Turfgrass Soil Research Articles

Nutrient Accumulation and Availability in Compost-amended Turfgrass Soil

Compost application to turfgrasses may contribute to accumulation of macronutrients in soil and eventually pose leaching and runoff hazards. The objectives of this study were to determine the influence of compost on soil-dissolved organic C (DOC) and accumulation of NH4OAc-EDTA-extractable and water-soluble nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S) in St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] turf. Dissolved organic C increased from 3 to 29 months after application for unamended and compost-amended soils, indicating contribution from decomposition of both compost and St. Augustinegrass residues. Dissolved organic C was 75%, 78%, and 101% greater 29 months after application of 0, 80, and 160 mg·ha−1 of compost, respectively, than before application. Dissolved organic C and macronutrients exhibited considerable seasonal variation, because DOC and EDTA-extractable P, Ca, Mg, and S increased after compost application, whereas NO3 declined. Water-soluble K, Ca, and Mg declined, whereas P and S increased from 0 to 29 months. Similar seasonal changes in macronutrient concentrations occurred for unamended and compost-amended soil, indicating that composts, in addition to turfgrass residues, influenced DOC and macronutrient dynamics. Long-term nutrient accumulation occurred in compost-amended turfgrass, but seasonal dynamics were more related to the growth stage of turfgrass than compost. Formation of DOC-cation complexes appeared to contribute to macronutrient mobility, because decreases in DOC and nutrient concentrations occurred during turfgrass dormancy in winter and after high precipitation levels, indicating the potential for leaching of DOC-associated nutrients from soil.

Compost impacts on dissolved organic carbon and available nitrogen and phosphorus in turfgrass soil

Compost application to turfgrass soils may increase dissolved organic C (DOC) levels which affects nutrient dynamics in soil. The objectives of this study were to investigate the influence of compost source and application rate on soil organic C (SOC), DOC, NO(3), and available P during 29 months after a one-time application to St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] turf. Compost sources had variable composition, yet resulted in few differences in SOC, DOC, and NO(3) after applied to soil. Available NO(3) rapidly decreased after compost application and was unaffected by compost source and application rate. Available P increased after compost application and exhibited cyclical seasonal patterns related to DOC. Compost application decreased soil pH relative to unamended soil, but pH increased during the course of the study due to irrigation with sodic water. Increasing the compost application rate increased SOC by 3 months, and levels remained fairly stable to 29 months. In contrast, DOC continued to increase from 3 to 29 months after application, suggesting that compost mineralization and growth of St. Augustinegrass contributed to seasonal dynamics. Dissolved organic C was 75%, 78%, and 101% greater 29 months after application of 0, 80, and 160 Mg compostha(-1), respectively, than before application. Impacts of composts on soil properties indicated that most significant effects occurred within a few months of application. Seasonal variability of SOC, DOC, and available P was likely related to St. Augustinegrass growth stages as well as precipitation, as declines occurred after precipitation events.

Species diversity and seasonal abundance of Collembola in turfgrass ecosystems of North America

Summary In North America, lawns are the most widely used plantings in urban areas. However, despite the ubiquity and ecological roles of turfgrass soil arthropods, many aspects of their composition and diversity have been neglected. We investigated assemblages of Collembola and their seasonal fluctuations in a newly established lawn and a 10-year old lawn located in Quebec City, Canada. Collembola were sampled every month from May to October in 2003 and 2004 by extracting individuals from soil cores using a modified Berlese funnel. A total of 21 species representing 17 genera and nine families were identified. Four species are new records for the province of Quebec: Brachystomella parvula , Mesaphorura simplex , Isotomodes productus , and Sphaeridia pumilis . Turfgrass supports mainly three cosmopolitan species from the Isotomidae family, which represent 73.5% of all Collembola collected during the survey: Parisotoma notabilis , Isotoma viridis , and Cryptopygus thermophilus . Collembola were twice more abundant at the newly established site, but there were minor differences in species diversity between sites and years. No clear patterns of seasonal relative abundance were observed for the whole Collembola populations, as well as for the three dominant species. Turfgrass ecosystem provides a suitable habitat for epedaphic and hemiedaphic Collembola, such as the Isotomidae, most likely because turfgrass mowing and natural leaf, stem and root replacement produces large amounts of decaying organic matter.

