This experiment examined the effects of blending bottom ash produced after combusting dry livestock manure (BACL, 2-4 mm particle) as a soil amendment on the physicochemical properties of the root zone and growth response of creeping bentgrass in sandy soil. The treatments were designed as follows: control [100% sand], 3% BACL (3% BACL + 97% sand), 5% BACL (5% BACL + 95% sand), 7% BACL (7% BACL + 93% sand), and 10% BACL (10% BACL + 90% sand). Although BACL improved the soil physical properties, such as the capillary porosity, total porosity, and hydraulic conductivity, it reduced the cation exchangeable capacity. The BACL treatments increased the pH, EC, Av-P2O5, and Ex-K compared to the control. The turf color index, chlorophyll content, shoot length, clipping yield, and shoot dry weight after the BACL treatments were similar to the control. The growth and nutrient uptake of the roots in the BACL treatment were higher than those of the control. The BACL application amount was positively correlated with the capillary porosity and total porosity of the root zone (p <= 0.01) and with the growth and nutrient levels of the roots (p <= 0.05). These results suggest that applying BACL as a soil amendment enhanced the uptake of phosphorus and potassium in the roots of creeping bentgrass by improving the soil porosity in the root zone and by supplying phosphate and potassium.
Root-knot nematodes were discovered in severely declining creeping bentgrass putting greens at a golf course in Indian Wells, Riverside County, California. The exhibited disease symptoms included chlorosis, stunted growth, and dieback. Based on morphological examination and measurements of J2 females and males, it was suggested that the causal pathogen was Meloidogyne marylandi. This identification was confirmed by analysis of the D2-D3 expansion segments of 28S rRNA and COI gene sequences. The host status of 28 plant species was evaluated in greenhouse trials. All tested monocots, except rye and Allium species, were found to be hosts, while no reproduction occurred on dicots. Temperature-tank experiments helped determine that the life cycle of M. marylandi was completed between 17-35 degrees C, with a base temperature of 8.3 degrees C and a required heat sum of 493 degree-days (DD). In greenhouse trials in pasteurized soil and near-ideal growing conditions, M. marylandi did not cause significant growth reduction of creeping bentgrass cv. Penn A-4, even at very high J2 inoculation densities. It is highly probable that other biotic and abiotic factors contributed to the observed putting green damage.