Effects of Subsurface Banding and Broadcast of Poultry Litter and Cover Crop on Soil Microbial Populations.

Agronomic management is aimed at managing the crop environment to maximize crop yield, but soil biology is often ignored. This study aimed to compare the application of poultry litter via broadcast and subsurface banding versus standard inorganic fertilizer to cotton ( L.) and their effects on soil bacterial populations and fecal indicator bacteria. The study comprised a randomized complete block design, with fertilizer and time of application as treatment effects and cover crop as a main effect. Soil cores were collected and analyzed from 2008 to 2014. Fecal indicator bacteria were at detection limits for all treatments, where the integron 1 gene was significantly elevated in litter plots. There were few differences between litter application approaches, but both significantly increased key biogeochemical genes over control plots, whereas a cover crop only increased soil moisture and urease C. Data suggested a positive residual effect of litter application with 16S, phosphatase A, and urease C genes elevated over controls, but similar to standard fertilizer plots. High-throughput 16S ribosomal RNA analysis suggested increased diversity and enrichment indices in litter and standard fertilizer over untreated control plots. Litter and standard fertilizer effects persisted 4 and 2 yr after application, respectively, as evidenced by residual library community structures. This study demonstrated the positive effects of litter application on the soil bacterial community when compared with untreated control plots. Some differences between standard fertilization and litter practices were noted and suggest that there is a positive residual effect on soil microbial populations associated with both practices.

School, Friends, and Substance Use: Gender Differences on the Influence of Attitudes Toward School and Close Friend Networks on Cannabis Involvement.

The school environment is extremely salient in young adolescents' lives. Adolescents who have unfavorable attitudes toward school and teachers are at elevated risk for dropping out of school and engaging in behavioral health risks. Peer network health-a summation of the positive and negative behaviors in which one's close friend group engages-may be one way by which attitudes toward school exert influence on youth substance use. Utilizing a sample of 248 primarily African-American young urban adolescents, we tested a moderated mediation model to determine if the indirect effect of attitude to school on cannabis involvement through peer network health was conditioned on gender. Attitude toward school measured at baseline was the predictor (X), peer network health measured at 6 months was the mediator (M), cannabis involvement (including use, offers to use, and refusals to use) measured at 24 months was the outcome (Y), and gender was the moderator (W). Results indicated that negative attitudes toward school were indirectly associated with increased cannabis involvement through peer network health. This relationship was not moderated by gender. Adolescents in our sample with negative attitudes toward school were more likely to receive more offers to use cannabis and to use cannabis more frequently through the perceived health behaviors of their close friends. Implications from these results point to opportunities to leverage the dynamic associations among school experiences, friends, and cannabis involvement, such as offers and use.

The Dynamic Role of Urban Neighborhood Effects in a Text-Messaging Adolescent Smoking Intervention.

INTRODUCTION: Neighborhood features such as the density of tobacco outlets relative to one's home and evaluations of safety of one's activity space (routine locations), are known to influence health behaviors. Understanding the time-varying nature of these aspects of the urban ecology provides unique insights into the dynamic interactions of individuals and their environments. METHODS: The present study tested the time-varying effects of tobacco outlets and perceived safety within a randomized controlled trial of an adolescent text-messaging smoking intervention. We used ecological momentary assessment data (EMA) from an automated text-messaging smoking cessation randomized trial with 197 primarily African American urban adolescents. We employed a time-varying effect model to estimate the effects of density of tobacco outlets within one-half mile of participants' home locations (time-invariant covariate) and evaluations of safety of their activity space (time-varying covariate) on momentary smoking over 6 months by treatment condition. The time-varying effect model approach models behavioral change and associations of coefficients expressed dynamically and graphically represented as smooth functions of time. RESULTS: Differences in trajectories of smoking between treatment conditions were apparent over the course of the study. During months 2 and 6, the association between tobacco outlet density and smoking was significantly stronger in the control condition, suggesting treatment dampens this association during these time periods. The intervention also significantly reduced the association of perceived safety and smoking among the treatment condition during months 3 through 6. CONCLUSIONS: Results support testing the time-varying effects of urban ecological features and perceptions of safety among adolescents in text-based smoking cessation interventions. IMPLICATIONS: This study makes a unique contribution towards understanding the time-varying effects of urban neighborhoods on adolescent tobacco use within the context of a text-delivered intervention. Helping to adjust the long-held conceptualization of intervention effects as a static outcome, to that of a dynamic, time-varying process, is an important contribution of this study. The ability to specify when behavioral change occurs within the context of a randomized control trial provides understanding into the time-varying treatment effects of text-based smoking intervention. For example, researchers can modify the intervention to have strategically timed booster sessions that align with when the odds of smoking begin to increase in order to provide more precise treatment. The current study results show that increasing support to participants during months 2 and 4 may help suppress smoking over the course of a 6-month intervention.

