AN EFFICIENT METHOD FOR MEASURING SOD RESERVES FOR GREENHOUSE AND FIELD STUDIES

Nonstructural carbohydrates and other reserves in roots, rhizomes, sto lons, crowns, or stubble determine regrowth by grass sod after defolia tion. Traditionally, these reserves have been estimated by collecting and growing 15-cm sod plugs with optimum water and temperature in a da rkroom and measuring etiolated mass per unit area. An improved samplin g tool and mini-darkrooms made by taping an inverted no. 10 (15-cm dia m.) can over a similar can containing a sod plug at or near field capa city are described. A slight depression in the top of the can allows f or air exchange but minimizes water loss. Dry matter reserves of 1.18 g for 'Coastal', 2.26 g for 'Tifton 78', and 3.62 g for 'Tifton 44' be rmudagrass [Cynodon dactylon (L.) Pers.], were measured with approxima tely one-fourth less time needed to harvest, water, and retape the cov ers than for traditional methods.