Degradation of N‐Nitrosodimethylamine (NDMA) in Landscape Soils

N-nitrosodimethylamine (NDMA), a potential carcinogen, was commonly found in treated wastewater as a by-product of chlorination. As treated water is increasingly used for landscape irrigation, there is an imperative need to understand the leaching risk for NDMA in landscape soils. In this study, adsorption and incubation experiments were conducted using landscape soils planted with turfgrass, ground cover, and trees. Adsorption of NDMA was negligibly weak (K(d) < 1) in all soils, indicating that NDMA has a high potential for moving with percolating water in these soils. Degradation of NDMA occurred at different rates among these soils. At 21 degrees C, the half-life (t(1/2)) of NDMA was 4.1 d for the ground cover soil, 5.6 d for the turfgrass soil, and 22.5 d for the tree soil. The persistence was substantially prolonged after autoclaving or when incubated at 10 degrees C. The rate of degradation was not significantly affected by the initial NDMA concentration or addition of organic and inorganic nutrient sources. The relative persistence was inversely correlated with soil organic matter content, soil microbial biomass, and soil dehydrogenase activity, suggesting the importance of microorganisms in NDMA degradation in these soils. These results suggest that the behavior of NDMA depends closely on the vegetation cover in a landscape system, and prolonged persistence and increased leaching may be expected in soils with sparse vegetation due to low organic matter content and limited microbial activity.

Mobility and dissipation of ethofumesate and halofenozide in turfgrass and bare soil.

The effect of turfgrass cover on the leaching and dissipation of ethofumesate and halofenozide was studied. Sampling cylinders (20 cm diam. x 30 cm long) were placed vertically in plots of creeping bentgrass (Agrostis palustris Huds.), tall fescue (Festuca arundinaceae Schreb.), or bare soil. ethofumesate [(+/-)-2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methansulfonate] was applied at 840 g ai ha(-)(1) on September 21, 1997. Halofenozide (N-4-chlorobenzoyl-N'-benzoyl-N'-tert-butylhydrazine) was applied at 1680 g ai ha(-)(1) on August 30, 1998. Replicate sampling cylinders were removed 2 h after treatment and 4, 8, 16, 32, and 64 days after treatment. Sampling cylinders were sectioned by depths and soil extracts were assayed by HPLC with a pesticide detection limit of 0.01 mg kg(-)(1). Turfgrass was divided into verdure and thatch and analyzed separately. ethofumesate leaching in turfgrass was reduced by at least 95% compared to leaching in bare soil. The half-life of ethofumesate in bare soil was 51 days compared to 3 days in turfgrass. Halofenozide showed similar leaching with or without turfgrass. Fifty percent dissipation of halofenozide did not occur within 64 days, regardless of organic matter cover.

Identification and Impact of Egg Predators ofCyclocephala luridaandPopillia japonica(Coleoptera: Scarabaeidae) in Turfgrass

Field experiments were conducted to identify predators of southern masked chafer, Cyclocephala lurida Bland, and Japanese beetle, Popillia japonica Newman, eggs in turfgrass soil and to measure the predation that occurs. Identification of egg predators was determined by direct observation through buried Plexiglas plates of artificially placed eggs. Predation rates of Japanese beetle eggs was further measured using buried bait stations filled with eggs. Up to 73% of eggs in the soil were taken within a 72-h period. Ants were found to be the predominant predator accounting for up to 83% of the eggs taken. One species of ant, Solenopsis molesta (Say), proved to be the primary ant predator of eggs in turfgrass.

In vitro pesticide degradation in turfgrass soil incubated under open and sealed conditions.

