Production systems and contributions of grain legumes to soil health and sustainable agriculture: A review

Sustainable development of agriculture is essential, and there is unanimity that diversification of the cropping systems could support sustainable production. Grain legumes are essential in farming systems in terms of food and nutrition security and income generation. Under legume-based cropping systems, these crops are a potential remedy to pest and disease issues, low nutrient supply, biodiversity protection, and food and nutrition insecurity. In this chapter, we highlight the production systems of legumes and their use in sustainable agricultural production. Specifically, we have looked at the benefits of having a legume cropping system in the agroecosystem, production, and farming systems. The function of legumes in improving the potential of crop productivity is a promising approach to tackling the challenges of poor crop yields and improvement in sustainable production. Due to health and environmental benefits, the focus should shift to breeding grain legumes that can fully express their biological nitrogen fixation and other potentials under abiotic and biotic limitations

Prevalence and risk factors associated with the occurrence of Campylobacter sp. in children aged 6–24 months in peri-urban Nairobi, Kenya

IntroductionCampylobacter bacteria is a major cause of foodborne-related bacterial gastroenteritis in humans worldwide. It is known to cause diarrhea in young children which has been shown to directly affect their weight and height as a result of malnutrition. Severe cases of diarrhea can also lead to death. Most of the burden is experienced in resource-limited countries in Africa and Southeast Asia where the disease is linked to poor hygiene and sanitation. The objective of this study was to determine the prevalence of Campylobacter in children aged between 6 and 24 months in Nairobi, Kenya and identify potential risk factors associated with their occurrence.MethodsA cross-sectional study was carried out between May to December 2021. A total of 585 randomly selected households were visited in two wards (Uthiru/Ruthimitu and Riruta) in Dagoretti South sub-county, Nairobi. A questionnaire regarding how children’s food is handled, the major foods consumed, sanitation and hygiene, and animal ownership was conducted among caregivers to identify associated risk factors. Stool samples were collected from 540/585 children and screened for the presence of Campylobacter using culture-based methods and confirmed through PCR.ResultsOf the 540 children’s stool samples processed, Campylobacter isolates were detected in 4.8% (26/540). Campylobacter jejuni (C. jejuni) was the most common species in 80.8% of positive samples compared to Campylobacter coli (C. coli) in 26.9% of samples. In six samples, both C. jejuni and C. coli were isolated, while in four samples, it was not possible to speciate the Campylobacter. Drinking cow’s milk (OR 4.2, 95% CI 1.4 – 12.6) and the presence of animal feces in the compound (OR 3.4, 95% CI 1.1 – 10.3) were found to be statistically associated with Campylobacter carriage in children.DiscussionThe carriage of Campylobacter in children in this community indicates a need for further investigation on source attribution to understand transmission dynamics and inform where to target interventions. Awareness creation among caregivers on good personal and food hygiene is needed, including boiling milk before consumption. Implementation of biosecurity measures at the household level is highly recommended to reduce contact between animals and humans

Constraints, interventions and prospects for improving pearl millet (Pennisetum glaucum L.) production in the state of Eritrea - A review

Pearl millet (Pennisetum glaucum L.) is the second most important cereal grown in Eritrea after sorghum (Sorghum bicolor L.) grown under low input systems by small scale farmers. The crop utilizes soil moisture efficiently and has ability to tolerate soil toxicity and extreme temperatures than other cereals. It is a sustenance and food security crop important for its nutritive and cultural value and provides dietary energy and nutrition. However, despite the positive attributes and qualities of pearl millets for the present and future agriculture, production has been low. We attribute this to inadequate rainfall distribution, poor crop management by poorly resourced farmers, unavailability and high prices of farm inputs such as fertilizer and pesticides and low adoption of improved varieties by the farmers. This review outlines the constraints, interventions the government/ farmers have and can implement and the prospects of actions that can improve pearl millet production. As much as there have been efforts by the government and stakeholders to address these challenges and improve productivity of pearl millet, more needs to be done to meet the increasing demand of the increasing populations. This will enable farmers to intensify and diversify their agricultural systems and improve food security situation in the country. Unless a combined effort in soil fertility improvement, policies to promote use of modern varieties and conservation of and promotion of this crop biodiversity, the potential of this crop as famine and poverty alleviation among the rural poor will not be realized

