Short-term Impacts of Tillage and Fertilizer Treatments on Soil and Root Borne Nematodes and Maize Yield in a Fine Textured Cambisol

Conservation agriculture (CA) based on the principles of minimum soil disturbance, crop residue retention, and crop rotation has been the focus of intensive research in recent years. A study was carried out to determine the effects of tillage and fertilizer on the population densities of plant-parasitic nematodes in maize. Three tillage regimes, (i) basin planting, (ii) rip line seeding, and (iii) conventional tillage, were combined with four fertilizer regimes: (i) no-fertilizer, (ii) low fertilizer rate, (iii) medium fertilizer rate, and (iv) high fertilizer rate. The experiment was arranged as a split plot in randomized complete block design, replicated three times with tillage as the main plot factor and fertilizer as the sub-plot factor. The study was conducted on fine-textured Cambisol soils at Chinhoyi University of Technology farm, Zimbabwe, over two cropping seasons between December 2014 and April 2016. Eight plant-parasitic nematode genera were observed belonging to five groups based on their feeding sites: (i) sedentary endoparasites ( Meloidogyne and Rotylenchulus ), (ii) migratory endoparasites ( Pratylenchus ), (iii) semi-endoparasites ( Scutelonema and Helicotylenchus ), (iv) ectoparasites ( Xiphinema and Trichodorus ), and (v) algal, lichen or moss feeders ( Tylenchus ). In both cropping seasons, semi-endoparasitic nematodes were double under rip line seeding and triple under basin planting compared to conventional tillage. Basin planting had higher plant-parasitic nematode richness than rip line seeding. Nematode densities did not have a measurable effect on maize grain yield. Maize grain yield was higher in rip line seeding (37%) and planting basins (52%) than conventional tillage during 2014/15 cropping season. On the other hand, during 2015/16 cropping season, maize grain yield was 78% and 113% higher in rip line seeding and basin planting, respectively, compared to conventional tillage. The results show that under the environmental and edaphic conditions of this specific study site, semi-endoparasitic nematodes were higher under rip line seeding and basin planting compared to conventional tillage. The authors conclude that (i) plant-parasitic nematode genera exhibited differential responses to different tillage systems but were not affected by fertilizer application, and (ii) in the present study, maize grain yield response under different tillage and fertilizer regimes was overall not related to nematode population density and composition.

Interseason variability of a functional movement test, the 9+ screening battery, in professional male football players

BACKGROUND

The Nine Plus screening battery test (9+) is a functional movement test intended to identify limitations in fundamental movement patterns predisposing athletes to injury. However, the interseason variability is unknown.

AIM

To examine the variability of the 9+ test between 2 consecutive seasons in professional male football players.

METHODS

Asymptomatic Qatar Star League players (n=220) completed the 9+ at the beginning of the 2013 and 2014 seasons. Time-loss injuries in training and matches were obtained from the Aspetar Injury and Illness Surveillance Program. No intervention was initiated between test occasions.

RESULTS

A significant increase in the mean total score of 1.6 points (95% CI 1.0 to 2.2, p<0.001) was found from season 1 (22.2±4.1 (SD)) to season 2 (23.8±3.3). The variability was large, as shown by an intraclass correlation coefficient (ICC) of 0.24 (95% CI 0.11 to 0.36) and a minimal detectable change (MDC) of 8.7 points. Of the 220 players, 136 (61.8%) suffered a time-loss injury between the 2 tests. There was an improvement in mean total scores in the injured (+2.0±0.4 (SE), p<0.001) group but not in the uninjured group (+0.9±0.5, p=0.089). The variability from season 1 to season 2 was large both in the injured (ICC 0.25, 0.09 to 0.40, MDC 8.3) and uninjured (ICC 0.24, 0.02 to 0.43, MDC 9.1) groups.

CONCLUSIONS

The 9+ demonstrated substantial intraindividual variability in the total score between 2 consecutive seasons, irrespective of injury. A change above 8 points is necessary to represent a real change in the 9+ test between seasons.

Injury rate and injury pattern among elite World Cup snowboarders: a 6-year cohort study

BACKGROUND

There is limited knowledge on the injury rate and injury pattern in the different disciplines among elite snowboarders.