Degradation of selected pesticides was conducted in a turfgrass soil from a golf course under open (i.e., allowing gas exchange with atmosphere) and sealed systems. The time required for 50% of the initial dose of fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate), diazinon (O,O-dimethyl O-2-isopropyl-6-methylpyrimidin4-yl phosphorothioate), iprodione [3-(3,5-dichlorophenyl)-N-isopropyl-2,4-dioxo-imidazolidine-1-carboxamide], mecoprop [(RS)-2-(4-chloro-otolyloxy)propionic acid], and asulam (4-aminophenylsulfonyl-carbamate) to dissipate (half-life, t 1/2) was less than 2 wk under both conditions. The t 1/2 values of dithiopyr (S,S'-dimethyl 2-difluoromethyl-4-isobutyl-6-trifluoro-methylpyridine-3,5-dicarbothioate) were 324 and 185 d under the open and sealed conditions, respectively. The t 1/2 values of isoprothiolane (di-isopropyl 1,3-dithiolan-2-ylidene-malonate), flutolanil (alpha,alpha,alpha-trifluoro-3'-isopropoxy-o-toluanilide), and benefin (N-butyl-N-ethyl-alpha,alpha,alpha-trifluoro-2,6-dinitro-p-toluidine) under the open conditions were 154, 336, and 47 d, respectively. The t 1/2 values of these pesticides increased slightly under the sealed conditions. The t 1/2 values of terbutol (2,6-di-tert-butyl-4-methylphenyl N-methycarbamate) and one of the major degradation products, N-demethyl-terbutol (2,6-di-tert-butyl-4-methylphenyl carbamate), were 182 and 291 d under the open conditions and increased by six- and threefold under the sealed conditions, respectively. The degradation system under the sealed conditions could characterize the persistence of terbutol and N-demethyl-terbutol, which were the most persistent in the field.

The role of tree leaf mulch and nitrogen fertilizer on turfgrass soil quality

The influence of tree leaf amendment and N fertilization on soil quality in turfgrass environments was evaluated. Our objective was to assess changes in soil quality after additions of leaf materials and N fertilization by monitoring soil chemical and physical parameters, microbial biomass and soil enzymes. Established perennial ryegrass (Lolium perenne) plots were amended annually with maple (Acer spp.) leaves at three different rates (0, 2240, and 4480 kg ha–1 year–1) and treated with three nitrogen rates (0, 63, and 126 kg N ha–1 year–1). Tree leaf mulching did not significantly affect water infiltration or bulk density. However, trends in the data suggest increased infiltration with increasing leaf application rate. Tree leaf mulching increased total soil C and N at 0–1.3 cm depth but not at 1.3–9.0 cm. Extracted microbial phospholipid, an indicator of microbial biomass size, ranged from 28 to 68 nmol phospholipid g–1 soil at the 1.3–9.0 cm depth. The activity of β-glucosidase estimated on samples from 0–1.3 cm and 1.3–9.0 cm depths, and dehydrogenase activity estimated on samples from 1.3–9.0 cm were significantly increased by leaf mulching and N fertilizer application. Changes in microbial community composition, as indicated by phospholipid fatty acid methyl ester analysis, appear to be due to seasonal variations and did not reflect changes due to N or leaf amendment treatments. There were no negative effects of tree leaf mulching into turfgrass and early data suggest this practice will improve soil chemical, physical, and biological structure.