Residual Effects of Lablab Green Manure on Root Rot Pathogens and Performance of Common Bean (Phaseolus Vulgaris L)

Organic manures often have considerable residual effect on the subsequent crops in the soil. Residual effects of lablab green manure on root rot pathogens and bean crop establishment was evaluated by conducting field experiments at two sites with varying soil fertility in Nandi South. Common bean varieties KK8 and GLP2 seeds were planted on plots previously treated with different soil amendments. Soil samples were collected before planting and six weeks after emergence to determine the populations of root rot pathogens. Throughout the experiment, data was collected on crop emergence, plant stand, root rot incidence and severity, as well as crop yield. There was increase in crop emergence by 40% for GLP2 and 19% for KK8 with corresponding 7% reduction in root rot incidence in plots previously treated with lablab green manure. There was varitions in the population of root rot pathogens between the two studies, with Kapkerer exhibiting a higher pathogen population compared to Koibem. The primary root rot pathogens isolated and identified were F. solani, F. oxysporum and Pythium ultimum. F. solani and F. oxysporum were the most dominant species isolated in over 90% plant and soil samples. Residual plots treated with lablab green manure recorded a substantial in yield with an impressive increase of 22% when compared to other treatments. Correlation analysis established that disease incidence, and severity was negatively correlated with yield while plant stand was positively correlated with yield. Our research highlights the long-term benefits of lablab green manure as an organic soil amendment, showcasing its ability to improve crop emergence, reduce root rot incidence, and boost overall crop yield. This knowledge can guide farmers in optimizing their agricultural practices for increased productivity and sustainable soil health

Constraints, interventions and prospects for improving pearl millet (Pennisetum glaucum L.) production in the state of Eritrea - A review

Pearl millet (Pennisetum glaucum L.) is the second most important cereal grown in Eritrea after sorghum (Sorghum bicolor L.) grown under low input systems by small scale farmers. The crop utilizes soil moisture efficiently and has ability to tolerate soil toxicity and extreme temperatures than other cereals. It is a sustenance and food security crop important for its nutritive and cultural value and provides dietary energy and nutrition. However, despite the positive attributes and qualities of pearl millets for the present and future agriculture, production has been low. We attribute this to inadequate rainfall distribution, poor crop management by poorly resourced farmers, unavailability and high prices of farm inputs such as fertilizer and pesticides and low adoption of improved varieties by the farmers. This review outlines the constraints, interventions the government/ farmers have and can implement and the prospects of actions that can improve pearl millet production. As much as there have been efforts by the government and stakeholders to address these challenges and improve productivity of pearl millet, more needs to be done to meet the increasing demand of the increasing populations. This will enable farmers to intensify and diversify their agricultural systems and improve food security situation in the country. Unless a combined effort in soil fertility improvement, policies to promote use of modern varieties and conservation of and promotion of this crop biodiversity, the potential of this crop as famine and poverty alleviation among the rural poor will not be realized

Residual Effects of Lablab Green Manure on Root Rot Pathogens and Performance of Common Bean (Phaseolus Vulgaris L)

Organic manures often have considerable residual effect on the subsequent crops in the soil. Residual effects of lablab green manure on root rot pathogens and bean crop establishment was evaluated by conducting field experiments at two sites with varying soil fertility in Nandi South. Common bean varieties KK8 and GLP2 seeds were planted on plots previously treated with different soil amendments. Soil samples were collected before planting and six weeks after emergence to determine the populations of root rot pathogens. Throughout the experiment, data was collected on crop emergence, plant stand, root rot incidence and severity, as well as crop yield. There was increase in crop emergence by 40% for GLP2 and 19% for KK8 with corresponding 7% reduction in root rot incidence in plots previously treated with lablab green manure. There was varitions in the population of root rot pathogens between the two studies, with Kapkerer exhibiting a higher pathogen population compared to Koibem. The primary root rot pathogens isolated and identified were F. solani, F. oxysporum and Pythium ultimum. F. solani and F. oxysporum were the most dominant species isolated in over 90% plant and soil samples. Residual plots treated with lablab green manure recorded a substantial in yield with an impressive increase of 22% when compared to other treatments. Correlation analysis established that disease incidence, and severity was negatively correlated with yield while plant stand was positively correlated with yield. Our research highlights the long-term benefits of lablab green manure as an organic soil amendment, showcasing its ability to improve crop emergence, reduce root rot incidence, and boost overall crop yield. This knowledge can guide farmers in optimizing their agricultural practices for increased productivity and sustainable soil health

