IMPACT OF A TURFGRASS SYSTEM ON NUTRIENT LOADINGS TO SURFACE WATER1

ABSTRACT: Turfgrass systems are one of the most intensively managed land uses in the United States. Establishment and maintenance of high quality turfgrass usually implies substantial inputs of water, nutrients, and pesticides. The focus of this work was to quantify the concentration and loading of a typically maintained municipal turfgrass environment on surface water. Water quantity and quality data were collected from a golf course in Austin, Texas, and analyzed for a 13‐month period from March 20, 1998, to April 30, 1999. Twenty‐two precipitation events totaling 722 mm, produced an estimated 98 mm of runoff. Nutrient analysis of surface runoff exiting the course exhibited a statistically significant (p < 0.05) increase in median nitrate plus nitrite nitrogen (NO₃+NO₂‐N) concentration compared to runoff entering the course, a statistically significant decrease in ammonia nitrogen (NH₄‐N), but no difference in orthophosphate (PO₄‐P). During the 13‐month period, storm runoff contributed an estimated 2.3 kg/ha of NO₃+NO₂‐N and 0.33 kg/ha of PO₄‐P to the stream. Storm flow accounted for the attenuation of 0.12 kg/ha of NH₄‐N. Baseflow nutrient analysis showed a statistically significant increase in median NO₃+NO₂‐N, a significant reduction in NH₄‐N, and no change in PO₄‐P. Estimated NO₃+NO₂‐N mass in the baseflow was calculated as 4.7 kg/ha. PO₄‐P losses were estimated at 0.06 kg/ha, while 0.8 kg/ha of NH₄‐N were attenuated in baseflow over the study period. Even though nutrient concentrations exiting the system rarely exceeded nutrient screening levels, this turfgrass environment did contribute increased NO₃+NO₂‐N and PO₄‐P loads to the stream. This emphasizes the need for parallel studies where management intensity, soil, and climate differ from this study and for golf course managers to utilize an integrated management program to protect water quality while maintaining healthy turfgrass systems.     

Comparison of Machine Learning Models Performance on Simulating Reservoir Outflow: A Case Study of Two Reservoirs in Illinois,U.S.A.

Reservoir outflow is an important variable for understanding hydrological processes and water resource management. Natural streamflow variation, in addition to the streamflow regulation provided by dams and reservoirs, can make streamflow difficult to understand and predict. This makes them a challenge to accurately simulate hydrologic processes at a daily scale. In this study, three Machine Learning (ML) algorithms, Random Forest (RF), Support Vector Machine (SVM), and Artificial Neural Network (ANN), were examined and compared to model reservoir outflow. Past, current, and future hydrologic and meteorological data were used as model inputs, and the outflow of next day was used as prediction. Simulation results demonstrated that all three models can reasonably simulate reservoir outflow. For Carlyle Lake, the coefficient of determination and Nash–Sutcliffe efficiency were each close to one for the three models. The coefficient of determination, relative mean bias, and root mean square error indicated that the SVM performed better than the RF and ANN, but the SVM output displayed a larger relative mean bias than that from RF and ANN. For Lake Shelbyville, the ANN model performed better than RF and SVM when considering the coefficient of determination, Nash–Sutcliffe efficiency, relative mean bias, and root mean square error. The study results demonstrate that the three ML algorithms (RF, SVM, and ANN) are all promising tools for simulating reservoir outflow. Both the accuracy and efficacy of the three ML algorithms are considered to support practitioners in planning reservoir management.     

Examination of the combined effects of work values and early work experiences on organizational commitment

We tested the hypothesis that the influence of early work experiences on organization commitment would be moderated by the value employees place on these experiences. We measured work values in two samples of recent university graduates prior to organizational entry, and obtained measures of commensurate work experiences and three forms of commitment (affective, continuance, and normative: Allen and Meyer, 1990) on different occasions following entry. Regression analyses revealed that values and experiences did interact in the prediction of affective commitment and normative commitment, but that the nature of the interaction was different for different work value/experience combinations. The findings provide some challenge to the common sense assumption that positive work experiences will have the strongest effect on commitment among those who most value such experiences. Implications for research and practice are discussed. © 1998 John Wiley & Sons, Ltd.     