Core Cultivation of a Putting Green with Hollow and Solid Tines

AbstractMost turfgrass soil cultivation research has emphasized water infiltration and thatch responses, but has provided limited information regarding detailed soil and rooting responses to different cultivation methods. This study evaluated cultivation effects on soil physical properties and turf growth of a ‘Penneagle’ creeping bentgrass (Agrostis palustris Huds.) putting green. Cultivation, utilizing vertically operating hollow (HTC) or solid (STC) tines, was applied over a 3‐yr period on a loamy sand soil (modified fine‐loamy, mixed, mesic, Typic Hapludalfs). Cultivation treatments were applied on noncompacted and compacted plots, and at soil moisture potential ranges of −40 to −60 kPa (moist) or −2 to −4 kPa (wet). Saturated water conductivity and air porosity was 49 and 21% greater, respectively, with HTC than STC. After three seasons, wet soil cultivation reduced saturated hydraulic conductivity 31% compared to moist soil cultivation. Cultivation reduced penetration resistance 45% at the 5‐cm depth compared to noncultivated plots in compacted soil, but the benefit was transient particularly on STC plots. Hollow tine cultivation under wet soil conditions yielded the best turf quality. Surface root weight density was lowered 20% with cultivation on compacted soil by the end of the study. Hollow tine cultivation lowered the organic matter fraction of the thatch/mat layer 0.24 kg kg−1, but increased total organic matter content 150 g m−2 compared to solid tine cultivation. Solid tine cultivation provided short term benefits, required repeated application to be effective in management of soil compaction, and exhibited the potential for development of a cultivation pan.

Microbial degradation of propoxur in turfgrass soil.

This study was conducted to determine the degradation rates in turfgrass soil over a 12-month period after a single field application of propoxur and to isolate microorganisms from the soil capable of degrading the insecticide. Soil samples were collected from a turfgrass experimental site near Fort Lauderdale, FL one week before the field application of propoxur, and over a 12-month period after the field application. Mineralization rates in surface (0-15 cm depth) and subsurface (15-30 cm depth) soil samples collected before the field application were low. Mineralization in surface and subsurface samples collected 1, 6 and 8 months after the field application was much higher than for corresponding samples collected before the field application. Mineralization in the subsurface samples collected 12 months after the field application had reverted back to the similar rate for the corresponding sample collected before field application. Half-life values (t1/2) for propoxur showed similar trends to the results of mineralization. After a single application of propoxur, degradation in turfgrass soil was enhanced. Such enhancement lasted less than 12 months for the subsurface, but more than 12 months for the surface. A strain of Arthrobacter sp. capable of degrading propoxur was isolated from the soil.

Gas-liquid chromatographic analysis of oxadiazon residues in turfgrass thatch and soil using a solid-phase extraction technique

Abstract A simple and inexpensive technique for analysis of oxadiazon (5‐tert‐butyl‐3‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐1,3,4,‐oxadiazol‐2(3H)‐=one) residues in thatch and soil involving solid‐phase extraction/purification and final gas‐liquid chromatographic determination with nitrogen‐phosphorus specific detection has been developed. The method, sensitive to 0.08ppm for thatch and 0.04ppm for soil, significantly reduces the use of organic solvents and labor, and allows simultaneous analysis of multiple samples.

Residue of Bensulide in Turfgrass Soil Following Annual Treatments for Crabgrass Control1

AbstractA series of experiments was used to evaluate bensulide treatments in terms of crabgrass control, soil residue, leaching and effect on seedling establishment. Annual treatments of 16.8 kg/ha (15 lb/acre) of bensulide gave continuous preemergence control of crabgrass (reseeded annually) in bentgrass turf. The turfgrass vigor was improved through crabgrass control as compared to untreated plots with competing crabgrass. Bensulide residue in the soil was determined by a bioassay developed by measuring the rate of root growth of milo from seed. With the granular formulation large amounts of bensulide were found in the soil at eleven months after the fourth annual application. Detectable quantities were obtained to depths of 12.75 cm. The emulsifiable concentrate treatments did not persist for eleven months following the fourth application in detectable quantities in the soil.Soil properties affected the response of milo to bensulide. It was demonstrated that more bensulide was required to produce injury to milo roots in soil from the surface layer (0‐2.5 cm) than in soil from lower layers. Milo phytotoxicity was inversely related to organic matter and nutrient content of the soil.Three dates of planting five turfgrass species following herbicide treatment were evaluated. Bensulide affected all species planted on the day of treatment but all species emerged well when planted 30 to 60 days after herbicide application to the soil surface.