Text Message Delivered Peer Network Counseling for Adolescent Smokers: A Randomized Controlled Trial.

Although adolescent tobacco use has declined in the last 10 years, African American high school seniors' past 30-day use has increased by 12 %, and as they age they are more likely to report lifetime use of tobacco. Very few urban youth are enrolled in evidenced-based smoking prevention and cessation programming. Therefore, we tested a text messaging smoking cessation intervention designed to engage urban youth through an automated texting program utilizing motivational interviewing-based peer network counseling. We recruited 200 adolescents (90.5 % African American) into a randomized controlled trial that delivered either the experimental intervention of 30 personalized motivational interviewing-based peer network counseling messages, or the attention control intervention, consisting of text messages covering general (non-smoking related) health habits. All adolescents were provided smart phones for the study and were assessed at baseline, and at 1, 3, and 6 months post intervention. Utilizing repeated measures general linear models we examined the effects of the intervention while controlling for race, gender, age, presence of a smoker in the home, and mental health counseling. At 6 months, participants in the experimental condition significantly decreased the number of days they smoked cigarettes and the number of cigarettes they smoked per day; they significantly increased their intentions not to smoke in the future; and significantly increased peer social support among girls. For boys, participants in the experimental condition significantly reduced the number of close friends in their networks who smoke daily compared to those in the control condition. Effect sizes ranged from small to large. These results provide encouraging evidence of the efficacy of text messaging interventions to reduce smoking among adolescents and our intervention holds promise as a large-scale public health preventive intervention platform.

Subsurface Band Application of Poultry Litter and Its Influence on Phosphorus Concentration and Retention after Runoff from Permanent Pastures.

Excessive phosphorus (P) loss from agricultural fields is a major cause of eutrophication to rivers, lakes, and streams. To mitigate P loss after poultry litter (PL) applications, technology is being developed to apply litter below the soil surface. Thus, research was conducted to evaluate the effects of subsurface PL banding on soil P under pasture management. Treatments consisted of surface-broadcasted or subsurface-banded PL (38 cm apart) at 9 Mg ha, surface-broadcasted commercial fertilizer (CF; urea and triple superphosphate blend) at N (330 kg N ha) and P (315 kg N ha) application rates equivalent to PL, and a nonfertilized control. Runoff events lasting 40 min were simulated in bermudagrass ( L.) pastures on common soil types of the Coastal Plain and Piedmont regions. One day later, Mehlich-1 and water-soluble P concentrations in soil were measured at depths of 0 to 5 cm and 5 to 10 cm to determine P distribution and movement. The greatest P concentrations were observed at the shallow depth for all treatments. Phosphorus measurements at the point of application for PL bands were greater than for the surface-applied treatments (PL and CF) and control. Measurements between subsurface PL bands were slightly higher than the control but were statistically similar, suggesting that this application method can abate short-term P movement. Results obtained from this study show that subsurface band applying PL could increase P retention and reduce movement by precluding contact between surface water and litter nutrients.

Development and Outcomes of a Text Messaging Tobacco Cessation Intervention With Urban Adolescents.