OBJECTIVE

The aim of this study was to describe and compare the injury rate and injury pattern among the different International Ski Federation (Fédération Internationale de Ski, FIS) World Cup (WC) snowboard disciplines.

METHODS

We conducted retrospective interviews with FIS WC snowboard athletes at the end of each season in the period 2007-2012, to register all acute injuries sustained during training or competition during the competitive season requiring attention by medical personnel. To calculate the exposure, we obtained information from result lists from the FIS competition database for all WC competitions for each of the interviewed athletes.

RESULTS

We registered a total of 574 injuries among 1432 athletes, accounting for an overall injury rate of 40.1 injuries/100 athlete/season. A total of 171 injuries occurred during the FIS WC competitions, corresponding to 6.4 injuries/1000 runs. During competition, injury risk was highest in snowboard cross with 11.9/1000 runs, followed by 6.3 in halfpipe, 3.6 in big air and 2.8 in parallel giant slalom/parallel slalom (PGS/PSL). Snowboard cross also had the highest risk of severe injuries (>28 days absence). No differences in injury risk were detected between male and female snowboarders. The most commonly injured body part was the knee (17.8%), followed by the shoulder/clavicle (13.4%) and head/face (13.2%). The risk of knee injury (the most common injury type) and head injury was significantly higher in snowboard cross and halfpipe compared to PGS/PSL.

CONCLUSIONS

The risk of injuries was higher in snowboard cross than in halfpipe, big air and PGS/PSL. The most commonly injured body part was the knee. Prevention of snowboard injuries among elite snowboarders should focus on knee injuries, severe injuries and snowboard cross athletes.

Injuries among male and female World Cup alpine skiers

BACKGROUND

Limited knowledge exists on injuries among professional alpine skiers.

OBJECTIVE

To describe the risk of injury and the injury pattern among competitive World Cup alpine skiers during the competitive season.

METHODS

Retrospective interviews were performed with all World Cup athletes from 10 nations at the end of the 2006-7 and 2007-8 winter seasons, and all acute injuries occurring during the 4.5-month competitive season were recorded. If the athlete was not present, their coaches or medical personnel were interviewed.

RESULTS

A total of 191 acute injuries were recorded among 521 World Cup alpine skiers. As many as 86 injuries (45%) occurred during World Cup/World Ski Championship competitions, corresponding to an injury rate of 9.8 injuries per 1000 runs (95% CI 7.8 to 11.9). The injury rate was found to increase with increasing speed (slalom 4.9 injuries per 1000 runs, 95% CI 2.5 to 7.4--giant slalom 9.2, 5.1 to 13.3--super-G 11.0, 5.2 to 16.8--downhill 17.2, 11.6 to 22.7). The most frequently injured body part was the knee, with 68 injuries (36%), and 37 of these were severe. The overall injury rate was higher in males than in females, but not for knee injuries.

CONCLUSIONS

The risk of injury among World Cup athletes in alpine skiing is even higher than previously reported. The knee is the most commonly injured body part and with many severe injuries. Injury rate increased with a higher speed and was higher among males than in females.

Epipsammic diatoms in streams influenced by urban pollution, São Carlos, SP, Brazil

Epipsammic diatoms have important implications for ecosystem processes in lotic environments. Most of the studies on benthic diatoms concentrate on epilithic diatoms and very little is known about epipsammic diatoms. The objective of this study was to assess epipsammic diatom communities in streams in relation to environmental conditions. Epipsammic diatoms and water quality sampling was done at 7 sites during summer base flow period (2008). Forward stepwise multiple regression and canonical correspondence analysis (CCA) were used to determine environmental gradients along which species vary with physical and chemical variables. A total of 112 diatom species distributed among 44 genera were recorded. Altitude and the process of eutrophication played a significant role in structuring diatom communities in the study region.

Biological monitoring of lotic ecosystems: the role of diatoms

Increasing anthropogenic influence on lotic environments as a result of civilisation has captured public interest because of the consequent problems associated with deterioration of water quality. Various biological monitoring methods that provide a direct measure of ecological integrity by using the response of biota to environmental changes have been developed to monitor the ecological status of lotic environments. Diatoms have been used extensively in this regard and this review attempts to summarise the basic concepts associated with biological monitoring using benthic diatoms. Where possible, examples from work carried out in Brazil are used.