Community-based disaster preparedness and climate adaptation: local capacity-building in the Philippines

Community-based disaster preparedness (CBDP) approaches are increasingly important elements of vulnerability reduction and disaster management strategies. They are associated with a policy trend that values the knowledge and capacities of local people and builds on local resources, including social capital. CBDP may be instrumental not only in formulating local coping and adaptation strategies, but also in situating them within wider development planning and debates. In theory, local people can be mobilised to resist unsustainable (vulnerability increasing) forms of development or livelihood practices and to raise local concerns more effectively with political representatives. This paper focuses on the potential of CBDP initiatives to alleviate vulnerability in the context of climate change, and their limitations. It presents evidence from the Philippines that, in the limited forms in which they are currently employed, CBDP initiatives have the potential both to empower and disempower, and warns against treating CBDP as a panacea to disaster management problems.     

ASsessment Of Alcohol Ethoxylate Surfactants And Fatty Alcohols Mixtures In River Sediments And Prospective Risk Assessment

A feasible and relatively readily available analytical method was adapted for the assessment of alcohol ethoxylates (AE) and fatty alcohols (FA) in sediments. This study illustrates the simultaneous measurement of 38 of 114 possible alcohol ethoxylate ethoxymers (AE) and fatty alcohols (FA) found in commercially important AE products. We predicted toxicity for all identified fractions, as well as the total mixture toxicity, relative to three exposure scenarios via sewage treatment plants (STP) for these widely used chemicals in consumer products and hence generate a preliminary environmental risk screening for AE and FA in sediments. The method is based on derivatization of solvent or solid-phase extracts with 2-fluoro-N-methylpyridinium p-toluenesulfonate (Pyr+). The derivatized extracts were analyzed with liquid chromatography/mass spectrometry (LC/MS) operating in the positive ion electrospray mode. The extraction efficiency of AE and FA in three different sediments of varying composition was evaluated with spike-recovery studies, ranging from 64% to 80%. The detection limits for individual ethoxymers typically ranged from 1 to 5ngg⁻¹on a dry weight basis. The mean limit of detection (LOD) was 6ngg⁻¹and the median LOD was 3ngg⁻¹. AE and FA in sediments were found to be stable for two weeks if preserved with 3% (v/v) formalin and stored at 4–6^∘C. Based on equilibrium partitioning, background concentrations of AE and FA were predicted to be below concentrations known to elicit chronically toxic effects. Total worst case mixture toxicities for all AE ethoxymers combined with FA were predicted to result in a risk quotient less than 0.6. Activated sludge treatment (STP) significantly reduced the release of total AE and FA by four-fold, suggesting that the total mixture risk quotient would be < 0.15 for sediment dependent organisms.     

Soil and surface runoff phosphorus relationships for five typical USA midwest soils

