Limiting nutrients for bean production on contrasting soil types of Lake Victoria Crescent of Uganda

Common bean (Phaseolus vulgaris L.) is one of the most important grain legumes in East Africa, but its yield has remained below the genetic potential. Declining soil fertility is among the primary constraints to bean production in most East African bean producing regions. Often existing recommendations are generic and inept to guide farm level decision making on nutrient replenishment. A greenhouse nutrient omission study was conducted to determine the limiting nutrients in three soils of Masaka District, commonly cropped to beans: \u201cLiddugavu\u201d a Phaeozem, \u201cLimyufumyufu\u201d a Cambisol and \u201cLuyinjayinga\u201d an Umbrisol soil. Nine treatments; (i) complete nutrient treatment, (ii) N omitted, (iii) P omitted, (iv) K omitted, (v) Mg omitted, (vi) S omitted, (vii) Ca omitted, (viii) Micronutrients omitted and (ix) control without nutrients. Each treatment was randomly assigned to the three soils and replicated three times using a completely randomised design. Nitrogen, phosphorus and potassium were limiting nutrients for bean production in Umbrisol (Luyinjayinja) while in Cambisol (\u2018Limyufumyufu), common bean production was most limited by soil acidity. The performance varied with soil types, with beans grown on the Phaeozem registering greater leaf number and growth, confirming both scientist\u2019s and local farmer\u2019s knowledge that this soil has greater potential than the other two soils.Le haricot commun (Phaseolus vulgaris L.) est un des l\ue9gumes \ue0 grains les plus importants en Afrique de l\u2019Est, mais son rendement reste toujours en dessous de son potentiel g\ue9n\ue9tique. La baisse de la fertilit\ue9 du sol est parmi les contraintes primaires \ue0 la production du haricot dans la plupart des r\ue9gions productrices de l\u2019Afrique de l\u2019Est. Le plus souvent, les recommandations sont g\ue9n\ue9riques et inad\ue9quates pour guider la prise de d\ue9cision au niveau champ sur le r\ue9approvisionnement en nutriment. Une \ue9tude sous serre sur l\u2019omission de nutriment a \ue9t\ue9 conduite pour d\ue9terminer les nutriments limitants dans les trois sols du district de Masaka, commun\ue9ment utilis\ue9s pour produire du haricot\ua0: \u201cLiddugavu\u201d un sol du Phaeozem, \u201cLimyufumyufu\u201d un sol du Cambisol et \u201cLuyinjayinga\u201d un sol du Umbrisol. Neuf traitements, (i) traitement complet de nutriments, (ii) N omis, (iii) P omis, (iv) K omis, (v) Mg omis, (iv) S omis, (vii) Ca omis, (viii) micronutriments omis et (ix) control sans nutriments. Chacun des traitements a \ue9t\ue9 al\ue9atoirement distribu\ue9 aux trois types de sols et r\ue9pliqu\ue9 trois fois dans un dispositif compl\ue8tement al\ue9atoire. Azote, phosphore, et potassium ont \ue9t\ue9 les nutriments limitants pour la production du haricot dans Umbrisol (Luyinjayinja) tandis que dans Cambisol (\u2018Limyufumyufu), la production du haricoct commun a \ue9t\ue9 limit\ue9e par l\u2019acidit\ue9 du sol. Les performances varient en fonction des types de sols, avec le haricot produit sur le Phaeozem comptant plus de feuilles et de croissance, confirmant \ue0 la fois les connaissances des scientifiques et des populations locales qui stipulent que le sol a un potentiel plus \ue9lev\ue9 que les deux autres sols

Soils and agriculture in central-west and north Brazil

Modern soil science, spearheaded by research in Brazil has facilitated the utilization of vast areas of previously uncultivated soil long considered unsuitable for human food production into highly productive agricultural land. Naturally acid soils with high contents of aluminum and iron oxides and low CEC values and organic matter contents long considered insurmountable obstacles to crop production in tropical latitudes could be extremely productive. With continued development of the infrastructure needed by commercial agriculture Brazil has the potential to lead the world in its quest to provide food for growing human populations.A moderna ciência de solo, liderada pelas suas pesquisas no Brasil, tem possibilitado a utilização de vastas áreas de solos, durante muito tempo não cultivados por serem avaliados como inaptos para uma intensiva produção de alimentos. Hoje, ao contrário, constata-se que essas terras são altamente produtivas para a agricultura. Estas pesquisas vêm mostrando que alguns atributos naturais destes solos, como acidez, baixos teores de matéria orgânica, baixa capacidade de troca de cátions, além de altos teores de óxidos de ferro e/ou de alumínio - considerados como obstáculos à produção de boas colheitas em latitudes tropicais - podem ser superados. Com a continuação do desenvolvimento das infra-estruturas necessárias para alavancar ainda mais a agricultura comercial, o Brasil tem potencial para, em breve, liderar o mundo no que tange ao fornecimento de alimentos para as crescentes populações humanas

Setting a baseline for global urban virome surveillance in sewage

The rapid development of megacities, and their growing connectedness across the world is becoming a distinct driver for emerging disease outbreaks. Early detection of unusual disease emergence and spread should therefore include such cities as part of risk-based surveillance. A catch-all metagenomic sequencing approach of urban sewage could potentially provide an unbiased insight into the dynamics of viral pathogens circulating in a community irrespective of access to care, a potential which already has been proven for the surveillance of poliovirus. Here, we present a detailed characterization of sewage viromes from a snapshot of 81 high density urban areas across the globe, including in-depth assessment of potential biases, as a proof of concept for catch-all viral pathogen surveillance. We show the ability to detect a wide range of viruses and geographical and seasonal differences for specific viral groups. Our findings offer a cross-sectional baseline for further research in viral surveillance from urban sewage samples and place previous studies in a global perspective

Liming in the Tropics: Variable-Charge Soils May Be Highly Buffered

Yield response of cowpea over a pH gradient established by applying incremental amounts of lime to an Oxisol is illustrated and discussed

Green Manuring—Renewed Interest in an Old Concept

Three tropical green manure legumes were grown across a pH gradient from 4.7 to 7.1 established by liming an Oxisol. The effects of available soil aluminum and manganese levels on plant growth and nitrogen fixation are discussed

Adequate Nutrient Levels in Soils and Plants in Hawaii

Soil analysis levels considered adequate for three broad soil bulk density categories are given, along with "sufficiency" nutrient levels in the tissues of 12 common crops (vegetable, fruit, forage, and turf)