Effect of Legume Extracts on Germination, Seedling Health of Beans (Phaseolus vulgaris L.) and Soil Microorganisms

Application of undecomposed green manure has been reported to cause poor emergence and establishment of common beans in the field. Therefore, to understand the mechanisms’ contributing to the poor crop establishment, the effect of extracts from fresh and decomposed legume green manures on bean seed germination, fungal mycelial growth, spore germination and germ tube elongation were evaluated. The extracts were prepared in either ethanol or distilled water. Data was collected on percentage seed germination, seedling length, mycelial radial growth, spore germination and germ tube elongation. Ethanol extracts from fresh lablab inhibited bean germination by 56%, increased mean germination time to 8 days, and decreased germination index while ethanol extracts of groundnut and beans caused highest inhibition in bean shoot length and reduced biomass. Ethanol extracts from fresh green manures significantly inhibited fungal mycelial growth while the aqueous extracts from beans, groundnuts and soybean had significant level of antifungal activity while aqueous lablab extracts stimulated mycelial. Aqueous extract of lablab and soybean enhanced spore germination by over 70% with more pronounced effect on germ tube length and number of germ tubes by 8.0% and 13% respectively. The study comparatively reveals that the extract of lablab was inhibitory to common bean germination compared to other legume extracts and also stimulated the growth of root rot pathogens that may have resulted in poor establishment of beans

A Method for Selection of Coffee Varieties Resistant to <i>Fusarium stilboides</i>

Fusarium bark disease (FBD) of coffee caused by Fusarium stilboides Steyaert has been associated with yield losses and tree death in coffee-growing countries, including Kenya. Varietal resistance is of utmost importance in managing the disease, and the continued increase in host resistance is considered sufficient to control the disease. Therefore, this study investigated the response of four coffee cultivars to F. stilboides. Fifteen hypocotyls from Coffea arabica (Ruiru 11, Batian and SL 28), plus two other coffee species, Coffea canephora (Robusta coffee) and Coffea liberica (Liberica coffee), were inoculated with various concentrations of three F. stilboides isolates (NRF 930/18, TN002B (I), BS008B (A)) using both the injection and drenching methods. The stem injection method was performed by injecting one microliter of the F. stilboides spore solution into the hypocotyl. In the drenching method, coffee seedlings had their roots cut and transplanted in a transplanting mixture, after which 10 mL of the F. stilboides spore solution was applied to the soil surface in each pot. The inoculated hypocotyls were incubated at 24 ± 2 °C for 105 days. The plants were watered regularly as necessary while the development of symptoms was observed and assessed weekly. Disease severity was evaluated using a modified scale of 0–4, while incidence was scored as a percentage of infected seedlings. Coffee seedlings inoculated with F. stilboides developed symptoms such as wilting, stunted growth and defoliation. In the first season, the coffee cultivars of Ruiru 11 and Liberica inoculated with Fusarium stilboides had pronounced severity compared to other cultivars. In the second season, the coffee cultivars Batian and Ruiru 11 had pronounced severity compared to other cultivars. The isolate TN002B (I) was observed to be highly virulent as compared to other isolates. The variation in response to disease infection exhibited by the four cultivars presents a key input in breeding programs for resistance to F. stilboides

Risk factors for diarrheagenic Escherichia coli infection in children aged 6-24 months in peri-urban community, Nairobi, Kenya

