Evaluation of Spent Coffee and Tea As Topdressing Materials.

Many sandy soils lack the nutrient and water retention that are necessary for turf growth. Once turf is established, the addition of high volume organic soil amendments  is limited to surface applications. A study was designed to determine the soil chmical and physical effects of topdressed organic materials on Tifway bermudagrass growing in a USGA spec root zone (90:10 sand:reed-sedge peat) maintained at 1.3 cm. Treatments consisted of reed-sedge peat (RS), sphagnum peat (SP), non-composted spent coffee grounds (C), non-composted spent tea leaves (T), sand (S), 50:50 mixes (v:v) of sand with each of the organic treatments, and an untreated control. Treatments were applied every two weeks by hand during August and September at a depth of 3.2 mm per application and were brushed into the turf canopy. Organic treatments had a beneficial effect on color beginning in mid-August and continuing through dormancy. Organic treatments alone improved water holding capacity compared to the control, while sand+organic treatments did not have an effect. Surface hardness measurements consistently showed that C treatments were softest and control plots hardest. A chemical soil analysis conducted at the end of the growing season determined all organic treatments produced a slight improvement in CEC, but had no effect on percent organic matter. Levels of K and P were most increased by C and least by RS. Sand+SP and SP were the only treatments to reduce pH compared to the control. Electrical conductivity measurements showed that C, T, and RS all had higher values than control in the topdressing layer. Other soil depths (thatch layer and sand layer) did not show differences among treatments.