Analysis of genetic diversity of two African leafy vegetables, spider plant (Cleome gynandra) and cowpea (Vigna unguiculata), reproductive characteristics and nutritional analysis of spider plant

[no abstract

Interplanting Annual Ryegrass, Wheat, Oat, and Corn to Mitigate Iron Deficiency in Dry Beans

This study evaluated whether grass intercropping can be used to alleviate Fe deficiency chlorosis in dry beans (Phaseolus vulgaris L.) grown in high pH, calcareous soils with low organic matter. Field studies were conducted at the University of Wyoming Sustainable Agriculture Research and Extension Center in 2009 and 2010. Black- and navy beans were grown alone or intercropped with annual ryegrass (Lolium multiflorum Lam.), oat (Avena sativa L.), corn (Zea mays L.), or spring wheat (Triticum aestivum L.) in a two-factor factorial strip-plot randomized complete block design. All four grass species increased chlorophyll intensity in dry beans. However, grass species did not increase iron (Fe) concentration in dry bean tissues suggesting inefficient utilization of Fe present in the dry bean tissues. In 2009, nitrate-nitrogen (NO3-N) and manganese (Mn) concentration in bean tissue were greater in bean monoculture than in grass intercropped beans. Bean monoculture also had greater soil NO3-N concentrations than grass intercropped treatments. In 2009, grass intercrops reduced dry bean yield \u3e25% compared to bean monoculture. Annual ryegrass was the least competitive of the four annual grass species. This suggests that competition from grasses for nutrients, water, or light may have outweighed benefits accruing from grass intercropping. Additional studies are required to determine the appropriate grass and dry bean densities, as well as the optimum time of grass removal

The Perception of Farmers on Climate Change and Variability Patterns in the Nzoia River Basin, Kenya

Global research experts have indicated that there is a growing trend in climate change and variability. Climate change has been altering the exposure of countries to weather related hazards, often exacerbating already existing vulnerabilities over the recent decades. Increasingly, the weather experienced then in terms of amounts of rainfall and temperature is no longer the same as it has always been over centuries based on previous records and scientific findings.   This paper sought to establish the perception of farmers on climate variability and patterns in the Nzoia River Basin, Kenya. The study adopted descriptive, and correlative research design. Data was collected using questionnaires, interview schedules and documented resource materials. The collected data was analyzed using Statistical Package for Social Scientists (SPSS) whereas climatic data of rainfall and temperature from Kenya Meteorological Service (KMS) and hectarage, and yield from the Ministry of Agriculture was analyzed using Microsoft excel. Results were presented in form of tables, charts and graphs. The study indicated that farmers had perceived an increase in temperature a decrease in rainfall, delay in onset of the rains, erratic and poor distribution of rainfall over the study period. The farmer’s perceptions on climate risk as a result of climate change and variability taking place in the basin has greatly influenced the cropping calendar, on-farm investments and decision-making in agricultural management and production negatively affecting yield of maize in the region.  The study recommends that the Government could help  to counteract the impact of climate change on agriculture by investing in research, soil conservation measures, technology, irrigation and water harvesting development, establishing local meteorology stations that will  give farmers relevant meteorological advice that will help them make informed farming options in each farming season. Keywords: Climate change, Climate variability, Perception, Weather

Potential of hemp (Cannabis sativa L.) for paired phytoremediation and bioenergy production

Hemp (Cannabis sativa L.) is a multi-use crop that has been investigated for its potential use in phytoremediation of heavy metals, radionuclides, and organic contaminants, and as a feedstock for bioenergy production. A review of research literature indicates that hemp is a suitable crop for phytoremediation, and a competitive option for bioenergy. Coupling phytoremediation and bioenergy production from a single hemp crop is a potential solution to overcoming the economic constraints of phytoremediation projects. The current challenge is ensuring that the extracted contaminants are not introduced into the consumer marketplace. After several decades of limited research on hemp in the United States, the purpose of this review is to identify the knowledge available for hemp applications in phytoremediation or in production of bioenergy, and if and how those two purposes have been combined. The literature shows that hemp growth has been demonstrated successfully at the field scale for phytoremediation and in several bioenergy conversion technologies. Little is known about the fate of contaminants during hemp growth or during post-harvest processing, especially the relationships between hemp genetics, metabolomics, and contaminant partitioning. Complicating the understanding is the expectation that contaminant fate will be dependent on the contaminant type, the concentration in the material, and the processing methods. Before hemp from phytoremediation applications can be used for bioenergy, the fractionation of heavy metals, radionuclides, and/or organic compounds during transesterification, anaerobic digestion, fermentation, and/or combustion of hemp must be evaluated

Volunteer Corn (Zea mays) Interference in Dry Edible Bean (Phaseolus vulgaris)