BACKGROUND: This paper describes the development of an urban adolescent text messaging tobacco cessation intervention and preliminary findings from a randomized, controlled trial. The authors successfully adapted a face-to-face intervention into a personalized, automated, and interactive 5-day texting protocol. METHODS: Respondent-driven sampling was used beginning at a community substance abuse facility. Seventy-two tobacco-dependent adolescents were randomized into an automated computer texting program that delivered either the experimental condition of 30 motivational interviewing- and social network counseling-based personalized messages or the attention control condition consisting of a texting program covering general (non-smoking-related) health habits. All teens were provided smartphones for the study and were assessed at baseline and at 1, 3, and 6 months post intervention. Analyses examined condition×time interactions. RESULTS: At 6 months, the experimental condition decreased the number of cigarettes smoked in the past 30 days, increased intentions not to smoke in the future, and increased peer social support compared with controls. Effect sizes were moderate to large. CONCLUSIONS: These findings are unique, as they target urban adolescents with a mobile health format and add to the growing literature on the efficacy of text-delivered interventions.

Text messaging to increase readiness to change alcohol use in college students.

We tested the feasibility and effectiveness of an alcohol counseling intervention delivered via personalized text messages for college students with problem alcohol use. College students aged 18-23 completed online substance use and mental health questionnaires that served as a screening tool for problem alcohol use. We invited students who screened positive to be randomized to intervention (n = 8) or control groups (n = 10) and assessed them at 1 month after they received their last text message. The intervention group received between four and six text messages daily for 4 days that required brief participant responses during the week following the web-based baseline assessment. Participants in the intervention group could also request booster texts for additional support. We personalized all texts, using data collected at baseline. Using a repeated measures ANOVA, we found that compared to the control group, the intervention group increased in readiness to change from baseline to follow-up (p < .01). Other promising trends were an increase in the intervention relative to the control group's confidence in their ability to change drinking behavior, and an increase in intentions to reduce alcohol use. These exploratory results indicate that the automated texting program we developed works well with college students and that text messaging as a means to deliver preventive interventions is a promising delivery platform.

Nutrient loss in leachate and surface runoff from surface-broadcast and subsurface-banded broiler litter.

Subsurface band application of poultry litter has been shown to reduce the transport of nutrients from fields in surface runoff compared with conventional surface broadcast application. Little research has been conducted to determine the effects of surface broadcast application and subsurface banding of litter on nutrients in leachate. Therefore, a field experiment was conducted to determine the effects of subsurface band application and surface broadcast application of poultry litter on nutrient losses in leachate. Zero-tension pan and passive capillary fiberglass wick lysimeters were installed in situ 50 cm beneath the soil surface of an established tall fescue ( Schreb.) pasture on a sandy loam soil. The treatments were surface broadcast and subsurface-banded poultry litter at 5 Mg ha and an unfertilized control. Results of the rainfall simulations showed that the concentrations of PO-P and total phosphorus (TP) in leachate were reduced by 96 and 37%, respectively, in subsurface-banded litter treatment compared with the surface-applied litter treatment. There was no significant difference in PO-P concentration between control and subsurface-banded litter treatment in leachate. The trend in the loading of nutrients in leachate was similar to the trend in concentration. Concentration and loading of the nutrients (TP, PO-P, NH-N, and NO-N) in runoff from the subsurface-banded treatment were significantly less than for the surface-applied treatment and were similar to those from control plots. These results show that, compared with conventional surface broadcast application of litter, subsurface band application of litter can greatly reduce loss of P in surface runoff and leachate.

Phosphorus runoff losses from subsurface-applied poultry litter on coastal plain soils.

