The impact of conventional and organic farming on soil biodiversity conservation: a case study on termites in the long-term farming systems comparison trials in Kenya

A long-term experiment at two trial sites in Kenya has been on-going since 2007 to assess the effect of organic and conventional farming systems on productivity, profitability and sustainability. During these trials the presence of significant numbers of termites (Isoptera) was observed. Termites are major soil macrofauna and within literature they are either depict as ‘pests’ or as important indicator for environmental sustainability. The extent by which termites may be managed to avoid crop damage, but improve sustainability of farming systems is worthwhile to understand. Therefore, a study on termites was added to the long-term experiments in Kenya. The objectives of the study were to quantify the effect of organic (Org) and conventional (Conv) farming systems at two input levels (low and high) on the abundance, incidence, diversity and foraging activities of termites. The results showed higher termite abundance, incidence, activity and diversity in Org-High compared to Conv-High, Conv-Low and Org-Low. However, the termite presence in each system was also dependent on soil depth, trial site and cropping season. During the experiment, nine different termite genera were identified, that belong to three subfamilies: (i) Macrotermitinae (genera: Allodontotermes, Ancistrotermes, Macrotermes, Microtermes, Odontotermes and Pseudocanthotermes), (ii) Termitinae (Amitermes and Cubitermes) and (iii) Nasutitiermitinae (Trinervitermes). We hypothesize that the presence of termites within the different farming systems might be influenced by the types of input applied, the soil moisture content and the occurrence of natural enemies. Our findings further demonstrate that the organic high input system attracts termites, which are an important, and often beneficial, component of soil fauna. This further increases the potential of such systems in enhancing sustainable agricultural production in Kenya

Insecticide contamination in organic agriculture: Evidence from a long-term farming systems comparison trial

Synthetic pesticides applied in conventional agriculture to control pests tend to compromise ecosystem services, and their residues may contaminate organic agriculture. To understand the significance of this contamination, also in small-scale farming systems in sub-Saharan Africa, quantitative data is required. Therefore, we compared synthetic insecticide and botanical/biopesticide residues in conventional and organic agricultural production systems after nine years of continuous cultivation of a maize-based crop rotation system at two sites in Kenya. Our results show high detectable concentrations of synthetic insecticide residues (imidacloprid, acetamiprid, chlorpyrifos, and chlorantraniliprole) in conventional plant produce and soil. Furthermore, the organophosphate chlorpyrifos was detected at concentrations above European Union Maximum Residue Limits (MRL) for plant produce, indicating potential risks for human health. Additionally, we detected imidacloprid, acetamiprid, chlorpyrifos, and chlorantraniliprole concentrations in the soil, indicating potential environmental harm. No residues of biopesticide/botanicals were detected in any of the production systems. However, we detected imidacloprid and chlorantraniliprole in organic plots. The findings indicate that the MRLs can be crossed even if synthetic insecticides are applied according to or below the recommended rates on the conventional plots. Thus, synthetic insecticides potentially risk human health and the environment, while botanicals and bio-pesticides represent a safe alternative

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Effect of organic and conventional farming systems on nitrogen use efficiency of potato, maize and vegetables in the Central highlands of Kenya

Increased per capita food production in the tropics is closely tied to soil organic matter and water management, timely nitrogen (N) supply and crop N use efficiency (NUE) which are influenced by farmingsystems. However, there is lack of data on the effect of organic farming systems on NUE and how thiscompares to conventional farming systems under tropical conditions. Therefore, the objectives of thisstudy were to determine the effect of conventional and organic farming systems at low and high management intensities on N uptake and N use efficiency of potato (Solanum tuberosum L.), maize (Zea mays L.),cabbage (Brassica oleracea var. Capitata), kale (Brassica oleracea var. Acephala) and Swiss chard (Beta vul-garis sub sp. Cicla). The organic high input (Org-High) and conventional high input (Conv-High) farmingsystems are managed as recommended by research institutions while organic low input (Org-Low) andconventional low input (Conv-Low) farming systems are managed as practiced by small scale farmers inthe Central highlands of Kenya. The study was conducted during three cropping seasons between October2012 and March 2014 in an ongoing long-term trial established since 2007 at Chuka and at Thika, Kenya.Synthetic N-based fertilizer and cattle manure were applied at ∼225 kg N ha−1yr−1for Conv-High and at∼50 kg N ha−1yr−1for the Conv-Low. Composts and other organic inputs were applied at similar N ratesfor Org-High and Org-Low. Nitrogen uptake efficiency (NUpE) of potato was highest in Conv-Low andOrg-Low at Thika and lowest in Org-High and Org-Low at Chuka site where late blight disease affectedpotato performance. In contrast, the NUpE of maize was similar in all systems at Chuka site, but was sig-nificantly higher in Conv-High and Org-High compared to the low input systems at Thika site. The NUpEof cabbage was similar in Conv-High and Org-High while the NUpE of kale and Swiss chard were similarin the low input systems. Potato N utilization efficiencies (NUtE) and agronomic efficiencies of N use(AEN) in Conv-Low and Conv-High were 11–21 % and 1.4–3.4 times higher than those from Org-Low andOrg-High, respectively. The AENof maize was similar in all the systems at Chuka but was 3.2 times higherin the high input systems compared to the low input systems at the Thika site. The AENof vegetablesunder conventional systems were similar to those from organic systems. Nitrogen harvest index (NHI) ofpotato was similar between Conv-High and Org-High and between Conv-Low and Org-Low. N partitionedinto maize grain was similar in all the system at Chuka, but significantly lower (P < 0.001) in Conv-lowand Org-Low at Thika site. The NHI of cabbage in Org-High was 24 % higher than that of Conv-High. Thestudy concluded that for maize and vegetables, conventional and organic farming systems had similareffects on NUpE, AEN, NUtE and NHI, while for potato conventional systems improved NUE comparedto organic systems. The study recommends that management practices for potato production in organicsystems should be improved for a more efficient NUE