Volunteer corn can affect dry bean by reducing yields; expanding the life cycle of insects, mites, and pathogens; interfering with harvest; and contaminating bean seed. Field studies were conducted at Lingle, WY, and Scottsbluff, NE, to determine the relationship between volunteer corn density and dry bean yield, establish the proper time of volunteer corn removal, and determine whether dry bean yield was affected by the method used to remove volunteer corn. Volunteer corn reduced dry bean yields, as recorded in other crops. Growing conditions for each location were different, as indicated by the accumulated growing degree days (GDD): Lingle 2008 (990), Lingle 2009 (780), and Scottsbluff 2009 (957). No difference in dry bean yields was observed between hand removal of volunteer corn and herbicide application. Dry bean yield loss increased with longer periods of volunteer corn competition and ranged from 1.2 to 1.8% yield loss for every 100 GDD that control was delayed. Control measures should be implemented 15 to 20 d after planting when volunteer corn densities are close to 1 plant m−2. Dry bean yield losses also increased as volunteer corn densities increased, with losses from 6.5 to 19.3% for 1 volunteer corn plant m−2. Based on 2015 prices, the cost of controlling volunteer corn would be the equivalent of 102 kg ha−1 of dry bean, and potential losses above 4% would justify control and should not be delayed beyond 15 to 20 d after planting

Dairy value chains in East Africa: Why so few women?

Peer Revie

Impacts of Organic and Conventional Management on the Nutritional Level of Vegetables

The nutrient concentration of fruits and vegetables in the U.S.A. has declined in the past 50–70 years. Crop management practices utilizing on-farm inputs are thought to increase crop nutritional quality, but few studies have evaluated this under long-term side-by-side trials. An experiment was conducted from 2004 to 2005 at Rodale Institute’s long-term Farming Systems Trial to investigate the nutritional quality of vegetables under organic manure (MNR) and conventional (CNV) farming systems, with or without arbuscular mycorrhizal fungi (AMF) treatment. AMF reduced the vitamin C content in carrots in both systems in 2004, but the reduction was 87% in CNV and 28% in MNR. AMF also reduced antioxidants in carrots in both CNV and MNR. This trend was likely due to the suppression of native AMF colonization by the non-native AMF inoculum used. Between 2004 and 2005, MNR increased the vitamin C in green peppers by 50% while CNV decreased the vitamin C in red peppers by 48%. Tomatoes under MNR had a 40% greater vitamin C content compared to CNV in 2005. The vegetable yield declined between 2004 and 2005, except for tomato, where the yield increased by 51% and 44% under CNV and MNR, respectively. In general, MNR tended to increase the nutrient concentration of vegetables compared with CNV, while the AMF effects were inconclusive

Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production

Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha-1 in MT and$149.60 ha-1 in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations

Molecular Markers for Genetic Diversity Studies in African Leafy Vegetables

African leafy vegetables are becoming important crops in tackling nutrition and food security in many parts of sub-Saharan Africa, since they provide important micronutrients and vitamins, and help resource-poor farm families bridge lean periods of food shortage. Genetic diversity studies are essential for crop improvement programmes as well as germplasm conservation efforts, and research on genetic diversity of these vegetables using molecular markers has been increasing over time. Diversity studies have evolved from the use of morphological and biochemical markers to molecular markers. Molecular markers provide valuable data, since they detect mostly selectively neutral variations at the DNA level. They are well established and their strengths and limitations have been described. New marker types are being developed from a combination of the strengths of the basic techniques to improve sensitivity, reproducibility, polymorphic information content, speed and cost. This review discusses the principles of some of the established molecular markers and their application to genetic diversity studies of African leafy vegetables with a main focus on the most common Solanum, Amaranthus, Cleome and Vigna species.BMBF/HORTINLEABM

Distinct Distribution of Archaea From Soil to Freshwater to Estuary: Implications of Archaeal Composition and Function in Different Environments

In addition to inhabiting extreme territories, Archaea are widely distributed in common environments spanning from terrestrial to aquatic environments. This study investigated and compared archaeal community structures from three different habitats (representing distinct environments): agriculture soils (from farming system trials FST, PA, United States), freshwater biofilms (from White Clay Creek, PA, United States), and estuary water (Chesapeake Bay, United States). High-throughput sequencing of 16S rRNA genes indicated that Thaumarchaeota, Euryarchaeota, Nanoarchaeota, Crenarchaeota, and Diapherotrites were the commonly found dominant phyla across these three environments. Similar to Bacteria, distinct community structure and distribution patterns for Archaea were observed in soils vs. freshwater vs. estuary. However, the abundance, richness, evenness, and diversity of archaeal communities were significantly greater in soils than it was in freshwater and estuarine environments. Indicator species (or amplicon sequence variants, ASVs) were identified from different nitrogen and carbon cycling archaeal groups in soils (Nitrososphaerales, Nitrosotaleales, Nitrosopumilales, Methanomassiliicoccales, Lainarchaeales), freshwater biofilms (Methanobacteria, Nitrososphaerales) and Chesapeake Bay (Marine Group II, Nitrosopumilales), suggesting the habitat-specificity of their biogeochemical contributions to different environments. Distinct functional aspects of Archaea were also confirmed by functional predictions (PICRUSt2 analysis). Further, co-occurrence network analysis indicated that only soil Archaea formed stable modules. Keystone species (ASVs) were identified mainly from Methanomassiliicoccales, Nitrososphaerales, Nitrosopumilales. Overall, these results indicate a strong habitat-dependent distribution of Archaea and their functional partitions within the local environments