The application of poultry litter to soils is a water quality concern on the Delmarva Peninsula, as runoff contributes P to the eutrophic Chesapeake Bay. This study compared a new subsurface applicator for poultry litter with conventional surface application and tillage incorporation of litter on a Coastal Plain soil under no-till management. Monolith lysimeters (61 cm by 61 cm by 61 cm) were collected immediately after litter application and subjected to rainfall simulation (61 mm h(-1) 1 h) 15 and 42 d later. In the first rainfall event, subsurface application of litter significantly lowered total P losses in runoff (1.90 kg ha(-1)) compared with surface application (4.78 kg ha(-1)). Losses of P with subsurface application were not significantly different from disked litter or an unamended control. By the second event, total P losses did not differ significantly between surface and subsurface litter treatments but were at least twofold greater than losses from the disked and control treatments. A rising water table in the second event likely mobilized dissolved forms of P in subsurface-applied litter to the soil surface, enriching runoff water with P. Across both events, subsurface application of litter did not significantly decrease cumulative losses of P relative to surface-applied litter, whereas disking the litter into the soil did. Results confirm the short-term reduction of runoff P losses with subsurface litter application observed elsewhere but highlight the modifying effect of soil hydrology on this technology's ability to minimize P loss in runoff.

The spatial accuracy of geographic ecological momentary assessment (GEMA): Error and bias due to subject and environmental characteristics.

BACKGROUND: Geographic ecological momentary assessment (GEMA) combines ecological momentary assessment (EMA) with global positioning systems (GPS) and geographic information systems (GIS). This study evaluates the spatial accuracy of GEMA location data and bias due to subject and environmental data characteristics. METHODS: Using data for 72 subjects enrolled in a study of urban adolescent substance use, we compared the GPS-based location of EMA responses in which the subject indicated they were at home to the geocoded home address. We calculated the percentage of EMA locations within a sixteenth, eighth, quarter, and half miles from the home, and the percentage within the same tract and block group as the home. We investigated if the accuracy measures were associated with subject demographics, substance use, and emotional dysregulation, as well as environmental characteristics of the home neighborhood. RESULTS: Half of all subjects had more than 88% of their EMA locations within a half mile, 72% within a quarter mile, 55% within an eighth mile, 50% within a sixteenth of a mile, 83% in the correct tract, and 71% in the correct block group. There were no significant associations with subject or environmental characteristics. CONCLUSIONS: Results support the use of GEMA for analyzing subjects' exposures to urban environments. Researchers should be aware of the issue of spatial accuracy inherent in GEMA, and interpret results accordingly. Understanding spatial accuracy is particularly relevant for the development of 'ecological momentary interventions' (EMI), which may depend on accurate location information, though issues of privacy protection remain a concern.

Neighborhood disorder, peer network health, and substance use among young urban adolescents.

BACKGROUND: The current study investigated the moderating effect of peer networks on neighborhood disorder's association with substance use in a sample of primarily African American urban adolescents. METHODS: A convenience sample of 248 adolescents was recruited from urban health care settings and followed for two years, assessing psychological, social, and geographic risk and protective characteristics. A subset of 106 substance using participants were used for the analyses. A moderation model was tested to determine if the influence of neighborhood disorder (percent vacant housing, assault index, percent single parent headed households, percent home owner occupied, percent below poverty line) on substance use was moderated by peer network health (sum of peer risk and protective behaviors). RESULTS: Evidence for hypothesized peer network moderation was supported. A latent growth model found that peer network health is most strongly associated with lower baseline substance use for young adolescents residing in more disordered neighborhoods. Over the course of two years (ages approximately 14-16) this protective effect declines, and the decline is stronger for more disordered neighborhoods. CONCLUSIONS: Understanding the longitudinal moderating effects of peer networks within high-risk urban settings is important to the development and testing of contextually sensitive peer-based interventions. RESULTS: suggest that targeting the potential protective qualities of peer networks may be a promising approach for interventions seeking to reduce substance use, particularly among younger urban adolescents living in high-risk neighborhoods.

The role of tobacco outlet density in a smoking cessation intervention for urban youth.

