertilizer N. Temperature was measured and recorded continuously for 72 hr within stacks of 7 sod blocks that were enclosed within insulated boxes. Greater soil total N and organic C of sod with than without CB and greater turfgrass dry weight at high compared to low N contributed to only slightly greater temperatures than sod with no CB and fertilizer N over 72 hr. At 7 d after incubation for 36 or 72 hr, visual ratings indicated turf quality of transplanted sod blocks was slightly lower for sod removed at 72 hr. Quality ratings 7 and 21 d after incubation were greater for sod produced with 300 kg fertilizer N/ha than without fertilizer N. For sod tensile strength measurements, blocks were clamped at opposite edges and a load cell measured the peak force required to tear sod during retraction of a hydraulic cylinder. Although gravimetric water content was 39% greater for sod grown with than without CB, the mean peak force required to tear sod was similar (205 Newtons) with or without CB. In addition, mean sod strength was comparable among sods grown at the three fertilizer N rates. Although CB amendments increased total N and organic C and water content in sod harvested from mature turf, effects on sod heating within stacks of blocks and sod tensile strength were minimal.