Excessively high soil P can increase P loss with surface runoff. This study used indoor rainfall simulations to characterize soil and runoff P relationships for five Midwest soils (Argiudoll, Calciaquaoll, Hapludalf, and two Hapludolls). Topsoil (15-cm depth, 241-289 g clay kg(-1) and pH 6.0-8.0) was incubated with five NH4H2PO4 rates (0-600 mg P kg(-1)) for 30 d. Total soil P (TPS) and soil-test P (STP) measured with Bray-P1 (BP), Mehlich-3 (M3P), Olsen (OP), Fe-oxide-impregnated paper (FeP), and water (WP) tests were 370 to 1360, 3 to 530, 10 to 675, 4 to 640, 7 to 507, and 2 to 568 mg P kg(-1), respectively. Degree of soil P saturation (DPS) was estimated by indices based on P sorption index (PSI) and STP (DPSSTP) and P, Fe, and Al extracted by ammonium oxalate (DPSox) or Mehlich-3 (DPSM3). Soil was packed to 1.1 g cm(-3) bulk density in triplicate boxes set at 4% slope. Surface runoff was collected during 75 min of 6.5 cm h(-1) rain. Runoff bioavailable P (BAP) and dissolved reactive P (DRP) increased linearly with increased P rate, STP, DPSox, and DPSM3 but curvilinearly with DPSSTP. Correlations between DRP or BAP and soil tests or saturation indices across soils were greatest (r > or = 0.95) for FeP, OP, and WP and poorest for BP and TPS (r = 0.83-0.88). Excluding the calcareous soil (Calciaquoll) significantly improved correlations only for BP. Differences in relationships between runoff P and the soil tests were small or nonexistent among the noncalcareous soils. Routine soil P tests can estimate relationships between runoff P concentration and P application or soil P, although estimates would be improved by separate calibrations for calcareous and noncalcareous soils.     

Remediation of chloroform in fine-textured soil using zero-valent iron

Chloroform, a probable human carcinogen, is mainly produced anthropogenically for industrial use and may be released to the environment from a large number of sources related to its manufacture and use, including pulp and paper mills, hazardous waste sites, and sanitary landfills. Remediation of chloroform through conventional technologies has been met with limited success due to the conditions required and the formation of hazardous substances such as dichloromethane. The objective of this study was to investigate chloroform reduction in multicontaminated fine-textured soil using zero-valent iron (Fe⁰) in anaerobic microcosms. Four amended matrices were tested: simple matrix control (glass beads), soil matrix control (glass beads + soil), Fe⁰ in a simple matrix (glass beads + Fe⁰), and Fe⁰ in a soil matrix (soil + Fe⁰). Headspace chloroform and its transformation products dichloromethane, chloromethane, and methane were measured over 230 days and during short intervals in the initial 3 days. Chloroform (~0.3 mM initial mass) persisted in both control microcosms but was completely transformed in microcosms containing soil + Fe⁰ by 12 h and glass beads + Fe⁰ by 48 h. Reductive dechlorination of chloroform occurred with simultaneous production of dichloromethane (~0.11 to 0.14 mM mass) and chloromethane (~0.02 to 0.13 mM mass). Little methane (~0.07 to 0.26 μM mass) production as an end product of chloroform reduction was observed in microcosms amended with Fe⁰. Produced dichloromethane and chloroform almost disappeared by 230 days. The results showed a complete chloroform transformation pathway that has good potential for the remediation of chlorinated compounds in fine-textured soil. The role of soil clay minerals in redox reactions can be further investigated to improve the reductive dechlorination of chlorinated compounds in contaminated environments.     

The virtue of compassion in compassionate conservation

The role of ethics is becoming an increasingly important feature of biodiversity conservation dialogue and practice. Compassionate conservationists argue for a prohibition of, or at least a strong presumption against, the adoption of conservation policies that intentionally harm animals. They assert that to be compassionate is to care about animals and that it is antithetical to caring for animals to intentionally harm them. Compassionate conservationists thus criticize many existing conservation practices and policies. Two things together challenge the philosophical foundation of compassionate conservation. First, compassionate conservationists ground their theory in virtue ethics, yet virtue ethics permits exceptions to moral rules, so there cannot be an in-principle prohibition on adopting intentional harm-inducing policies and practices. But not all compassionate conservationists advocate for a prohibition on intentionally harming animals, only a strong presumption against it. This leads to the second point: compassion can motivate a person to adopt a harm-inducing conservation policy or practice when doing so is the best available option in a situation in which animals will be harmed no matter what policy or practice is adopted. Combining these insights with the empirical observation that conservationists regularly find themselves in tragic situations, we arrive at the conclusion that conservationists may regularly advocate for harm-inducing policies and practices from a position of compassion. Article Impact Statement: Compassionate conservationists should accept that the virtuously compassionate person may adopt harm-causing conservation policies.