This study investigates the role of tobacco outlet density in a randomized controlled trial of a text messaging-based smoking cessation intervention conducted among a sample of 187 primarily African American youth in a midsize U.S. city. A moderated mediation model was used to test whether the indirect effect of residential tobacco outlet density on future smoking was mediated by the intention to smoke, and whether this indirect effect differed between adolescents who received the intervention and those who did not. Results indicated that tobacco outlet density is associated with intention to smoke, which predicts future smoking, and that the indirect effect of tobacco outlet density on future smoking is moderated by the intervention. Tobacco outlet density and the intervention can be viewed as competing forces on future smoking behavior, where higher tobacco outlet density acts to mitigate the sensitivity of an adolescent to the intervention's intended effect. Smoking cessation interventions applied to youth should consider tobacco outlet density as a contextual condition that can influence treatment outcomes.

Does substance use moderate the association of neighborhood disadvantage with perceived stress and safety in the activity spaces of urban youth?

BACKGROUND: This study investigates the association of activity space-based exposure to neighborhood disadvantage with momentary perceived stress and safety, and the moderation of substance use on those associations, among a sample of 139 urban, primarily African American, adolescents. METHOD: Geospatial technologies are integrated with Ecological Momentary Assessment (EMA) to capture exposure to neighborhood disadvantage and perceived stress and safety in the activity space. A relative neighborhood disadvantage measure for each subject is calculated by conditioning the neighborhood disadvantage observed at the EMA location on that of the home neighborhood. Generalized estimating equations (GEE) are used to model the effect of relative neighborhood disadvantage on momentary perceived stress and safety, and the extent to which substance use moderates those associations. RESULTS: Relative neighborhood disadvantage is significantly associated with higher perceived stress, lower perceived safety, and greater substance use involvement. The association of relative neighborhood disadvantage with stress is significantly stronger among those with greater substance use involvement. CONCLUSION: This research highlights the value of integrating geospatial technologies with EMA and developing personalized measures of environmental exposure for investigating neighborhood effects on substance use, and suggests substance use intervention strategies aimed at neighborhood conditions. Future research should seek to disentangle the causal pathways of influence and selection that relate neighborhood environment, stress, and substance use, while also accounting for the role of gender and family and peer social contexts.

Parents, Peers, and Places: Young Urban Adolescents' Microsystems and Substance Use Involvement.

Limited research is available that explains complex contextual and interactive effects of microsystems such as family relationships, peer networks, and place-based influences have on urban adolescent substance use. We contend that research into these complex processes is improved by integrating psychological, social, and geographic data to better understand urban adolescent substance use involvement. Accordingly, we tested a longitudinal, 3-way moderation model to determine if the direct effect of teen-parent relationships on substance use involvement is moderated by peer network characteristics, which in turn is moderated by the risk and protective attributes within urban adolescents' activity spaces, among a sample of 248 adolescents. Results revealed that peer networks moderate the effects of relations with parents on substance use involvement for those adolescents with higher levels of risk attributes within their activity space, but not for those who spend time in locations with less risk. Thus, the teen-parent relationship interacts with peer net-work characteristics, for those urban adolescents whose activity space is constituted within high-risk environments. We conclude that peer networks have important interactive effects with family relationships that influence substance use, and that this is particularly salient for young adolescents who are exposed to risky environments. This finding underscores the importance of continued study into the interrelations among microsystems of urban adolescents, and provides further support that substance use is a social practice that is constituted within the unique geography of young adolescents' lives.

Real-Time Readiness to Quit and Peer Smoking within a Text Message Intervention for Adolescent Smokers: Modeling Mechanisms of Change.

The psychological construct, readiness to change, is established as a central construct within behavioral change theories such as motivational interviewing (MI). Less is known about the interplay of mechanisms for change within adolescent treatment populations. Understanding the timing and interactive influence that adolescents' readiness to stop smoking and peer smoking have on subsequent tobacco use is important to advance intervention research. Toward this end, we used ecological momentary assessment (EMA) data from an automated texting smoking intervention randomized controlled trial to model the interactive effects of readiness to stop smoking and friends smoking on adolescent tobacco use. Two hundred adolescents were randomized into experimental treatment or attention control conditions, provided smart phones, and were followed for 6 months. African American youth represented the majority of the sample. We collected monthly EMA data for 6 months on friends smoking and readiness to stop smoking as well as survey outcome data. We tested a moderated mediation model using bias corrected bootstrapping to determine if the indirect effect of treatment on cigarettes smoked through readiness to stop smoking was moderated by friends smoking. Findings revealed that readiness to stop smoking mediated the effects of treatment on cigarettes smoked for those adolescents with fewer friends smoking, but not for those with more friends smoking. These results support importance of peer-focused interventions with urban adolescents and provide target mechanisms for future research.