What is the contribution of organic agriculture to sustainable development? Results from the Long-term Farming Systems Comparisons Trials

The farming systems comparisons trials in Kenya have been running since 2007 at two trial sites (Chuka and Thika). The trials compare the economic, ecological, and sustainable performance of organic and conventional farming systems at a high and low input level. Results showed comparable productivity in conventional and organic systems for cereals but lower yields in organic for potatoes and leafy vegetables. Production costs are generally higher in organic due to the higher labor costs. However, soil fertility and biodiversity are better in organic systems. To fully exploit the potential of organic systems, further innovations in organic pest and input management have to be developed, and capacity building has to be strengthened

Soil quality and phosphorus status after nine years of organic and conventional farming at two input levels in the Central Highlands of Kenya

Under temperate climate conditions, organic farming systems show improved soil quality compared to non-organic systems, whereas little long-term research on the impact of organic farming on soil quality has been conducted in sub-Saharan Africa. Within the system comparison (SysCom) project, two long-term field experiments were set up in 2007 in the sub-humid Central Highlands of Kenya to compare organic and conventional farming at two input levels (high input systems with recommended rates of nitrogen (N), phosphorus (P) and pesticides and with irrigation vs. rain-fed low input systems with low N, P and pesticides), with a similar design at both sites. The two sites differ mainly in their inherent soil properties and in the amount and distribution of rainfall. At the end of each three-year crop rotation period, we analyzed a set of chemical, biological and physical soil quality parameters in 0–20 cm soil depth. After nine years, microbial parameters seemed to have reached a steady state, whereas chemical parameters were still changing. Most soil quality parameters were highest under the high input organic farming system. The high input conventional system performed well in preserving several soil quality indicators, but a trend for acidification and the lack of soil carbon build-up raise concerns about the long-term sustainability of the system. Low input organic and conventional farming systems did not improve soil quality and even showed decreasing trends in several chemical parameters. Total and available P accumulated over time, especially in both high input systems, suggesting increasing risks of losses to the environment. Pronounced site effects revealed strong interactions with pedo-climatic conditions, with soil quality under high input organic farming improving to a greater extent at the site with more favorable conditions. Besides effects on soil quality, important criteria for sustainable input levels are thus the general availability of inputs, resulting nutrient input–output budgets as well as interactions of inputs with inherent soil properties

Nitrogen release and synchrony in organic and conventional farming systems of the Central Highlands of Kenya

To match Nitrogen (N) supply to crop N demand, it is essential to understand N release and uptake patterns in different farming systems and crops. To assesses the dynamics of N released in organic and conventional systems and potential synchrony and asynchrony in crop N uptake, a study was conducted over three cropping seasons (potato, maize and leafy vegetables) at two sites in the Central Highlands of Kenya. Mineral-N release and synchrony were monitored in conventional and organic systems at high (recommended N, P, pesticides and irrigation) and low input (low N, P, pesticide use and rainfed) systems. Mineral-N release was assessed using in situ buried bags and N synchrony was measured by the daily differences in N fluxes. The percentage of N applied released during potato (38%) and vegetable (44%) cropping seasons were similar between systems. However, under maize strong temporal N immobilization from inputs occurred, particularly at Thika, related to the poor quality of manure and compost (lignin:N ratio > 13). In all systems, excess-asynchrony of available N was pronounced during vegetative stages and at harvest, while insufficient-asynchrony occurred at reproductive stages. During potato cropping season at Thika, Org-High showed highest positive N fluxes (> 20 kg N ha−1 day−1) at planting and tuber bulking stage. At early stages of maize and vegetables Org-Low and Org-High experienced up to 5 times larger negative N fluxes (insufficiency) compared to conventional treatments at Chuka site. The study recommends reducing N applications at planting and increasing N dosages at reproductive stages of crops