Escherichia coli commonly inhabits the gut of humans and animals as part of their microbiota. Though mostly innocuous, some strains have virulence markers that make them pathogenic. This paper presents results of a cross-sectional epidemiological study examining prevalence of diarrheagenic E. coli (DEC) pathotypes in stool samples of asymptomatic healthy children (n = 540) in Dagoretti South subcounty, Nairobi, Kenya. E. coli was cultured and pathotyped using PCR to target specific virulence markers associated with Shiga-toxin, enteropathogenic, enterotoxigenic, enteroaggregative, entero-invasive and diffusely adherent E. coli. Overall prevalence of DEC pathotypes was 20.9% (113/540) with enteropathogenic E. coli being the most prevalent (34.1%), followed by enteroaggregative E. coli (23.5%) and Shiga-toxin producing E. coli (22.0%) among positive samples. We found evidence of co-infection with multiple pathotypes in 15% of the positive samples. Our models indicated that at the household level, carriage of DEC pathotypes in children was associated with age group [12-18 months] (OR 1.78; 95%CI 1.03-3.07; p = 0.04), eating matoke (mashed bananas) (OR 2.32; 95%CI 1.44-3.73; p = 0.001) and pulses/legumes (OR 1.74; 95%CI 1.01-2.99; p = 0.046) while livestock ownership or contact showed no significant association with DEC carriage (p>0.05). Our findings revealed significant prevalence of pathogenic DEC circulating among presumptive healthy children in the community. Since there has been no previous evidence of an association between any food type and DEC carriage, unhygienic handling, and preparation of matoke and pulses/legumes could be the reason for significant association with DEC carriage. Children 12-18 months old are more prone to DEC infections due to exploration and hand-to-mouth behavior. A detailed understanding is required on what proportion of positive cases developed severe symptomatology as well as fatal outcomes. The co-infection of pathotypes in the rapidly urbanizing environment needs to be investigated for hybrid or hetero-pathotype circulation that have been implicated in previous infection outbreaks

Table_2_Prevalence and risk factors associated with the occurrence of Campylobacter sp. in children aged 6–24 months in peri-urban Nairobi, Kenya.docx

IntroductionCampylobacter bacteria is a major cause of foodborne-related bacterial gastroenteritis in humans worldwide. It is known to cause diarrhea in young children which has been shown to directly affect their weight and height as a result of malnutrition. Severe cases of diarrhea can also lead to death. Most of the burden is experienced in resource-limited countries in Africa and Southeast Asia where the disease is linked to poor hygiene and sanitation. The objective of this study was to determine the prevalence of Campylobacter in children aged between 6 and 24 months in Nairobi, Kenya and identify potential risk factors associated with their occurrence.MethodsA cross-sectional study was carried out between May to December 2021. A total of 585 randomly selected households were visited in two wards (Uthiru/Ruthimitu and Riruta) in Dagoretti South sub-county, Nairobi. A questionnaire regarding how children’s food is handled, the major foods consumed, sanitation and hygiene, and animal ownership was conducted among caregivers to identify associated risk factors. Stool samples were collected from 540/585 children and screened for the presence of Campylobacter using culture-based methods and confirmed through PCR.ResultsOf the 540 children’s stool samples processed, Campylobacter isolates were detected in 4.8% (26/540). Campylobacter jejuni (C. jejuni) was the most common species in 80.8% of positive samples compared to Campylobacter coli (C. coli) in 26.9% of samples. In six samples, both C. jejuni and C. coli were isolated, while in four samples, it was not possible to speciate the Campylobacter. Drinking cow’s milk (OR 4.2, 95% CI 1.4 – 12.6) and the presence of animal feces in the compound (OR 3.4, 95% CI 1.1 – 10.3) were found to be statistically associated with Campylobacter carriage in children.DiscussionThe carriage of Campylobacter in children in this community indicates a need for further investigation on source attribution to understand transmission dynamics and inform where to target interventions. Awareness creation among caregivers on good personal and food hygiene is needed, including boiling milk before consumption. Implementation of biosecurity measures at the household level is highly recommended to reduce contact between animals and humans.</p