Time-varying effects of a text-based smoking cessation intervention for urban adolescents.

INTRODUCTION: Craving to smoke is understood as an important mechanism for continued smoking behavior. Identifying how smoking interventions operate on craving with particular populations is critical for advancing intervention science. This study's objective was to investigate the time-varying effect of a text-delivered smoking cessation intervention. METHODS: Toward this end, we used ecological momentary assessment (EMA) data collected from a five-day, automated text-messaging smoking cessation randomized clinical trial with 200 urban adolescents. We employed a time-varying effect model (TVEM) to estimate the effects of stress (time-varying covariate) and baseline nicotine dependence level (time-invariant covariate) on craving over six months by treatment condition. The TVEM approach models behavioral change and associations of coefficients expressed dynamically and graphically represented as smooth functions of time. RESULTS: Controlling for gender, age, and current smoking, differences in trajectories of craving between intervention and control conditions were apparent over the course of the study. During months 2 to 3, the association between stress and craving was significantly stronger among the control group, suggesting treatment dampens this association during this time period. The intervention also reduced the salience of baseline dependence among treatment adolescents, with craving being reduced steadily over time, while the control group increased craving over time. CONCLUSIONS: These results provide insight into the time-varying nature of treatment effects for adolescents receiving a text-based smoking cessation intervention. The ability to specify when in the course of an intervention the effect is strongest is important in developing targeted and adaptive interventions that can adjust strategically with time.

Young adolescents' perceived activity space risk, peer networks, and substance use.

Adolescent substance use is a developmentally contingent social practice that is constituted within the routine social-environment of adolescents' lives. Few studies have examined peer networks, perceived activity space risk (risk of substance use at routine locations), and substance use. We examined the moderating influence of peer network characteristics on the relationship between perceived activity space risk and substance use among a sample of 250 urban adolescents. Significant interactions were found between peer networks and perceived activity space risk on tobacco and marijuana use, such that protective peer networks reduced the effect of activity place risk on substance use. A significant 3-way interaction was found on marijuana use indicating that gender moderated peer network's effect on activity space risk. Conditional effect analysis found that boys' peer networks moderated the effect of perceived activity space risk on marijuana use, whereas for girls, the effect of perceived activity space risk on marijuana use was not moderated by their peer networks. These findings could advance theoretical models to inform social-environmental research among adolescents.

Peer Network Counseling with Urban Adolescents: A Randomized Controlled Trial with Moderate Substance Users.

Close peer networks can affect adolescents' health behaviors by altering their social environments, and thus their risk for and protection against substance use involvement. We tested a 20 minute intervention named Peer Network Counseling that integrates motivational interviewing and peer network strategies with 119 urban adolescents who reported occasional or problem substance use. Adolescents presenting at primary care clinic were randomized to intervention or control conditions and followed for 6 months. Mixed-effect latent growth models were used to evaluate intervention effects on trajectories of alcohol and marijuana use, offers to use substances, and moderation models to test for interactions between intervention condition and peer network characteristics. A significant intervention effect was found for boys for offers to use alcohol from friends (p<.05), along with a trend significant effect for alcohol use (p<.08). Intervention was more effective in reducing marijuana use, vs. control, for participants with more peer social support (p<.001) and with more peer encouragement for prosocial behavior (school, clubs, sports, religious activities); however, intervention did not affect these network characteristics. Results provide support to continue this line of research to test brief interventions that activate protective peer network characteristics among at-risk adolescents, while also raising some interesting gender-based intervention questions for future research.